The banks in the middle and lower reaches of the Tarim River in China are weak in erosion resistance and prone to collapse.Vegetation,as a natural reinforcement material,can effectively improve slope stability and cur...The banks in the middle and lower reaches of the Tarim River in China are weak in erosion resistance and prone to collapse.Vegetation,as a natural reinforcement material,can effectively improve slope stability and curb soil erosion.In March and July 2023,a field survey was conducted on the types and distribution characteristics of vegetation along both banks of a certain section in the lower reaches of the Tarim River.Taking COMSOL Multiphysics as the finite element numerical simulation platform,we investigated the variation law of bank slope stability in the middle and lower reaches of the Tarim River under different root morphologies,considering changes in transpiration time,rainfall,and water level under the action of hydro-mechanical reinforcement.The findings showed that vegetation transpiration has a significant effect on soil pore water pressure.Given the same transpiration rate,shorter root systems produced greater pore water pressure.For equal root lengths,the pore water pressures generated by roots in exponential and triangular morphologies were significantly greater than those generated by roots in uniformly distributed and parabolic morphologies.The water absorption capacity of the root system increased with transpiration rate.After 7 d of transpiration,the maximum safety factor of the bank slope reinforced by exponential roots was 1.568,which was a 9.88%improvement over that of the bare slope.After 24 h of rainfall,the effect of vegetation transpiration on soil pore water pressure weakened rapidly;the pore water pressure of the surface soil generated by transpiration from vegetation with different root morphologies was concentrated near–10.00 kPa.After rainfall,the displacement of the exponential root reinforced slope was minimized to 0.137 m.The effect of transpiration-induced changes in substrate suction on slope stability was negligible during the rainfall period.Compared with that of the bare slope,the displacements of bank slopes reinforced by root systems significantly increased.The maximum displacement occurred when the water level changed by 1.5 m/d;the displacement of the bare slope was 0.554 m,whereas the displacements of bank slopes reinforced by roots in different morphologies were 0.260–0.273 m.The impact of vegetation transpiration on the safety factor of riverbanks under sudden water level drops was relatively minor,but it can enhance the stability of riverbanks to a certain extent.Among these,riverbanks reinforced by roots in triangular and exponential morphologies exhibited superior stability compared with those reinforced by uniformly distributed or parabolic root systems.The findings offer a theoretical basis and practical guidance for designing vegetation slope protection in the middle and lower reaches of the Tarim River.展开更多
As demand for land resources is rapidly growing nowadays,developing on slope lands has become a way to relieve pressure on flat lands.Although some studies use the concept of slope spectrum to explore the trend of lan...As demand for land resources is rapidly growing nowadays,developing on slope lands has become a way to relieve pressure on flat lands.Although some studies use the concept of slope spectrum to explore the trend of land use upslope,relying solely on the slope spectrum is too broad and prevents deeper research.Therefore,using China's land use and DEM data from 2000 to 2020,our study integrated the slope spectrum and the slope sensitivity coefficient(SSC)calculated by the land use transfer matrix as a new approach and method for understanding the underlying formations and impacts of upslope in farmland and construction land,supporting regional management strategies.The results show that:1)Farmlands were upslope in the South and developed horizontally in the North,and construction lands were upslope nationwide.2)Using the land use transfer matrix and SSC,we classified farmland upslope as passive and active patterns,and construction land upslope as saturation and avoidance patterns based on their land use transfer mechanisms in slope space.Provinces with passive and saturation patterns are mainly located near the east coast.3)Different patterns of upslope have distinct impacts on sustainable development.The passive pattern harms food security while the active pattern can relieve pressure on food security but increases ecological risks.Saturation pattern damages food security,ecological protection,and city livability,but avoidance pattern can promote food security and ecological protection.The findings will serve as an essential reference for developing land use strategies aimed at sustainable development.展开更多
China's requisition-compensation balance strategy has dramatically reshaped cropland spatial patterns,drawing multidisciplinary research attention.However,existing studies predominantly emphasize horizontal distri...China's requisition-compensation balance strategy has dramatically reshaped cropland spatial patterns,drawing multidisciplinary research attention.However,existing studies predominantly emphasize horizontal distribution,overlooking the significant influence of slope gradient on cropland spatial patterns.This paper proposes a slope location quotient(SLQ)index that reflects the relative advantage of cropland distribution and explores the slope grade difference of cropland spatial patterns in China at the county scale.The analysis adopts 30-m resolution digital elevation model with land cover data,taking 2672 counties with cropland ratio>1%as study units.The temporal scope covers 1990 and 2020,with slope gradients categorized into five grades:0°~2°,2°~6°,6°~15°,15°~25°,and 25°~90°.Results show that:1)The inverse correlation between cropland area and slope gradient remained stable throughout the study period,with the variation in cropland area frequency across slope grades being less than 1%.2)The spatial patterns of SLQ in 1990 and 2020 both transited stepwise with slope gradient,while≤2°and>6°slopes exhibited opposing patterns.3)The mean absolute variation of SLQ during 1990-2020 increased with slope gradient(R2=0.926,p<0.01).Particularly for slope grades>15°,the mean absolute variation reached 0.26(for 15°~25°)and 0.43(for 25°~90°),respectively,and displayed a distinct southward-increasing and northwarddecreasing pattern.This study offers novel slopegradient perspectives for analyzing cropland spatial patterns.To enhance cropland protection benefits,reversing the steep cropland SLQ surge in southern China is recommended.展开更多
Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybr...Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybrid control method was proposed.This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative(PID)controller.The speed of agricultural machinery was influenced by longitudinal forces,which were divided into two parts:one part was slope-related forces and conventional resistance,and the other was hard-to-estimate forces,such as sliding friction.For the first part,a slope-based controller was designed;for the second part,a PID controller was implemented.By combining these two controllers,the system can dynamically adjust the throttle opening and the brake master cylinder pressure,ensuring steady speed travel on sloping farmland.Simulation tests at a target speed of 7 km/h demonstrated that the proposed controller maintained a stable speed,achieving a root mean square error of 0.13 km/h and a mean absolute percentage error of 1.6%.Field tests on a practical experimental platform validated the method’s effectiveness,with results showing consistent control performance across varying slope conditions.The proposed controller demonstrated superior control performance.Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed,meeting the stability requirements for agricultural operations.展开更多
Rock slope instability is a prevalent geological hazard that imposes significant adverse impacts on engineering activities.Although existing studies have focused on homogeneous rock slopes,the theoretical models for q...Rock slope instability is a prevalent geological hazard that imposes significant adverse impacts on engineering activities.Although existing studies have focused on homogeneous rock slopes,the theoretical models for quantifying the stability of softhard interbedded anti-inclined slopes remain underdeveloped,primarily due to the complex force transfer mechanisms involved.This study proposed a novel theoretical model for the stability analysis of soft-hard interbedded anti-inclined slopes under rainfall conditions.The framework models stratified rock layers as layered cantilever beams with material heterogeneity.Based on the principle of deformation compatibility,it comprehensively accounted for interlayer force transfer and strength degradation resulting from differential deformations among rock layers.Furthermore,it integrated the critical instability length induced by the self-weight of rock layers to determine the fracture depth.The proposed method was validated against engineering case studies and physical model tests,with error falling within an acceptable range.Compared to existing theoretical methods,the proposed method provided a more realistic representation of the slope's stress field.The analysis results demonstrate that rainfall not only reduces the inclination angle of the failure surface but also leads to an approximate 30%decrease in the safety factor.The proposed theoretical model is particularly useful for quickly calculating the stability of soft-hard interbedded anti-inclined rock slope under rainfall conditions,compared to complex and time-consuming numerical simulation calculations.展开更多
Slopes are likely to fail in areas with frequent rainfall and earthquakes.The deformation characteristics of unsaturated slopes subjected to post-rainfall earthquakes are investigated using centrifuge model tests and ...Slopes are likely to fail in areas with frequent rainfall and earthquakes.The deformation characteristics of unsaturated slopes subjected to post-rainfall earthquakes are investigated using centrifuge model tests and finite element analyses.Three tests of the slope deformation under earthquake and post-rainfall earthquakes are first studied using image analysis techniques.Then,based on an elastoplastic constitutive model,numerical simulations are carried out using the finite element method and compared with the centrifuge test results.Finally,a parametric study is performed to clarify the effects of antecedent rainfall on earthquake-induced slope deformation.The results show that slope deformation caused by post-rainfall earthquakes differs from that caused by earthquakes without antecedent rainfall.The seepage flow and soil strength of the slope are affected by previous rainfall conditions,such as intensity and duration,which directly influence the slope deformation caused by the subsequent earthquake.Soil displacement and strain become greater and the slip surface is more noticeable during the post-rainfall earthquake of higher intensity.In addition,the time interval between the rainfall and the earthquake has a considerable impact on the detailed characteristics of the slope deformation,and the significant deformation occurs at the time of lowest soil strength when seepage flow reaches the lower part of the slope.Moreover,the repeated intermittent rainfall greatly affects the subsequent earthquake-induced slope deformation,the main characteristics of which are closely related to the changes in saturation and strength of the slope.However,with the prolonged time gap between each round of rainfall,the earthquake-induced slope deformation becomes insignificant.展开更多
The impact mechanism of vegetation on slope soil water infiltration and stability in the loess areas of the northeastern Qinghai-Tibet Plateau remains unclear.Understanding this mechanism is crucial for regional ecolo...The impact mechanism of vegetation on slope soil water infiltration and stability in the loess areas of the northeastern Qinghai-Tibet Plateau remains unclear.Understanding this mechanism is crucial for regional ecological restoration and shallow geological disaster prevention.This study investigated slopes covered by Caragana korshinskii Kom.by employing double-ring infiltration tests to explore the permeability characteristics and influencing factors of root-containing soils and to propose an appropriate infiltration model.Considering the synergistic effects of the canopy and roots,the hydrological response and stability of vegetation-covered slopes under rainfall infiltration conditions were evaluated through numerical simulation analysis.The results revealed that within the main root distribution layer(0-0.5 m),the initial and average infiltration rates and the permeability coefficient of the root-soil composite were significantly higher than those of bare land.Coarse roots with diameters of>5 mm were the key contributors to enhancement of the infiltration capacity.The dry density,fine particle content,and initial water content of the soil around the roots were negatively correlated with the infiltration process.The Horton model effectively reproduced the infiltration process under the canopy and on bare land.The roots significantly accelerated the advance of the slope wetting front during rainfall infiltration,whereas the canopy delayed its onset and progression.The rainfall infiltration process on vegetation-covered slopes was divided into three stages:the equilibrium infiltration stage,optimal infiltration stage beneath the canopy,and secondary equilibrium stage.Vegetation enhances slope stability through coupling of the canopy and root,with an order of canopy-root mode>root mode>bare slope.Under heavy rainfall conditions,the direct contribution of canopy interception to slope stability is limited,and its primary role is to delay the occurrence of instability.During this period,the mechanical effect of roots becomes the dominant mechanism in slope protection.展开更多
Slope units are divided according to the real topography and have clear geological characteristics,making them ideal units for evaluating the susceptibility to geological disasters.Based on the results of automaticall...Slope units are divided according to the real topography and have clear geological characteristics,making them ideal units for evaluating the susceptibility to geological disasters.Based on the results of automatically and manually corrected hydrological slope unit division,the Longhua District,Shenzhen City,Guangdong Province,was selected as the study area.A total of 15 influencing factors,namely Fluctuation,slope,slope aspect,curvature,topographic witness index(TWI),stream power index(SPI),topographic roughness index(TRI),annual average rainfall,distance to water system,engineering rock group,distance to fault,land use,normalized difference vegetation index(NDVI),nighttime light,and distance to road,were selected as evaluation indicators.The information volume model(IV)and random points were used to select non-geological disaster units,and then the random forest model(RF)was used to evaluate the susceptibility to geological disasters.The automatic slope unit and the hydrological slope unit were compared and analyzed in the random forest and information volume random forest models.The results show that the area under the curve(AUC)values of the automatic slope unit evaluation results are 0.931 for the IV-RF model and 0.716 for the RF model,which are 0.6%(IV-RF model)and 1.9%(RF model)higher than those for the hydrological slope unit.Based on a comparison of the evaluation methods based on the two types of slope units,the hydrological slope unit evaluation method based on manual correction is highly subjective,is complicated to operate,and has a low evaluation accuracy,whereas the evaluation method based on automatic slope unit division is efficient and accurate,is suitable for large-scale efficient geological disaster evaluation,and can better deal with the problem of geological disaster susceptibility evaluation.展开更多
Root-inspired anchorage systems in the field of bio-inspired geotechnics are renowned for enhancing the pullout capacity of traditional geotechnical anchorage systems by simulating the morphology and architecture of p...Root-inspired anchorage systems in the field of bio-inspired geotechnics are renowned for enhancing the pullout capacity of traditional geotechnical anchorage systems by simulating the morphology and architecture of plant root systems.However,limited studies have explored their practical applications,particularly in improving slope stability.To fill this gap,this study investigates the reinforcement effect of root-inspired anchors on slope stabilization using transparent soil modeling and 3D-printed anchors,and examines the impact of anchor branching patterns(i.e.branching numbers,branching angle,and branching nodes)on slope bearing capacity,shear band evolution,and temporal and spatial variation of slope deformation.The results show that peak slope bearing capacity increases with branching numbers and branching angles,correlating with the envelope area of the curved shear band.Upper anchors result in step-like deflections in the shear band near the trailing edge,while lower anchors convert the upward concave shear band into an upward convex one,thus increasing the slope bearing capacity.Slope deformation is minimized with intermediate branching parameters,such as a branching number of 4 and a branching angle of 45°.The anchor reinforcement mechanisms,i.e.anchor rod shear resistance,interface friction,anchor pullout capacity,and plate tightening effects,are comprehensively discussed,and the installation effects resulting from compromise slope modeling are identified as the contributors.These findings shed light on the failure process of root-inspired anchors reinforced slopes and provide a preliminary reference for potential applications,especially for the tradeoff between anchor branching,slope deformation,and slope stability.展开更多
Investigating the wind-sand flow response regularity in the longitudinal slope sections of desert highways provides a scientific basis for selecting the slope of desert roads.This study uses the Tengger Desert section...Investigating the wind-sand flow response regularity in the longitudinal slope sections of desert highways provides a scientific basis for selecting the slope of desert roads.This study uses the Tengger Desert section of the Wuhai-Maqin Expressway as a case study,employing CFD numerical simulation methods to calculate and analyze the wind-sand flow field distribution characteristics in different longitudinal slope sections.The results show that:(1)Along with the direction of the incoming flow,the windward and leeward slope toes of the embankment are low-wind-speed zones,with the wind speed at the leeward slope toe being even lower.The higher the embankment,the larger the low-wind-speed zone at the windward and leeward slope toes.As the longitudinal slope increases,the extent of the lowwind-speed zone at the same location along the route also increases.(2)Along the route direction,the wind speed at the windward and leeward slope toes decreases as embankment height increases.At the embankment toe,sand particles are transported from the top to the bottom of the longitudinal slope,and the greater the longitudinal slope,the stronger the transport effect.(3)Along the route direction,the sand accumulation around the embankment gradually gathers toward the bottom of the longitudinal slope as the slope increases.When the longitudinal slope is 3%and 4%,the trend of sand accumulation moving from the windward side at the end of the route to the leeward side at the start of the route is more significant.When the longitudinal slope is less than or equal to 3%,severe sand accumulation within the embankment range is reduced by 86.4%or more compared to when the slope is 4%.(4)Under the same longitudinal slope,the higher the embankment height,the smaller its transport rate.When the embankment height is the same,the greater the longitudinal slope,the greater the embankment transport rate.展开更多
The stability of rock slopes is frequently controlled by the initiation and propagation of inherent dominant cracks.This study systematically investigated these processes in valley slopes by combining fracture-mechani...The stability of rock slopes is frequently controlled by the initiation and propagation of inherent dominant cracks.This study systematically investigated these processes in valley slopes by combining fracture-mechanics analysis with transparent soil model tests.An analytical expression for the stress field at the dominant crack tip was derived from the slope stress distribution by superposing the corresponding stress intensity factors(SIFs).The theoretical predictions were then validated against observations from transparent soil model tests.The influences of slope angle(β),crack inclination angle(α),crack position parameter(b),and crack length parameter(h)on crack initiation and propagation were quantified.The results indicated that:(1)cracks at the slope crest tended to propagate in shear mode,and the shear crack initiation angle(θ_(s))was approximately 8°.Cracks at the slope toe might propagate in either tensile or shear mode.(2)θ_(s) at the slope crest increased withβ,b,and l,and decreased withα.The maximum change inθ_(s) induced by the considered parameters was approximately 30°.(3)The tensile crack initiation angle(θ_(t))at the slop toe decreased withβ,α,and l,while the influence of b was comparatively minor.The maximum change inθ_(t) caused by individual parameters ranged approximately from 25°to 60°.Predicted crack propagation modes and directions showed good agreement with experimental results.These findings provide theoretical guidance for stability assessments of valley slopes controlled by dominant crack propagation.展开更多
This paper presents a novel artificial intelligence(AI)-assisted two-stage method for optimising rock slope stability by integrating advanced 3D modelling with rock support design,aiming at minimising risks,material u...This paper presents a novel artificial intelligence(AI)-assisted two-stage method for optimising rock slope stability by integrating advanced 3D modelling with rock support design,aiming at minimising risks,material usage,and costs.In the first stage,an extended key block analysis identifies key blocks and key block groups,accounting for progressive failure and force interactions.The second stage uses AI algorithms to optimise rockbolting design,balancing stability,cost,and material use.The most efficient algorithms include the multi-objective tree-structured Parzen estimator(MOTPE)and non-dominated sorting genetic algorithms(NSGA-II and NSGA-III).Applied to the Larvik rock slope,the optimised solution uses 18 pre-tensioned cablebolts,providing 13.2 MN of active force and achieving a factor of safety of 1.31 while reducing the average anchorage length by approximately 16%compared to traditional design.The AI-assisted approach also reduces computation time by over 90%compared to Quasi-Monte Carlo(QMC)methods,demonstrating its efficiency for small-scale civil engineering projects and large-scale mining operations.The developed tool is practical,compatible with Building Information Modelling(BIM),and ready for engineering implementation,supporting sustainable and cost-effective rock slope stabilisation.While the method is largely automated,professional judgement remains crucial for verifying ground conditions and selecting the final solution.Future work will focus on integrating data uncertainties,addressing complex block deformation mechanisms,refining optimisation objectives,and improving the performance of multi-objective optimisation for slope rockboling applications to further enhance the method's versatility.展开更多
The identification of rock mass hazard sources is fundamental for preventing rockfall and landslide disasters in mountainous regions,with rock mass structural characteristics playing a vital role in hazard assessment....The identification of rock mass hazard sources is fundamental for preventing rockfall and landslide disasters in mountainous regions,with rock mass structural characteristics playing a vital role in hazard assessment.In this study,terrestrial laser scanning(TLS)and unmanned aerial vehicle(UAV)technologies were integrated to enhance the evaluation methodology for rock mass hazard sources,focusing on the Sichuan Yanjiang Expressway project in China.The findings demonstrate that TLS-UAV technology enhanced both spatial coverage and data density in slope modeling.Through integrated algorithmic analysis,rock discontinuities within heterogeneous datasets were systematically identified,enabling quantitative extraction and statistical analysis of key geometric parameters,including orientation,trace length,spacing,and roughness.Furthermore,quantitative models were developed for cohesion,friction angle and the morphology parameter M of in situ discontinuities,respectively,facilitating efficient mechanical parameter acquisition.A novel rock mass hazard index(RHI)was developed incorporating discontinuity geometric rating(DGR),discontinuity mechanical rating(DMR),and slope mass rating(SMR).Field validation confirmed the methodology's effectiveness in evaluating risk levels and spatial heterogeneity of rock mass hazard sources,revealing the contribution of different discontinuity sets to the rock mass hazard and identifying the primary discontinuity sets controlling instability mechanisms.This study is of great significance for evaluating discontinuity-controlled rock mass hazard sources and preventing rockfall disasters.展开更多
Slope failures,particularly in railway embankments during intense rainfall,are a major cause of economic damage and humanitarian loss.To forecast how shear cracks develop in slopes under heavy precipitation,we present...Slope failures,particularly in railway embankments during intense rainfall,are a major cause of economic damage and humanitarian loss.To forecast how shear cracks develop in slopes under heavy precipitation,we present a novel modeling framework:the Extended Cohesive Damage Element enhanced by soil moisture(SMECDE).The method first translates forecasted rainfall into soil moisture levels via an established correspondence.Then,recognizing that rainfall infiltration lowers soil cohesion—particularly at varying depths—we introduce a Soil Moisture Decoherence Model(SMDM)based on experimental data,which quantifies how cohesion degrades with moisture and how depth affects this process.By embedding SMDM within the ECDE technique,we investigate how shear fractures propagate under different moisture conditions throughout the slope profile.We apply SMECDE to a real railway embankment case to identify critical moisture thresholds and crack growth patterns.Validation is performed by comparing predictions against field measurements and weather station records,and further checked through simulations of large-scale plastic deformation in ABAQUS.展开更多
In recent years,the southwestern region of China has experienced a surge in significant mountain collapses,predominantly linked to underground mining operations.This investigation targets the Jiguanling area in Wulong...In recent years,the southwestern region of China has experienced a surge in significant mountain collapses,predominantly linked to underground mining operations.This investigation targets the Jiguanling area in Wulong,Chongqing,employing the UDEC numerical simulation technique to meticulously examine the deformation and failure characteristics,rock mass movement patterns,fracture evolution processes,and stress transmission mechanisms of anti-dip rock slopes composed of stratified rocks.These slopes are inherently susceptible to bending and tilting due to their own weight.Our findings elucidate that the predominant failure mode of anti-dip rock karst slopes is the inclined sliding(shear)type,which mirrors the fracture evolution mechanism as they extend in a quadrilateral pattern from the top and bottom plates of the mining area to the critical blocks at the rear and front edges of the slope.The disaster mechanism can be encapsulated as the"initial roof movement phase,direct roof collapse and crack propagation phase,critical block locking and sliding resistance phase,and deterioration phase".The four distinct stages of development and transformation encompass critical block slip(shear)and slope instability phases.An increase in coal seam thickness enlarges the deformation space in the lower part,while the dip angle of the coal seam influences the length and displacement range of rock fracture development.The mining sequence alters the stress failure mode of the underlying critical blocks,and the vertical height of the mining step distance modifies the potential sliding surface and failure mode of the underlying critical blocks.Ultimately,the distance between the goaf and the surface,along with the height of the mining impact,impacts the stability of the reverse slope.The results demonstrate that mining activities are the primary factor inducing the collapse of anti-dip rock slopes,with natural factors playing a secondary role.展开更多
The spatial distribution of overburden layer thickness(OLT)is crucial for landslide susceptibility prediction and slope stability analysis.Due to OLT spatial heterogeneity in hillslope regions,combined with the diffic...The spatial distribution of overburden layer thickness(OLT)is crucial for landslide susceptibility prediction and slope stability analysis.Due to OLT spatial heterogeneity in hillslope regions,combined with the difficulty and time consumption of OLT sample collection,accurately predicting OLT distribution remains a challenging.To address this,a novel framework has been developed.First,OLT samples are collected through field surveys,remote sensing,and geological drilling.Next,the heterogeneity of OLT’s spatial distribution is analyzed using the probability distribution of OLT samples and their horizontal and vertical distributions.The OLT samples are categorized and the small sample categories are expanded using the synthetic minority over-sampling technique(SMOTE).The slope position is selected as a key conditioning factor.Subsequently,16 conditioning factors are applied to construct OLT prediction model using the random forest regression algorithm.Weights are assigned to each OLT sample category to balance the uneven distribution of sample sizes.Finally,the Pearson correlation coefficient,mean absolute error(MAE),root mean square error(RMSE),and Lin’s concordance correlation coefficient(Lin’s CCC)are employed to validate the OLT prediction results.The Huangtan town serves as the case study.Results show:(1)heterogeneity analysis,SMOTE-based OLT sample expansion strategy and slope position selection can significantly mitigate the effect of spatial heterogeneity on OLT prediction.(2)The Pearson correlation coefficient,RMSE,MAE and Lin’s CCC values are 0.84,1.173,1.378 and 0.804,respectively,indicating excellent prediction performance.This research provides an effective solution for predicting OLT distribution in hillslope regions.展开更多
The coupling effects of rainfall,earthquake,and complex topographic and geological conditions complicate the dynamic responses and disasters of slope-tunnel systems.For this,the large-scale shaking table tests were ca...The coupling effects of rainfall,earthquake,and complex topographic and geological conditions complicate the dynamic responses and disasters of slope-tunnel systems.For this,the large-scale shaking table tests were carried out to explore the dynamic responses of steep bedding slope-tunnel system under the coupling effect of rainfall and earthquake.Results show that the slope surface and elevation amplification effect exhibit pronounced nonlinear change caused by the tunnel and weak interlayers.When seismic wave propagates to tunnels,the weak interlayers and rock intersecting areas present complex wave field distribution characteristics.The dynamic responses of the slope are influenced by the frequency,amplitude,and direction of seismic waves.The acceleration amplification coefficient initially rises and then falls as increasing seismic frequency,peaking at 20 Hz.Additionally,the seismic damage process of slope is categorized into elastic(2-3 m/s^(2)),elastoplastic(4-5 m/s^(2))and plastic damage stages(≥6.5 m/s^(2)).In elastic stage,ΔMPGA(ratio of acceleration amplification factor)increases with increasing seismic intensity,without obvious strain distribution change.In plastic stage,ΔMPGA begins to gradually plummet,and the strain is mainly distributed in the damaged area.The modes of seismic damage in the slope-tunnel system are mainly of tensile failure of the weak interlayer,cracking failure of tunnel lining,formation of persistent cracks on the slope crest and waist,development and outward shearing of the sliding mass,and buckling failure at the slope foot under extrusion of the upper rock body.This study can serve as a reference for predicting the failure modes of tunnel-slope system in strong seismic regions.展开更多
Vegetation plays a major role in soil protection against erosion effects,and studies have also highlighted its importance in retaining sediments from roadside slopes.Yet,hydro-sedimentological studies under natural pr...Vegetation plays a major role in soil protection against erosion effects,and studies have also highlighted its importance in retaining sediments from roadside slopes.Yet,hydro-sedimentological studies under natural precipitation conditions are still scarce in semi-arid areas due to difficulties in monitoring the few and very concentrated precipitation events.Quantifying sediment connectivity and yield at watershed scale,often highly impacted by the erosion of unpaved roads,is necessary for management plans.This study aims to evaluate the efficiency of native vegetation on roadside slope segments in Caatinga biome in retaining sediments and conserving the soil in a semi-arid area of Brazil.Surface runoff,sediment concentration,and yield measurements were measured from 34 natural precipitation events in four years on two slopes with and without vegetation.The runoff coefficients of the plot with no vegetation varied from 3.0%to 58.0%,while in the vegetated plot,they showed variation from 1.0%to 21.0%.The annual specific sediment yield ranged from 4.6 to 138.7 kg/(hm^(2)•a)for the vegetated plot and from 34.9 to 608.5 kg/(hm^(2)•a)for the unvegetated one.These results indicate a 4 to 12 times higher soil loss on the unvegetated slope in relation to the vegetated one and demonstrate that natural Caatinga vegetation acts as an effective barrier against surface-transported sediments.Moreover,natural Caatinga vegetation present on the slope plays an important role in breaking connectivity between sediment flows from unpaved roads and the watershed drainage system.These findings indicate that investments in unpaved road and roadside slope restoration,not only enhance road infrastructure but also promote environmental gains by reducing the impact of erosion.展开更多
Volcanic terrains exhibit a complex structure of pyroclastic deposits interspersed with sedimentary processes,resulting in irregular lithological sequences that lack lateral continuity and distinct stratigraphic patte...Volcanic terrains exhibit a complex structure of pyroclastic deposits interspersed with sedimentary processes,resulting in irregular lithological sequences that lack lateral continuity and distinct stratigraphic patterns.This complexity poses significant challenges for slope stability analysis,requiring the development of specialized techniques to address these issues.This research presents a numerical methodology that incorporates spatial variability,nonlinear material characterization,and probabilistic analysis using a Monte Carlo framework to address this issue.The heterogeneous structure is represented by randomly assigning different lithotypes across the slope,while maintaining predefined global proportions.This contrasts with the more common approach of applying probabilistic variability to mechanical parameters within a homogeneous slope model.The material behavior is defined using complex nonlinear failure criteria,such as the Hoek-Brown model and a parabolic model with collapse,both implemented through linearization techniques.The Discontinuity Layout Optimization(DLO)method,a novel numerical approach based on limit analysis,is employed to efficiently incorporate these advances and compute the factor of safety of the slope.Within this framework,the Monte Carlo procedure is used to assess slope stability by conducting a large number of simulations,each with a different lithotype distribution.Based on the results,a hybrid method is proposed that combines probabilistic modeling with deterministic design principles for the slope stability assessment.As a case study,the methodology is applied to a 20-m-high vertical slope composed of three lithotypes(altered scoria,welded scoria,and basalt)randomly distributed in proportions of 15%,60%,and 25%,respectively.The results show convergence of mean values after approximately 400 simulations and highlight the significant influence of spatial heterogeneity,with variations of the factor of safety between 5 and 12 in 85%of cases.They also reveal non-circular and mid-slope failure wedges not captured by traditional stability methods.Finally,an equivalent normal probability distribution is proposed as a reliable approximation of the factor of safety for use in risk analysis and engineering decision-making.展开更多
The instability and failure of high rock slopes have a significant impact on the safe mining operations.Therefore,revealing the instability mechanism of high rock slopes is of great research significance.This paper ai...The instability and failure of high rock slopes have a significant impact on the safe mining operations.Therefore,revealing the instability mechanism of high rock slopes is of great research significance.This paper aims to reveal the instability mechanism of high rock slopes through physical model tests and numerical simulations.Taking the slope failure on the west side of Pit 1 of Husab Uranium Mine in Namibia in 2021 as the research background,a physical model of the high rock slope of Husab Uranium Mine was established by combining with on-site geological data.The experimental system was monitored by a GoPro camera,a CCD camera,and strain sensors.The damage evolution process of the high rock slope model was analyzed,and numerical simulation verification was carried out using Flac 3D software.Thus,the instability mechanism of the slope failure in this open-pit mine was revealed from multiple perspectives.The results show that the instability mechanism of the high rock slope was determined through the evolution of the displacement field and strain field during the model excavation process,as well as the deformation characteristics of the images at the time of instability and failure.The slope deformation process can be divided into four stages:the initial inter-layer dislocation stage,the crack generation stage,the crack propagation stage,and the crack penetration and failure stage.The results of the model experiment and numerical simulation confirm the consistency between the failure mode of the model slope and the actual slope failure on-site,providing guidance for the prevention and control projects of similar types of mine failures.展开更多
基金funded by the Key Research and Development Projects in Xinjiang Uygur Autonomous Region(2022B03024-3)the Xinjiang Uygur Autonomous Region Central Leading Local Science and Technology Development Fund Project(ZYYD2024CG20)the Autonomous Region'Tianshan Talents'Training Program Young Top Talents Project(2023TSYCJU0007).
文摘The banks in the middle and lower reaches of the Tarim River in China are weak in erosion resistance and prone to collapse.Vegetation,as a natural reinforcement material,can effectively improve slope stability and curb soil erosion.In March and July 2023,a field survey was conducted on the types and distribution characteristics of vegetation along both banks of a certain section in the lower reaches of the Tarim River.Taking COMSOL Multiphysics as the finite element numerical simulation platform,we investigated the variation law of bank slope stability in the middle and lower reaches of the Tarim River under different root morphologies,considering changes in transpiration time,rainfall,and water level under the action of hydro-mechanical reinforcement.The findings showed that vegetation transpiration has a significant effect on soil pore water pressure.Given the same transpiration rate,shorter root systems produced greater pore water pressure.For equal root lengths,the pore water pressures generated by roots in exponential and triangular morphologies were significantly greater than those generated by roots in uniformly distributed and parabolic morphologies.The water absorption capacity of the root system increased with transpiration rate.After 7 d of transpiration,the maximum safety factor of the bank slope reinforced by exponential roots was 1.568,which was a 9.88%improvement over that of the bare slope.After 24 h of rainfall,the effect of vegetation transpiration on soil pore water pressure weakened rapidly;the pore water pressure of the surface soil generated by transpiration from vegetation with different root morphologies was concentrated near–10.00 kPa.After rainfall,the displacement of the exponential root reinforced slope was minimized to 0.137 m.The effect of transpiration-induced changes in substrate suction on slope stability was negligible during the rainfall period.Compared with that of the bare slope,the displacements of bank slopes reinforced by root systems significantly increased.The maximum displacement occurred when the water level changed by 1.5 m/d;the displacement of the bare slope was 0.554 m,whereas the displacements of bank slopes reinforced by roots in different morphologies were 0.260–0.273 m.The impact of vegetation transpiration on the safety factor of riverbanks under sudden water level drops was relatively minor,but it can enhance the stability of riverbanks to a certain extent.Among these,riverbanks reinforced by roots in triangular and exponential morphologies exhibited superior stability compared with those reinforced by uniformly distributed or parabolic root systems.The findings offer a theoretical basis and practical guidance for designing vegetation slope protection in the middle and lower reaches of the Tarim River.
基金funded by the National Natural Science Foundation of China(Grant No.72504262)Natural Science Foundation of Hubei Province of China(Grant No.2024AFB102)。
文摘As demand for land resources is rapidly growing nowadays,developing on slope lands has become a way to relieve pressure on flat lands.Although some studies use the concept of slope spectrum to explore the trend of land use upslope,relying solely on the slope spectrum is too broad and prevents deeper research.Therefore,using China's land use and DEM data from 2000 to 2020,our study integrated the slope spectrum and the slope sensitivity coefficient(SSC)calculated by the land use transfer matrix as a new approach and method for understanding the underlying formations and impacts of upslope in farmland and construction land,supporting regional management strategies.The results show that:1)Farmlands were upslope in the South and developed horizontally in the North,and construction lands were upslope nationwide.2)Using the land use transfer matrix and SSC,we classified farmland upslope as passive and active patterns,and construction land upslope as saturation and avoidance patterns based on their land use transfer mechanisms in slope space.Provinces with passive and saturation patterns are mainly located near the east coast.3)Different patterns of upslope have distinct impacts on sustainable development.The passive pattern harms food security while the active pattern can relieve pressure on food security but increases ecological risks.Saturation pattern damages food security,ecological protection,and city livability,but avoidance pattern can promote food security and ecological protection.The findings will serve as an essential reference for developing land use strategies aimed at sustainable development.
基金supported by the project of the National Natural Science Foundation of China entitled“Distribution and change characteristics of construction land on slope gradient in mountainous cities of southern China”(No.41961039)。
文摘China's requisition-compensation balance strategy has dramatically reshaped cropland spatial patterns,drawing multidisciplinary research attention.However,existing studies predominantly emphasize horizontal distribution,overlooking the significant influence of slope gradient on cropland spatial patterns.This paper proposes a slope location quotient(SLQ)index that reflects the relative advantage of cropland distribution and explores the slope grade difference of cropland spatial patterns in China at the county scale.The analysis adopts 30-m resolution digital elevation model with land cover data,taking 2672 counties with cropland ratio>1%as study units.The temporal scope covers 1990 and 2020,with slope gradients categorized into five grades:0°~2°,2°~6°,6°~15°,15°~25°,and 25°~90°.Results show that:1)The inverse correlation between cropland area and slope gradient remained stable throughout the study period,with the variation in cropland area frequency across slope grades being less than 1%.2)The spatial patterns of SLQ in 1990 and 2020 both transited stepwise with slope gradient,while≤2°and>6°slopes exhibited opposing patterns.3)The mean absolute variation of SLQ during 1990-2020 increased with slope gradient(R2=0.926,p<0.01).Particularly for slope grades>15°,the mean absolute variation reached 0.26(for 15°~25°)and 0.43(for 25°~90°),respectively,and displayed a distinct southward-increasing and northwarddecreasing pattern.This study offers novel slopegradient perspectives for analyzing cropland spatial patterns.To enhance cropland protection benefits,reversing the steep cropland SLQ surge in southern China is recommended.
文摘Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybrid control method was proposed.This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative(PID)controller.The speed of agricultural machinery was influenced by longitudinal forces,which were divided into two parts:one part was slope-related forces and conventional resistance,and the other was hard-to-estimate forces,such as sliding friction.For the first part,a slope-based controller was designed;for the second part,a PID controller was implemented.By combining these two controllers,the system can dynamically adjust the throttle opening and the brake master cylinder pressure,ensuring steady speed travel on sloping farmland.Simulation tests at a target speed of 7 km/h demonstrated that the proposed controller maintained a stable speed,achieving a root mean square error of 0.13 km/h and a mean absolute percentage error of 1.6%.Field tests on a practical experimental platform validated the method’s effectiveness,with results showing consistent control performance across varying slope conditions.The proposed controller demonstrated superior control performance.Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed,meeting the stability requirements for agricultural operations.
基金supported by the Chongqing Water Conservancy Science and Technology Project(grant number:CQSLK-202329)the Natural Science Foundation of Chongqing,China(grant number:CSTB2022NSCQ-MSX0991)+1 种基金the National Natural Science Foundation of China(grant number:52378327)the Chongqing Natural Science Foundation Innovation Development Joint Fund(grant number:CSTB2022NSCQ-LZX0049)。
文摘Rock slope instability is a prevalent geological hazard that imposes significant adverse impacts on engineering activities.Although existing studies have focused on homogeneous rock slopes,the theoretical models for quantifying the stability of softhard interbedded anti-inclined slopes remain underdeveloped,primarily due to the complex force transfer mechanisms involved.This study proposed a novel theoretical model for the stability analysis of soft-hard interbedded anti-inclined slopes under rainfall conditions.The framework models stratified rock layers as layered cantilever beams with material heterogeneity.Based on the principle of deformation compatibility,it comprehensively accounted for interlayer force transfer and strength degradation resulting from differential deformations among rock layers.Furthermore,it integrated the critical instability length induced by the self-weight of rock layers to determine the fracture depth.The proposed method was validated against engineering case studies and physical model tests,with error falling within an acceptable range.Compared to existing theoretical methods,the proposed method provided a more realistic representation of the slope's stress field.The analysis results demonstrate that rainfall not only reduces the inclination angle of the failure surface but also leads to an approximate 30%decrease in the safety factor.The proposed theoretical model is particularly useful for quickly calculating the stability of soft-hard interbedded anti-inclined rock slope under rainfall conditions,compared to complex and time-consuming numerical simulation calculations.
基金supported by the China Postdoctoral Science Foundation(CPSF)(Grant No.2024M762769)the Natural Science Basic Research Program of Shaanxi(Grant No.2024JC-YBQN-0333)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20232230).
文摘Slopes are likely to fail in areas with frequent rainfall and earthquakes.The deformation characteristics of unsaturated slopes subjected to post-rainfall earthquakes are investigated using centrifuge model tests and finite element analyses.Three tests of the slope deformation under earthquake and post-rainfall earthquakes are first studied using image analysis techniques.Then,based on an elastoplastic constitutive model,numerical simulations are carried out using the finite element method and compared with the centrifuge test results.Finally,a parametric study is performed to clarify the effects of antecedent rainfall on earthquake-induced slope deformation.The results show that slope deformation caused by post-rainfall earthquakes differs from that caused by earthquakes without antecedent rainfall.The seepage flow and soil strength of the slope are affected by previous rainfall conditions,such as intensity and duration,which directly influence the slope deformation caused by the subsequent earthquake.Soil displacement and strain become greater and the slip surface is more noticeable during the post-rainfall earthquake of higher intensity.In addition,the time interval between the rainfall and the earthquake has a considerable impact on the detailed characteristics of the slope deformation,and the significant deformation occurs at the time of lowest soil strength when seepage flow reaches the lower part of the slope.Moreover,the repeated intermittent rainfall greatly affects the subsequent earthquake-induced slope deformation,the main characteristics of which are closely related to the changes in saturation and strength of the slope.However,with the prolonged time gap between each round of rainfall,the earthquake-induced slope deformation becomes insignificant.
基金funded by Science and Technology Program of Qinghai Province of China(2024-SF-129)the National Natural Science Foundation of China(42002283).
文摘The impact mechanism of vegetation on slope soil water infiltration and stability in the loess areas of the northeastern Qinghai-Tibet Plateau remains unclear.Understanding this mechanism is crucial for regional ecological restoration and shallow geological disaster prevention.This study investigated slopes covered by Caragana korshinskii Kom.by employing double-ring infiltration tests to explore the permeability characteristics and influencing factors of root-containing soils and to propose an appropriate infiltration model.Considering the synergistic effects of the canopy and roots,the hydrological response and stability of vegetation-covered slopes under rainfall infiltration conditions were evaluated through numerical simulation analysis.The results revealed that within the main root distribution layer(0-0.5 m),the initial and average infiltration rates and the permeability coefficient of the root-soil composite were significantly higher than those of bare land.Coarse roots with diameters of>5 mm were the key contributors to enhancement of the infiltration capacity.The dry density,fine particle content,and initial water content of the soil around the roots were negatively correlated with the infiltration process.The Horton model effectively reproduced the infiltration process under the canopy and on bare land.The roots significantly accelerated the advance of the slope wetting front during rainfall infiltration,whereas the canopy delayed its onset and progression.The rainfall infiltration process on vegetation-covered slopes was divided into three stages:the equilibrium infiltration stage,optimal infiltration stage beneath the canopy,and secondary equilibrium stage.Vegetation enhances slope stability through coupling of the canopy and root,with an order of canopy-root mode>root mode>bare slope.Under heavy rainfall conditions,the direct contribution of canopy interception to slope stability is limited,and its primary role is to delay the occurrence of instability.During this period,the mechanical effect of roots becomes the dominant mechanism in slope protection.
文摘Slope units are divided according to the real topography and have clear geological characteristics,making them ideal units for evaluating the susceptibility to geological disasters.Based on the results of automatically and manually corrected hydrological slope unit division,the Longhua District,Shenzhen City,Guangdong Province,was selected as the study area.A total of 15 influencing factors,namely Fluctuation,slope,slope aspect,curvature,topographic witness index(TWI),stream power index(SPI),topographic roughness index(TRI),annual average rainfall,distance to water system,engineering rock group,distance to fault,land use,normalized difference vegetation index(NDVI),nighttime light,and distance to road,were selected as evaluation indicators.The information volume model(IV)and random points were used to select non-geological disaster units,and then the random forest model(RF)was used to evaluate the susceptibility to geological disasters.The automatic slope unit and the hydrological slope unit were compared and analyzed in the random forest and information volume random forest models.The results show that the area under the curve(AUC)values of the automatic slope unit evaluation results are 0.931 for the IV-RF model and 0.716 for the RF model,which are 0.6%(IV-RF model)and 1.9%(RF model)higher than those for the hydrological slope unit.Based on a comparison of the evaluation methods based on the two types of slope units,the hydrological slope unit evaluation method based on manual correction is highly subjective,is complicated to operate,and has a low evaluation accuracy,whereas the evaluation method based on automatic slope unit division is efficient and accurate,is suitable for large-scale efficient geological disaster evaluation,and can better deal with the problem of geological disaster susceptibility evaluation.
基金supported by the High-end Foreign Expert Introduction Program(Grant No.G2022165004L)the Sichuan Transportation Science and Technology Project(Grant No.2018-ZL-01)China Railway 20th Bureau Science and Technology Project(Grant No.YF1900SD07B).
文摘Root-inspired anchorage systems in the field of bio-inspired geotechnics are renowned for enhancing the pullout capacity of traditional geotechnical anchorage systems by simulating the morphology and architecture of plant root systems.However,limited studies have explored their practical applications,particularly in improving slope stability.To fill this gap,this study investigates the reinforcement effect of root-inspired anchors on slope stabilization using transparent soil modeling and 3D-printed anchors,and examines the impact of anchor branching patterns(i.e.branching numbers,branching angle,and branching nodes)on slope bearing capacity,shear band evolution,and temporal and spatial variation of slope deformation.The results show that peak slope bearing capacity increases with branching numbers and branching angles,correlating with the envelope area of the curved shear band.Upper anchors result in step-like deflections in the shear band near the trailing edge,while lower anchors convert the upward concave shear band into an upward convex one,thus increasing the slope bearing capacity.Slope deformation is minimized with intermediate branching parameters,such as a branching number of 4 and a branching angle of 45°.The anchor reinforcement mechanisms,i.e.anchor rod shear resistance,interface friction,anchor pullout capacity,and plate tightening effects,are comprehensively discussed,and the installation effects resulting from compromise slope modeling are identified as the contributors.These findings shed light on the failure process of root-inspired anchors reinforced slopes and provide a preliminary reference for potential applications,especially for the tradeoff between anchor branching,slope deformation,and slope stability.
基金financially supported by Youth Science“Research on Failure Mechanism and Evaluation Method of Sand Control Measures for Railway Machinery in Sandy Area”(12302511)Ningxia Transportation Department Science and Technology Project(20200173)The Central Guidance on Local Science and Technology Development Funds(22ZY1QA005)。
文摘Investigating the wind-sand flow response regularity in the longitudinal slope sections of desert highways provides a scientific basis for selecting the slope of desert roads.This study uses the Tengger Desert section of the Wuhai-Maqin Expressway as a case study,employing CFD numerical simulation methods to calculate and analyze the wind-sand flow field distribution characteristics in different longitudinal slope sections.The results show that:(1)Along with the direction of the incoming flow,the windward and leeward slope toes of the embankment are low-wind-speed zones,with the wind speed at the leeward slope toe being even lower.The higher the embankment,the larger the low-wind-speed zone at the windward and leeward slope toes.As the longitudinal slope increases,the extent of the lowwind-speed zone at the same location along the route also increases.(2)Along the route direction,the wind speed at the windward and leeward slope toes decreases as embankment height increases.At the embankment toe,sand particles are transported from the top to the bottom of the longitudinal slope,and the greater the longitudinal slope,the stronger the transport effect.(3)Along the route direction,the sand accumulation around the embankment gradually gathers toward the bottom of the longitudinal slope as the slope increases.When the longitudinal slope is 3%and 4%,the trend of sand accumulation moving from the windward side at the end of the route to the leeward side at the start of the route is more significant.When the longitudinal slope is less than or equal to 3%,severe sand accumulation within the embankment range is reduced by 86.4%or more compared to when the slope is 4%.(4)Under the same longitudinal slope,the higher the embankment height,the smaller its transport rate.When the embankment height is the same,the greater the longitudinal slope,the greater the embankment transport rate.
基金financially supported by the National Nature Science Foundation of China(Nos.52379110 and 42207222)the Key Technologies for Accurate Diagnosis and Intelligent Prevention and Control of Slope Hazards in Open Pit Mines,181 Major R&D projects of Metallurgical Corporation of China Ltd。
文摘The stability of rock slopes is frequently controlled by the initiation and propagation of inherent dominant cracks.This study systematically investigated these processes in valley slopes by combining fracture-mechanics analysis with transparent soil model tests.An analytical expression for the stress field at the dominant crack tip was derived from the slope stress distribution by superposing the corresponding stress intensity factors(SIFs).The theoretical predictions were then validated against observations from transparent soil model tests.The influences of slope angle(β),crack inclination angle(α),crack position parameter(b),and crack length parameter(h)on crack initiation and propagation were quantified.The results indicated that:(1)cracks at the slope crest tended to propagate in shear mode,and the shear crack initiation angle(θ_(s))was approximately 8°.Cracks at the slope toe might propagate in either tensile or shear mode.(2)θ_(s) at the slope crest increased withβ,b,and l,and decreased withα.The maximum change inθ_(s) induced by the considered parameters was approximately 30°.(3)The tensile crack initiation angle(θ_(t))at the slop toe decreased withβ,α,and l,while the influence of b was comparatively minor.The maximum change inθ_(t) caused by individual parameters ranged approximately from 25°to 60°.Predicted crack propagation modes and directions showed good agreement with experimental results.These findings provide theoretical guidance for stability assessments of valley slopes controlled by dominant crack propagation.
基金support from Research Council of Norway via STIPINST PhD grant(Grant No.323307),Bever Control AS,and Bane NOR.
文摘This paper presents a novel artificial intelligence(AI)-assisted two-stage method for optimising rock slope stability by integrating advanced 3D modelling with rock support design,aiming at minimising risks,material usage,and costs.In the first stage,an extended key block analysis identifies key blocks and key block groups,accounting for progressive failure and force interactions.The second stage uses AI algorithms to optimise rockbolting design,balancing stability,cost,and material use.The most efficient algorithms include the multi-objective tree-structured Parzen estimator(MOTPE)and non-dominated sorting genetic algorithms(NSGA-II and NSGA-III).Applied to the Larvik rock slope,the optimised solution uses 18 pre-tensioned cablebolts,providing 13.2 MN of active force and achieving a factor of safety of 1.31 while reducing the average anchorage length by approximately 16%compared to traditional design.The AI-assisted approach also reduces computation time by over 90%compared to Quasi-Monte Carlo(QMC)methods,demonstrating its efficiency for small-scale civil engineering projects and large-scale mining operations.The developed tool is practical,compatible with Building Information Modelling(BIM),and ready for engineering implementation,supporting sustainable and cost-effective rock slope stabilisation.While the method is largely automated,professional judgement remains crucial for verifying ground conditions and selecting the final solution.Future work will focus on integrating data uncertainties,addressing complex block deformation mechanisms,refining optimisation objectives,and improving the performance of multi-objective optimisation for slope rockboling applications to further enhance the method's versatility.
基金support from the National Natural Science Foundation of China(Grant Nos.42177142 and 52378477)the Key Research and Development Program of Shaanxi(Grant No.2023-YBSF-486).
文摘The identification of rock mass hazard sources is fundamental for preventing rockfall and landslide disasters in mountainous regions,with rock mass structural characteristics playing a vital role in hazard assessment.In this study,terrestrial laser scanning(TLS)and unmanned aerial vehicle(UAV)technologies were integrated to enhance the evaluation methodology for rock mass hazard sources,focusing on the Sichuan Yanjiang Expressway project in China.The findings demonstrate that TLS-UAV technology enhanced both spatial coverage and data density in slope modeling.Through integrated algorithmic analysis,rock discontinuities within heterogeneous datasets were systematically identified,enabling quantitative extraction and statistical analysis of key geometric parameters,including orientation,trace length,spacing,and roughness.Furthermore,quantitative models were developed for cohesion,friction angle and the morphology parameter M of in situ discontinuities,respectively,facilitating efficient mechanical parameter acquisition.A novel rock mass hazard index(RHI)was developed incorporating discontinuity geometric rating(DGR),discontinuity mechanical rating(DMR),and slope mass rating(SMR).Field validation confirmed the methodology's effectiveness in evaluating risk levels and spatial heterogeneity of rock mass hazard sources,revealing the contribution of different discontinuity sets to the rock mass hazard and identifying the primary discontinuity sets controlling instability mechanisms.This study is of great significance for evaluating discontinuity-controlled rock mass hazard sources and preventing rockfall disasters.
文摘Slope failures,particularly in railway embankments during intense rainfall,are a major cause of economic damage and humanitarian loss.To forecast how shear cracks develop in slopes under heavy precipitation,we present a novel modeling framework:the Extended Cohesive Damage Element enhanced by soil moisture(SMECDE).The method first translates forecasted rainfall into soil moisture levels via an established correspondence.Then,recognizing that rainfall infiltration lowers soil cohesion—particularly at varying depths—we introduce a Soil Moisture Decoherence Model(SMDM)based on experimental data,which quantifies how cohesion degrades with moisture and how depth affects this process.By embedding SMDM within the ECDE technique,we investigate how shear fractures propagate under different moisture conditions throughout the slope profile.We apply SMECDE to a real railway embankment case to identify critical moisture thresholds and crack growth patterns.Validation is performed by comparing predictions against field measurements and weather station records,and further checked through simulations of large-scale plastic deformation in ABAQUS.
基金supported by the National Natural Science Foundation of China(No.52474092,52074042)National Key Research and Development Program of China(No.2018YFC1504802)。
文摘In recent years,the southwestern region of China has experienced a surge in significant mountain collapses,predominantly linked to underground mining operations.This investigation targets the Jiguanling area in Wulong,Chongqing,employing the UDEC numerical simulation technique to meticulously examine the deformation and failure characteristics,rock mass movement patterns,fracture evolution processes,and stress transmission mechanisms of anti-dip rock slopes composed of stratified rocks.These slopes are inherently susceptible to bending and tilting due to their own weight.Our findings elucidate that the predominant failure mode of anti-dip rock karst slopes is the inclined sliding(shear)type,which mirrors the fracture evolution mechanism as they extend in a quadrilateral pattern from the top and bottom plates of the mining area to the critical blocks at the rear and front edges of the slope.The disaster mechanism can be encapsulated as the"initial roof movement phase,direct roof collapse and crack propagation phase,critical block locking and sliding resistance phase,and deterioration phase".The four distinct stages of development and transformation encompass critical block slip(shear)and slope instability phases.An increase in coal seam thickness enlarges the deformation space in the lower part,while the dip angle of the coal seam influences the length and displacement range of rock fracture development.The mining sequence alters the stress failure mode of the underlying critical blocks,and the vertical height of the mining step distance modifies the potential sliding surface and failure mode of the underlying critical blocks.Ultimately,the distance between the goaf and the surface,along with the height of the mining impact,impacts the stability of the reverse slope.The results demonstrate that mining activities are the primary factor inducing the collapse of anti-dip rock slopes,with natural factors playing a secondary role.
基金funded by the Natural Science Foundation of China(No.42407241,42272326 and 52222905)Jiangxi Provincial Natural Science Foundation(Nos.20242BAB20241,20242BAB23052 and 20242BAB24001).
文摘The spatial distribution of overburden layer thickness(OLT)is crucial for landslide susceptibility prediction and slope stability analysis.Due to OLT spatial heterogeneity in hillslope regions,combined with the difficulty and time consumption of OLT sample collection,accurately predicting OLT distribution remains a challenging.To address this,a novel framework has been developed.First,OLT samples are collected through field surveys,remote sensing,and geological drilling.Next,the heterogeneity of OLT’s spatial distribution is analyzed using the probability distribution of OLT samples and their horizontal and vertical distributions.The OLT samples are categorized and the small sample categories are expanded using the synthetic minority over-sampling technique(SMOTE).The slope position is selected as a key conditioning factor.Subsequently,16 conditioning factors are applied to construct OLT prediction model using the random forest regression algorithm.Weights are assigned to each OLT sample category to balance the uneven distribution of sample sizes.Finally,the Pearson correlation coefficient,mean absolute error(MAE),root mean square error(RMSE),and Lin’s concordance correlation coefficient(Lin’s CCC)are employed to validate the OLT prediction results.The Huangtan town serves as the case study.Results show:(1)heterogeneity analysis,SMOTE-based OLT sample expansion strategy and slope position selection can significantly mitigate the effect of spatial heterogeneity on OLT prediction.(2)The Pearson correlation coefficient,RMSE,MAE and Lin’s CCC values are 0.84,1.173,1.378 and 0.804,respectively,indicating excellent prediction performance.This research provides an effective solution for predicting OLT distribution in hillslope regions.
基金supported by the National Natural Science Foundation of China (Grant No.52109125)the Natural Science Foundation of Jiangsu Province,China (Grant No.BK20231217)the Key Laboratory of Geomechanics and Geotechnical Engineering Safety,Chinese Academy of Sciences (Grant No.SKLGME023001).
文摘The coupling effects of rainfall,earthquake,and complex topographic and geological conditions complicate the dynamic responses and disasters of slope-tunnel systems.For this,the large-scale shaking table tests were carried out to explore the dynamic responses of steep bedding slope-tunnel system under the coupling effect of rainfall and earthquake.Results show that the slope surface and elevation amplification effect exhibit pronounced nonlinear change caused by the tunnel and weak interlayers.When seismic wave propagates to tunnels,the weak interlayers and rock intersecting areas present complex wave field distribution characteristics.The dynamic responses of the slope are influenced by the frequency,amplitude,and direction of seismic waves.The acceleration amplification coefficient initially rises and then falls as increasing seismic frequency,peaking at 20 Hz.Additionally,the seismic damage process of slope is categorized into elastic(2-3 m/s^(2)),elastoplastic(4-5 m/s^(2))and plastic damage stages(≥6.5 m/s^(2)).In elastic stage,ΔMPGA(ratio of acceleration amplification factor)increases with increasing seismic intensity,without obvious strain distribution change.In plastic stage,ΔMPGA begins to gradually plummet,and the strain is mainly distributed in the damaged area.The modes of seismic damage in the slope-tunnel system are mainly of tensile failure of the weak interlayer,cracking failure of tunnel lining,formation of persistent cracks on the slope crest and waist,development and outward shearing of the sliding mass,and buckling failure at the slope foot under extrusion of the upper rock body.This study can serve as a reference for predicting the failure modes of tunnel-slope system in strong seismic regions.
基金the National Council for Scientific and Technological Development (CNPq) for funding the field studies and for the research productivity fellowship (CNPq/PQ) awarded to Pedro Henrique Augusto MEDEIROS and José Carlos de ARAúJOthe Coordination for the Improvement of Higher Education Personnel (CAPES) for the doctoral scholarship awarded to Teresa Raquel Lima FARIAS (2117/13-4)the Foundation for the Support of Scientific and Technological Development in the State of Ceará (FUNCAP) for the master scholarship awarded to Maria Thereza Rocha CHAVES。
文摘Vegetation plays a major role in soil protection against erosion effects,and studies have also highlighted its importance in retaining sediments from roadside slopes.Yet,hydro-sedimentological studies under natural precipitation conditions are still scarce in semi-arid areas due to difficulties in monitoring the few and very concentrated precipitation events.Quantifying sediment connectivity and yield at watershed scale,often highly impacted by the erosion of unpaved roads,is necessary for management plans.This study aims to evaluate the efficiency of native vegetation on roadside slope segments in Caatinga biome in retaining sediments and conserving the soil in a semi-arid area of Brazil.Surface runoff,sediment concentration,and yield measurements were measured from 34 natural precipitation events in four years on two slopes with and without vegetation.The runoff coefficients of the plot with no vegetation varied from 3.0%to 58.0%,while in the vegetated plot,they showed variation from 1.0%to 21.0%.The annual specific sediment yield ranged from 4.6 to 138.7 kg/(hm^(2)•a)for the vegetated plot and from 34.9 to 608.5 kg/(hm^(2)•a)for the unvegetated one.These results indicate a 4 to 12 times higher soil loss on the unvegetated slope in relation to the vegetated one and demonstrate that natural Caatinga vegetation acts as an effective barrier against surface-transported sediments.Moreover,natural Caatinga vegetation present on the slope plays an important role in breaking connectivity between sediment flows from unpaved roads and the watershed drainage system.These findings indicate that investments in unpaved road and roadside slope restoration,not only enhance road infrastructure but also promote environmental gains by reducing the impact of erosion.
基金the project PID2022-139202OB-I00Neural Networks and Optimization Techniques for the Design and Safe Maintenance of Transportation Infrastructures:Volcanic Rock Geotechnics and Slope Stability(IA-Pyroslope),funded by the Spanish State Research Agency of the Ministry of Science,Innovation and Universities of Spain and the European Regional Development Fund,MCIN/AEI/10.13039/501100011033/FEDER,EU。
文摘Volcanic terrains exhibit a complex structure of pyroclastic deposits interspersed with sedimentary processes,resulting in irregular lithological sequences that lack lateral continuity and distinct stratigraphic patterns.This complexity poses significant challenges for slope stability analysis,requiring the development of specialized techniques to address these issues.This research presents a numerical methodology that incorporates spatial variability,nonlinear material characterization,and probabilistic analysis using a Monte Carlo framework to address this issue.The heterogeneous structure is represented by randomly assigning different lithotypes across the slope,while maintaining predefined global proportions.This contrasts with the more common approach of applying probabilistic variability to mechanical parameters within a homogeneous slope model.The material behavior is defined using complex nonlinear failure criteria,such as the Hoek-Brown model and a parabolic model with collapse,both implemented through linearization techniques.The Discontinuity Layout Optimization(DLO)method,a novel numerical approach based on limit analysis,is employed to efficiently incorporate these advances and compute the factor of safety of the slope.Within this framework,the Monte Carlo procedure is used to assess slope stability by conducting a large number of simulations,each with a different lithotype distribution.Based on the results,a hybrid method is proposed that combines probabilistic modeling with deterministic design principles for the slope stability assessment.As a case study,the methodology is applied to a 20-m-high vertical slope composed of three lithotypes(altered scoria,welded scoria,and basalt)randomly distributed in proportions of 15%,60%,and 25%,respectively.The results show convergence of mean values after approximately 400 simulations and highlight the significant influence of spatial heterogeneity,with variations of the factor of safety between 5 and 12 in 85%of cases.They also reveal non-circular and mid-slope failure wedges not captured by traditional stability methods.Finally,an equivalent normal probability distribution is proposed as a reliable approximation of the factor of safety for use in risk analysis and engineering decision-making.
文摘The instability and failure of high rock slopes have a significant impact on the safe mining operations.Therefore,revealing the instability mechanism of high rock slopes is of great research significance.This paper aims to reveal the instability mechanism of high rock slopes through physical model tests and numerical simulations.Taking the slope failure on the west side of Pit 1 of Husab Uranium Mine in Namibia in 2021 as the research background,a physical model of the high rock slope of Husab Uranium Mine was established by combining with on-site geological data.The experimental system was monitored by a GoPro camera,a CCD camera,and strain sensors.The damage evolution process of the high rock slope model was analyzed,and numerical simulation verification was carried out using Flac 3D software.Thus,the instability mechanism of the slope failure in this open-pit mine was revealed from multiple perspectives.The results show that the instability mechanism of the high rock slope was determined through the evolution of the displacement field and strain field during the model excavation process,as well as the deformation characteristics of the images at the time of instability and failure.The slope deformation process can be divided into four stages:the initial inter-layer dislocation stage,the crack generation stage,the crack propagation stage,and the crack penetration and failure stage.The results of the model experiment and numerical simulation confirm the consistency between the failure mode of the model slope and the actual slope failure on-site,providing guidance for the prevention and control projects of similar types of mine failures.
