Excavation-induced deformations of earth-retaining walls(ERWs)can critically affect the safety of surrounding structures,highlighting the need for reliable prediction models to support timely decision-making during co...Excavation-induced deformations of earth-retaining walls(ERWs)can critically affect the safety of surrounding structures,highlighting the need for reliable prediction models to support timely decision-making during construction.This study utilizes traditional statistical ARIMA(Auto-Regressive Integrated Moving Average)and deep learning-based LSTM(Long Short-Term Memory)models to predict earth-retaining walls deformation using inclinometer data from excavation sites and compares the predictive performance of both models.The ARIMA model demonstrates strengths in analyzing linear patterns in time-series data as it progresses over time,whereas LSTM exhibits superior capabilities in capturing complex non-linear patterns and long-term dependencies within the time series data.This research includes preprocessing of measurement data for inclinometer,performance evaluation based on various time series data lengths and input variable conditions,and demonstrates that the LSTM model offers statistically significant improvements in predictive performance over the ARIMA model.In addition,by combining LSTM with attention mechanism,attention-based LSTM(ATLSTM)is proposed to improve the short-and long-term prediction performance and solve the problem of excavation site domain change.This study presents the advantages and disadvantages of major time series analysis models for the stability evaluation of mud walls using geotechnical inclinometer data from excavation sites,and suggests that time series analysis models can be used effectively through comparative experiments.展开更多
Retaining walls are utilized to support the earth and prevent the soil from spreading with natural slope angles where there are differences in the elevation of ground surfaces.As the need for retaining structures incr...Retaining walls are utilized to support the earth and prevent the soil from spreading with natural slope angles where there are differences in the elevation of ground surfaces.As the need for retaining structures increases,the use of retaining walls is increasing.The retaining walls,which increase the stability of levels,are economical and meet existing adverse conditions.A considerable amount of retaining walls is made from steel-reinforced concrete.The construction of reinforced concrete retaining walls can be costly due to its components.For this reason,the optimum cost should be targeted in the design of retaining walls.This study presents an artificial neural network(ANN)model developed to predict the optimum dimensions of a retaining wall using soil properties,material properties,and external loading conditions.The dataset utilized to train the ANN model is generated with the Flower Pollination Algorithm.The target variables in the dataset are the length of the heel(y1),length of the toe(y2),thickness of the stem(top)(y3),thickness of the stem(bottom)(y4),foundation base thickness(y5)and cost(y6)and these are estimated by utilizing an ANN model based on the height of the wall(x1),material unit weight(x2),wall friction angle(x3),surcharge load(x4),concrete cost per m3(x5),steel cost per ton(x6)and the soil class(x7).The model is formulated and trained as a multi-output regression model,as all outputs are numeric and continuous.The training and evaluation of the model results in a high prediction performance(R20.99).In addition,the impacts of different input features on the model>predictions are revealed using the SHapley Additive exPlanations(SHAP)algorithm.The study demonstrates that when trained with a large dataset,ANN models perform very well by predicting the optimal cost with high performance.展开更多
Gob-side entry retaining(GER)is widely applied in China.Nevertheless,the stability mechanism of the GER with coal pilla r-backfill body(CPBB)under dynamic overburden load remains unexplored.A voussoir beam structure(V...Gob-side entry retaining(GER)is widely applied in China.Nevertheless,the stability mechanism of the GER with coal pilla r-backfill body(CPBB)under dynamic overburden load remains unexplored.A voussoir beam structure(VBS)model is established to analyze roof structure stability during panel advancement,introducing a VBS stability criterion.Reducing block B length l and immediate roof damage variable D,and increasing coal pillar widthχ_(c).lowers the GER structure instability risk.Reducing l and the GER width w leads to a CPBB system stability upswing.A UDEC model was established to systematically reveal how the l,backfill body width x_(b),and strength affect the stability and coupling performance of the CPPB system by monitoring the crack damage D_(C).Simulation results indicate that at l=14 m,χ_(b)=2.0 m,watercement ratio 1.5:1,the coal pillar and backfill body have similar D_(C)but maintain stability,resulting in CPPB system coupling degree K,better.A novel GER method supported by the CPBB was implemented on-site.Monitoring results indicated that the coal pillar peak stresses were 19.17 MPa(ahead),16.14 MPa(behind),and the backfill body peak stress was 12.27 MPa(maximum).The floor heave was380 mm,with a 103 mm backfill body rib.展开更多
The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as diff...The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent.In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed.First,the composite hard roof cutting short cantilever beam(SCB)model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently,the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue.The control technology was finally verified through onsite engineering experiments in terms of composite hard roof.The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway.The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6,respectively,and the maximum and average working resistances of the working face support decreased by 10.9%and 13.8%,respectively.Consequently,the deformations of reserved entry decreased,and entry steadiness was enhanced.The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.展开更多
This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcr...This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcritical dynamics.The nonlinear governing equations for the FGM pipe are derived by the extended Hamilton's principle,and subsequently discretized through the application of the Galerkin method.The direct method of multi-scales is then used to solve the derived equations.A thorough analysis of various parameters,including the clip stiffness,the power-law index,the porosity,and the clip location,is conducted to gain a comprehensive understanding of the system's nonlinear dynamics.Through the analysis of the first natural frequency,the study highlights the influence of the flow velocity and the clip stiffness,while the comparisons with metallic pipes emphasize the role of FGM composition.The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index,offering valuable insights into the system's nonlinear resonant behavior.Furthermore,the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness,revealing nuanced effects on the system response and resonance characteristics.This comprehensive analysis enhances the understanding of nonlinear behaviors in FGM porous pipes with a retaining clip,providing key insights for practical engineering applications in system design and optimization.展开更多
A general analytical method to calculate the passive rigid retaining wall pressure was deduced considering all displacement modes. First, the general displacement mode function was setup, then the hypotheses were made...A general analytical method to calculate the passive rigid retaining wall pressure was deduced considering all displacement modes. First, the general displacement mode function was setup, then the hypotheses were made that the lateral passive pressure is linear to the corresponding horizontal displacement and the soil behind retaining wall is composed of a set of springs and ideal rigid plasticity body, the general analytical method was proposed to calculate the passive rigid retaining wall pressure based on Coulomb theory. The analytical results show that the resultant forces of the passive earth pressure are equal to those of Coulomb＇s theory, but the distribution of the passive pressure and the position of the resultant force depend on the passive displacement mode parameter, and the former is a parabolic function of the soil depth. The analytical results are also in good agreement with the experimental ones.展开更多
[Objective] The aim was to reduce fertilizer and water losses caused by surface runoffs in rainy season and provide scientific references for soil moisture in arid season. [Method] The application proportion of comple...[Objective] The aim was to reduce fertilizer and water losses caused by surface runoffs in rainy season and provide scientific references for soil moisture in arid season. [Method] The application proportion of complex water-holding organic materials was determined by multi-factor mixture experiment and the curve changes of soil moisture characters were tested to analyze water-holding capacity and water availability of soils. [Result] The initial moisture content of soil with different mixture proportions improved in varying degrees. For example, when water-retention agents reached 0.4% and 0.6% of soil weight, soil moisture contents were 69.0% and70.5%, respectively, which showed significant differences with the control（S0.0）. Soil dehydration terms in different treatments all extended, prolonging in the range of4.6-14 d. [Conclusion] The applications of water-retention agent and organic material would improve water-holding capacity of hills and low mountains, and initial moisture content and dehydration cycle tend to be volatile upon mixture proportion. Therefore,it is necessary to adjust soil fertility, crop species, and irrigation to meet crop demands on fertilizer and water.展开更多
This paper describes the development of an expert system(ES) on earth retaining structures for the selection and design.The ES retaining is an interactive menudriven system and consists of two main parts—the selectio...This paper describes the development of an expert system(ES) on earth retaining structures for the selection and design.The ES retaining is an interactive menudriven system and consists of two main parts—the selection part,selectwall and the design part.Selectwall is developed using the knowledge base and it makes a choice of the most appropriate retaining structure.The design part is developed by three independent subprograms which perform detailed design including strength,deformation,stability of the retaining structure.The calculation results are illustrated by plotting the diagram.Using this program,the design procedure of the retaining structure can be performed automatically.展开更多
This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical engineering: spread footing and retaining wall. Several recent advanced optimization metho...This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical engineering: spread footing and retaining wall. Several recent advanced optimization methods have been developed, but very few of these methods have been applied to geotechnical problems. The current research develops a modified particle swarm optimization (MPSO) approach to obtain the optimum design of spread footing and retaining wall. The algorithm handles the problem-specific constraints using a penalty function approach. The optimization procedure controls all geotechnical and structural design constraints while reducing the overall cost of the structures. To verify the effectiveness and robustness of the proposed algorithm, three case studies of spread footing and retaining wall are illustrated. Comparison of the results of the present method, standard PSO, and other selected methods employed in previous studies shows the reliability and accuracy of the algorithm. Moreover, the parametric performance is investigated in order to examine the effect of relevant variables on the optimum design of the footing and the retaining structure utilizing the proposed method.展开更多
Floor heave is the most common convergence in gob-side entry retaining.The paper analyzes the form,process and characteristics of gob-side entry retaining with the comprehensive methods of theoretical analysis,numeric...Floor heave is the most common convergence in gob-side entry retaining.The paper analyzes the form,process and characteristics of gob-side entry retaining with the comprehensive methods of theoretical analysis,numerical simulation and the field trial.Research results present that bending and folding floor heave is the main factor in the stage of the first panel mining;squeezing and fluidity floor heave plays a great role in the stable stage of gob-side entry retaining;the combination of the former two factors affects mainly the stage of the second mining ahead;abutment pressure is a fundamental contribution to the serious floor heave of gob-side entry retaining,and sides corners of solid coal body are key part in the case of floor heave controlling of gob-side entry retaining.Floor heave of gob-side entry retaining can be significantly controlled by reinforcing sides and corners of solid coal body,and influence rules on the floor heave of gob side entry retaining of sides supporting strength and the bottom bolt orientation in solid coal side are obtained.Research results have been successfully applied in gob-side entry retaining of G20-F23070 face haulage roadway in #2 coal mine of Pingmei Group,and the field observation shows that the proposed technique is an effective way in controlling the floor heave of gob-side entry retaining.展开更多
In order to reduce the errors of the reliability of the retaining wall structure in the establishment of function, in the estimation of parameter and algorithm, firstly, two new reliability and stability models of ant...In order to reduce the errors of the reliability of the retaining wall structure in the establishment of function, in the estimation of parameter and algorithm, firstly, two new reliability and stability models of anti-slipping and anti-overturning based on the upper-bound theory of limit analysis were established, and two kinds of failure modes were regarded as a series of systems with multiple correlated failure modes. Then, statistical characteristics of parameters of the retaining wall structure were inferred by maximal entropy principle. At last, the structural reliabilities of single failure mode and multiple failure modes were calculated by Monte Carlo method in MATLAB and the results were compared and analyzed on the sensitivity. It indicates that this method, with a high precision, is not only easy to program and quick in calculation, but also without the limit of nonlinear functions and non-normal random variables. And the results calculated by this method which applies both the limit analysis theory, maximal entropy principle and Monte Carlo method into analyzing the reliability of the retaining wall structures is more scientific, accurate and reliable, in comparison with those calculated by traditional method.展开更多
This paper analyzed the water-retention mechanism of feldspathic sandstone （fine-（〈 1 mm diam.） and gravel-sized （2-3 cm diam.） in Mu Us Sandy Land, Northwest China. The objective of this study is to study the e...This paper analyzed the water-retention mechanism of feldspathic sandstone （fine-（〈 1 mm diam.） and gravel-sized （2-3 cm diam.） in Mu Us Sandy Land, Northwest China. The objective of this study is to study the effect of feldspathic sandstone amendment on water retention in sandy land. The results showed that as the proportion of fine feldspathic sandstone in the sandy land soil increased, the soil texture changed from sand to silt loam, the capillary po- rosity gradually increased from 26.3% to 44.9%, and the soil saturated hydraulic conductivity decreased from 7.10 ram/rain to 0.07 mm/min. Feldspathic sandstone gravel formed micro-reservoirs in the sandy land soil, playing the role of a ＇water absorbent＇ and ＇water retaining agent＇ in sandy land. Amendment with feldspathic sandstone can increase water retention in the arable layer of sandy land by 67%. This study provides a theoretical basis for the amelioration of sandy land on a large scale. It can be concluded that amendment with feldspathic sandstone can improve the physical properties of sandy land soil and increase soil water retention.展开更多
To investigate the seismic response of the steel-strip reinforced soil retaining wall with fullheight rigid facing in terms of the acceleration in the backfill, dynamic earth pressure in the backfill, the displacement...To investigate the seismic response of the steel-strip reinforced soil retaining wall with fullheight rigid facing in terms of the acceleration in the backfill, dynamic earth pressure in the backfill, the displacements on the facing and the dynamic reinforcement strain distribution under different peak acceleration, a large 1-g shaking table test was performed on a reduced-scale reinforced-earth retaining wall model. It was observed that the acceleration response in non-strip region is greater than that in potential fracture region which is similar with the stability region under small earthquake,while the acceleration response in potential fracture region is greater than that in stability region in middle-upper of the wall under moderately strong earthquakes. The potential failure model of the rigid wall is rotating around the wall toe. It also was discovered that the Fourier spectra produced by the inputting white noises after seismic wave presents double peaks, rather than original single peak, and the frequency of the second peak trends to increase with increasing the PGA(peak ground amplitude) of the excitation which is greater than 0.4 g. Additionally,the non-liner distribution of strip strain along the strips was observed, and the distribution trend was not constant in different row. Soil pressure peak value in stability region is larger than that in potential fracture region. The wall was effective under 0.1 g-0.3 g seismic wave according to the analyses of the facing displacement and relative density. Also, it was discovered that the potential failure surface is corresponds to that in design code, but the area is larger. The results from the study can provide guidance for a more rational design of reinforced earth retaining walls with full-height rigid facing in the earthquake zone.展开更多
Given the extensive utilization of cantilever retaining walls in construction and development projects,their optimal design and analysis with proper attention to seismic loads is a typical engineering problem.This res...Given the extensive utilization of cantilever retaining walls in construction and development projects,their optimal design and analysis with proper attention to seismic loads is a typical engineering problem.This research presents a new algorithm for pseudo-static analysis of retaining walls employing upper bound method.The algorithm can be utilized to design and check the external and internal stability of the wall based on the proposed mechanism.One of the main features of this algorithm is its ability to determine the critical condition of failure wedges,the minimum safety factor and maximum force acting on the wall,as well as the minimum weight of the wall,simultaneously,by effectively using the multi-objective optimization.The results obtained by the proposed failure mechanisms show that,while using the upper bound limit analysis approach,the active force should be maximized concurrent with optimizing the direction of the plane passing through the back of the heel.The present study also applies the proposed algorithm to determine the critical direction of the earthquake acceleration coefficient.The critical direction of earthquake acceleration coefficient is defined as the direction that maximizes the active force exerted on the wall and minimizes the safety factor for wall stability.The results obtained in this study are in good agreement with those of similar studies carried out based on the limit equilibrium method and finite element analysis.The critical failure mechanisms were determined via optimization with genetic algorithm.展开更多
This study investigated the influence factors on the seismic response and deformation modes of retaining walls using large-scale model shaking table tests. Experimental results showed that the distribution of peak sei...This study investigated the influence factors on the seismic response and deformation modes of retaining walls using large-scale model shaking table tests. Experimental results showed that the distribution of peak seismic earth pressures along the height of a wall was a single peak value curve. The seismic earth pressures on a gravel soil retaining wall were larger than the pressures on the weathered granite and quartz retaining walls. Also, the peak seismic earth pressure increased with increases in the peak ground acceleration and the wall height. The measured seismic active earth pressures on a rock foundation retaining wall were larger than the calculated values, and the action position of resultant seismic pressure was higher than 0.33 H. In the soil foundation retaining wall, the measured seismic earth pressures were much smaller than the calculated values, while the action position was slightly higher than 0.33 H. The soil foundation retaining wall suffered base sliding and overturning under earthquake conditions, while overturning was the main failure mode for the rock foundation retaining walls.展开更多
Based on the active failure mechanism and passive failure mechanism for a pressurized tunnel face, the analytical solutions of the minimum collapse pressure and maximum blowout pressure that could maintain the stabili...Based on the active failure mechanism and passive failure mechanism for a pressurized tunnel face, the analytical solutions of the minimum collapse pressure and maximum blowout pressure that could maintain the stability of pressurized tunnel faces were deduced using limit analysis in conjunction with nonlinear failure criterion under the condition of pore water pressure. Due to the objective existence of the parameter randomness of soil, the statistical properties of random variables were determined by the maximum entropy principle, and the Monte Carlo method was employed to calculate the failure probability of a pressurized tunnel. The results show that the randomness of soil parameters exerts great influence on the stability of a pressurized tunnel, which indicates that the research should be done on the topic of determination of statistical distribution for geotechnical parameters and the level of variability. For the failure probability of a pressurized tunnel under multiple failure modes, the corresponding safe retaining pressures and optimal range of safe retaining pressures are calculated by introducing allowable failure probability and minimum allowable failure probability. The results can provide practical use in the pressurized tunnel engineering.展开更多
Mn18Cr18N, the high-nitrogen steel, is the 2nd generation material for manufacturing the retaining ring of firepower generators. In this paper, the hot deformation behavior of the material was investigated by thermo-m...Mn18Cr18N, the high-nitrogen steel, is the 2nd generation material for manufacturing the retaining ring of firepower generators. In this paper, the hot deformation behavior of the material was investigated by thermo-mechanical modeling tests. And the flow stress curves of the steel were obtained for various combinations of the temperature and strain rate. Based on the results of the tests, the complex forming process of a retaining ring including punching, expanding and extrusion with an enclosure was put forward and simulated by means of numerical simulation method. The results indicate that the process is a novel and force-saved practical technology for manufacturing heavy retaining rings.展开更多
Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side en...Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side entry retaining are obtained via physical simulation and theoretical analysis,in which the scope of disturbed strata is enlarged from main roof to fracture zone.The experiment reveals that as a working face advances,roof strata sequentially collapse from bottom to top and produce multiple disturbances to gob-side entry retaining.Key strata among the overlying strata control each collapse.Main roof subsidence is divided into three stages:flexure subsidence prior to rupture,rotational subsidence during rupture and compressive subsidence after rupture.The amounts of deformation evident in each of the three stages are 15%,55%and 30%,respectively.After the master stratum collapses,main roof subsidence approaches its maximum value.The final span of the key stratum determines the moment and cycling of gob-side entry retaining disturbances.Main roof subsidence influences the load on the filling wall.The sequential roof collapse of overlying strata results in fluctuations in the gob-side entry retaining deformation.Calculation formulae for the final span of the key stratum and the filling wall load are obtained via theoretical analysis.A control method for the stability of the gob-side entry retaining’s surrounding rock is proposed,which includes 3 measures:a“dual-layer”proactive anchorage support,roadside filling with dynamic strength matching and auxiliary support during disturbance.Finally,the gob-side entry retaining of the Xiaoqing mine E1403 working face is presented as an engineering case capable of verifying the validity of the research conclusions.展开更多
With the increasing maturity of automatic driving technology,the homogeneous traffic flow will gradually evolve into the heterogeneous traffic flow,which consists of human-driving and autonomous vehicles.To better stu...With the increasing maturity of automatic driving technology,the homogeneous traffic flow will gradually evolve into the heterogeneous traffic flow,which consists of human-driving and autonomous vehicles.To better study the characteristics of the heterogeneous traffic system,this paper proposes a new car-following model for autonomous vehicles and heterogeneous traffic flow,which considers the self-stabilizing effect of vehicles.Through linear and nonlinear methods,this paper deduces and analyzes the stability of such a car-following model with the self-stabilizing effect.Finally,the model is verified by numerical simulation.Numerical results show that the self-stabilizing effect can make the heterogeneous traffic flow more stable,and that increasing the self-stabilizing coefficient or historical time length can strengthen the stability of heterogeneous traffic flow and alleviate traffic congestion effectively.In addition,the heterogeneous traffic flow can also be stabilized with a higher proportion of autonomous vehicles.展开更多
This study investigates the stability problem of gob-side entry retaining （GER） and backfilling wall which located under the key block B. Based on the combined research of elastic-plastic mechanics, structure mechan...This study investigates the stability problem of gob-side entry retaining （GER） and backfilling wall which located under the key block B. Based on the combined research of elastic-plastic mechanics, structure mechanics and modern theory of mining-induced pressure, the caving characteristic and roof structure over the GER were analyzed, and the vertical force and the torque on retained entry roof were also derived as the position for the retained entry varies. On the basis of the specific geology in Huainan mining area, the results indicate that a relatively more stable position for retained entry neighbors the hinge point of block A and B, and it also located at a scope ranging from this point to the one-third length of block B in horizontal direction. As to appropriate position for backfilling wall, this study recommends partial- road-in backfilling method for GER. Field trial conducted at panel face 12418 of Xieqiao Mine demonstrates that the recommended width for original entry is 3.6 m and the preferred width proportion between original retained entry and original entry is 75 % or so whereas the avoidable one is 88 % or so. These findings provide qualitative references to the mines which share similar geology as what Huainan mining area characterized.展开更多
基金carried out under the KICT Research Program(Project No.20250285-001,Development of Infrastructure Disaster Prevention Technology Based on Satellites SAR)funded by the Ministry of Science and ICT.
文摘Excavation-induced deformations of earth-retaining walls(ERWs)can critically affect the safety of surrounding structures,highlighting the need for reliable prediction models to support timely decision-making during construction.This study utilizes traditional statistical ARIMA(Auto-Regressive Integrated Moving Average)and deep learning-based LSTM(Long Short-Term Memory)models to predict earth-retaining walls deformation using inclinometer data from excavation sites and compares the predictive performance of both models.The ARIMA model demonstrates strengths in analyzing linear patterns in time-series data as it progresses over time,whereas LSTM exhibits superior capabilities in capturing complex non-linear patterns and long-term dependencies within the time series data.This research includes preprocessing of measurement data for inclinometer,performance evaluation based on various time series data lengths and input variable conditions,and demonstrates that the LSTM model offers statistically significant improvements in predictive performance over the ARIMA model.In addition,by combining LSTM with attention mechanism,attention-based LSTM(ATLSTM)is proposed to improve the short-and long-term prediction performance and solve the problem of excavation site domain change.This study presents the advantages and disadvantages of major time series analysis models for the stability evaluation of mud walls using geotechnical inclinometer data from excavation sites,and suggests that time series analysis models can be used effectively through comparative experiments.
文摘Retaining walls are utilized to support the earth and prevent the soil from spreading with natural slope angles where there are differences in the elevation of ground surfaces.As the need for retaining structures increases,the use of retaining walls is increasing.The retaining walls,which increase the stability of levels,are economical and meet existing adverse conditions.A considerable amount of retaining walls is made from steel-reinforced concrete.The construction of reinforced concrete retaining walls can be costly due to its components.For this reason,the optimum cost should be targeted in the design of retaining walls.This study presents an artificial neural network(ANN)model developed to predict the optimum dimensions of a retaining wall using soil properties,material properties,and external loading conditions.The dataset utilized to train the ANN model is generated with the Flower Pollination Algorithm.The target variables in the dataset are the length of the heel(y1),length of the toe(y2),thickness of the stem(top)(y3),thickness of the stem(bottom)(y4),foundation base thickness(y5)and cost(y6)and these are estimated by utilizing an ANN model based on the height of the wall(x1),material unit weight(x2),wall friction angle(x3),surcharge load(x4),concrete cost per m3(x5),steel cost per ton(x6)and the soil class(x7).The model is formulated and trained as a multi-output regression model,as all outputs are numeric and continuous.The training and evaluation of the model results in a high prediction performance(R20.99).In addition,the impacts of different input features on the model>predictions are revealed using the SHapley Additive exPlanations(SHAP)algorithm.The study demonstrates that when trained with a large dataset,ANN models perform very well by predicting the optimal cost with high performance.
基金financial support provided by the National Natural Science Foundation of China(Nos.52574126and 52574144)the Xinjiang Uygur Autonomous Region Key R&D Project Task Special-Department and Department Linkage Project(No.2022B01051)+4 种基金the Major Project of Regional Joint Foundation of China(No.U21A20107)the Xinjiang Uygur Autonomous Region Tianchi Introduction Plan(No.2024XGYTCYC03)the Scientific Research Fund of Hunan Provincial Education Department(No.24A0359)the Urumqi City Hongshan Sci-Tech Innvoation Elite Talents Youth Top Talents Program(No.B241013004)the National Key Research and Development Program Young Scientists Project(No.2024YFC2910600)。
文摘Gob-side entry retaining(GER)is widely applied in China.Nevertheless,the stability mechanism of the GER with coal pilla r-backfill body(CPBB)under dynamic overburden load remains unexplored.A voussoir beam structure(VBS)model is established to analyze roof structure stability during panel advancement,introducing a VBS stability criterion.Reducing block B length l and immediate roof damage variable D,and increasing coal pillar widthχ_(c).lowers the GER structure instability risk.Reducing l and the GER width w leads to a CPBB system stability upswing.A UDEC model was established to systematically reveal how the l,backfill body width x_(b),and strength affect the stability and coupling performance of the CPPB system by monitoring the crack damage D_(C).Simulation results indicate that at l=14 m,χ_(b)=2.0 m,watercement ratio 1.5:1,the coal pillar and backfill body have similar D_(C)but maintain stability,resulting in CPPB system coupling degree K,better.A novel GER method supported by the CPBB was implemented on-site.Monitoring results indicated that the coal pillar peak stresses were 19.17 MPa(ahead),16.14 MPa(behind),and the backfill body peak stress was 12.27 MPa(maximum).The floor heave was380 mm,with a 103 mm backfill body rib.
基金This work described herein was supported by the Program of China Scholarship Council(202206430008)the National Natural Science Foundation of China(NSFC)(52074300 and 52304111)+1 种基金the Yueqi Young Scholars Project of China University of Mining and Technology Beijing(2602021RC84)the Guizhou province science and technology planning project([2020]3007 and[2020]2Y019).
文摘The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent.In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed.First,the composite hard roof cutting short cantilever beam(SCB)model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently,the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue.The control technology was finally verified through onsite engineering experiments in terms of composite hard roof.The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway.The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6,respectively,and the maximum and average working resistances of the working face support decreased by 10.9%and 13.8%,respectively.Consequently,the deformations of reserved entry decreased,and entry steadiness was enhanced.The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.
文摘This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcritical dynamics.The nonlinear governing equations for the FGM pipe are derived by the extended Hamilton's principle,and subsequently discretized through the application of the Galerkin method.The direct method of multi-scales is then used to solve the derived equations.A thorough analysis of various parameters,including the clip stiffness,the power-law index,the porosity,and the clip location,is conducted to gain a comprehensive understanding of the system's nonlinear dynamics.Through the analysis of the first natural frequency,the study highlights the influence of the flow velocity and the clip stiffness,while the comparisons with metallic pipes emphasize the role of FGM composition.The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index,offering valuable insights into the system's nonlinear resonant behavior.Furthermore,the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness,revealing nuanced effects on the system response and resonance characteristics.This comprehensive analysis enhances the understanding of nonlinear behaviors in FGM porous pipes with a retaining clip,providing key insights for practical engineering applications in system design and optimization.
基金Project (201012200094) supported by the Freedom Exploration Program of Central South University of ChinaProject (20090461022) supported by the China Postdoctoral Science FoundationProject (2010ZJ05) supported by the Science and Technology supporting Program of Xinjiang Production and Construction Corps in China
文摘A general analytical method to calculate the passive rigid retaining wall pressure was deduced considering all displacement modes. First, the general displacement mode function was setup, then the hypotheses were made that the lateral passive pressure is linear to the corresponding horizontal displacement and the soil behind retaining wall is composed of a set of springs and ideal rigid plasticity body, the general analytical method was proposed to calculate the passive rigid retaining wall pressure based on Coulomb theory. The analytical results show that the resultant forces of the passive earth pressure are equal to those of Coulomb＇s theory, but the distribution of the passive pressure and the position of the resultant force depend on the passive displacement mode parameter, and the former is a parabolic function of the soil depth. The analytical results are also in good agreement with the experimental ones.
基金Supported by Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(CX(14)2099)~~
文摘[Objective] The aim was to reduce fertilizer and water losses caused by surface runoffs in rainy season and provide scientific references for soil moisture in arid season. [Method] The application proportion of complex water-holding organic materials was determined by multi-factor mixture experiment and the curve changes of soil moisture characters were tested to analyze water-holding capacity and water availability of soils. [Result] The initial moisture content of soil with different mixture proportions improved in varying degrees. For example, when water-retention agents reached 0.4% and 0.6% of soil weight, soil moisture contents were 69.0% and70.5%, respectively, which showed significant differences with the control（S0.0）. Soil dehydration terms in different treatments all extended, prolonging in the range of4.6-14 d. [Conclusion] The applications of water-retention agent and organic material would improve water-holding capacity of hills and low mountains, and initial moisture content and dehydration cycle tend to be volatile upon mixture proportion. Therefore,it is necessary to adjust soil fertility, crop species, and irrigation to meet crop demands on fertilizer and water.
文摘This paper describes the development of an expert system(ES) on earth retaining structures for the selection and design.The ES retaining is an interactive menudriven system and consists of two main parts—the selection part,selectwall and the design part.Selectwall is developed using the knowledge base and it makes a choice of the most appropriate retaining structure.The design part is developed by three independent subprograms which perform detailed design including strength,deformation,stability of the retaining structure.The calculation results are illustrated by plotting the diagram.Using this program,the design procedure of the retaining structure can be performed automatically.
文摘This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical engineering: spread footing and retaining wall. Several recent advanced optimization methods have been developed, but very few of these methods have been applied to geotechnical problems. The current research develops a modified particle swarm optimization (MPSO) approach to obtain the optimum design of spread footing and retaining wall. The algorithm handles the problem-specific constraints using a penalty function approach. The optimization procedure controls all geotechnical and structural design constraints while reducing the overall cost of the structures. To verify the effectiveness and robustness of the proposed algorithm, three case studies of spread footing and retaining wall are illustrated. Comparison of the results of the present method, standard PSO, and other selected methods employed in previous studies shows the reliability and accuracy of the algorithm. Moreover, the parametric performance is investigated in order to examine the effect of relevant variables on the optimum design of the footing and the retaining structure utilizing the proposed method.
基金provided by the National Natural Science Foundation of China(No.51174195)the State Key Laboratory of Coal Resources and Mine Safety of China University of Mining and Technology(No.SKLCRSM08X04)+1 种基金a foundation for the author of the National Excellent Doctoral Dissertation of China(No.200760)the Science Research Fund of China University of Mining and Technology(No.2008A002)
文摘Floor heave is the most common convergence in gob-side entry retaining.The paper analyzes the form,process and characteristics of gob-side entry retaining with the comprehensive methods of theoretical analysis,numerical simulation and the field trial.Research results present that bending and folding floor heave is the main factor in the stage of the first panel mining;squeezing and fluidity floor heave plays a great role in the stable stage of gob-side entry retaining;the combination of the former two factors affects mainly the stage of the second mining ahead;abutment pressure is a fundamental contribution to the serious floor heave of gob-side entry retaining,and sides corners of solid coal body are key part in the case of floor heave controlling of gob-side entry retaining.Floor heave of gob-side entry retaining can be significantly controlled by reinforcing sides and corners of solid coal body,and influence rules on the floor heave of gob side entry retaining of sides supporting strength and the bottom bolt orientation in solid coal side are obtained.Research results have been successfully applied in gob-side entry retaining of G20-F23070 face haulage roadway in #2 coal mine of Pingmei Group,and the field observation shows that the proposed technique is an effective way in controlling the floor heave of gob-side entry retaining.
基金Project(2013CB036004) supported by the National Basic Research Program of ChinaProjects(51178468,51174086) supported by the National Natural Science Foundation of ChinaProject(201102) supported by the Open Foundation of Hunan Key Laboratory of Safe Mining Techniques of Coal Mines,China
文摘In order to reduce the errors of the reliability of the retaining wall structure in the establishment of function, in the estimation of parameter and algorithm, firstly, two new reliability and stability models of anti-slipping and anti-overturning based on the upper-bound theory of limit analysis were established, and two kinds of failure modes were regarded as a series of systems with multiple correlated failure modes. Then, statistical characteristics of parameters of the retaining wall structure were inferred by maximal entropy principle. At last, the structural reliabilities of single failure mode and multiple failure modes were calculated by Monte Carlo method in MATLAB and the results were compared and analyzed on the sensitivity. It indicates that this method, with a high precision, is not only easy to program and quick in calculation, but also without the limit of nonlinear functions and non-normal random variables. And the results calculated by this method which applies both the limit analysis theory, maximal entropy principle and Monte Carlo method into analyzing the reliability of the retaining wall structures is more scientific, accurate and reliable, in comparison with those calculated by traditional method.
基金Under the auspices of Key Direction Program of Chinese Academy of Science(No.KZCX2-YW-Q06-03)MajorState Basic Research Development Program of China(No.2009CB421103)+1 种基金National Natural Science Foundation of China(No.41001050)Major Science and Technology Program for Water Pollution Control and Treatment(No.2012ZX07201004)
文摘This paper analyzed the water-retention mechanism of feldspathic sandstone （fine-（〈 1 mm diam.） and gravel-sized （2-3 cm diam.） in Mu Us Sandy Land, Northwest China. The objective of this study is to study the effect of feldspathic sandstone amendment on water retention in sandy land. The results showed that as the proportion of fine feldspathic sandstone in the sandy land soil increased, the soil texture changed from sand to silt loam, the capillary po- rosity gradually increased from 26.3% to 44.9%, and the soil saturated hydraulic conductivity decreased from 7.10 ram/rain to 0.07 mm/min. Feldspathic sandstone gravel formed micro-reservoirs in the sandy land soil, playing the role of a ＇water absorbent＇ and ＇water retaining agent＇ in sandy land. Amendment with feldspathic sandstone can increase water retention in the arable layer of sandy land by 67%. This study provides a theoretical basis for the amelioration of sandy land on a large scale. It can be concluded that amendment with feldspathic sandstone can improve the physical properties of sandy land soil and increase soil water retention.
基金founded by the National Natural Science Foundation of China(Grant No.51708163)Research Program of the Ministry of Transport of the People’s Republic of China(Grant No.2013318800020)Doctoral Innovation Fund Program of Southwest Jiaotong University(Grant No.D-CX201703)
文摘To investigate the seismic response of the steel-strip reinforced soil retaining wall with fullheight rigid facing in terms of the acceleration in the backfill, dynamic earth pressure in the backfill, the displacements on the facing and the dynamic reinforcement strain distribution under different peak acceleration, a large 1-g shaking table test was performed on a reduced-scale reinforced-earth retaining wall model. It was observed that the acceleration response in non-strip region is greater than that in potential fracture region which is similar with the stability region under small earthquake,while the acceleration response in potential fracture region is greater than that in stability region in middle-upper of the wall under moderately strong earthquakes. The potential failure model of the rigid wall is rotating around the wall toe. It also was discovered that the Fourier spectra produced by the inputting white noises after seismic wave presents double peaks, rather than original single peak, and the frequency of the second peak trends to increase with increasing the PGA(peak ground amplitude) of the excitation which is greater than 0.4 g. Additionally,the non-liner distribution of strip strain along the strips was observed, and the distribution trend was not constant in different row. Soil pressure peak value in stability region is larger than that in potential fracture region. The wall was effective under 0.1 g-0.3 g seismic wave according to the analyses of the facing displacement and relative density. Also, it was discovered that the potential failure surface is corresponds to that in design code, but the area is larger. The results from the study can provide guidance for a more rational design of reinforced earth retaining walls with full-height rigid facing in the earthquake zone.
文摘Given the extensive utilization of cantilever retaining walls in construction and development projects,their optimal design and analysis with proper attention to seismic loads is a typical engineering problem.This research presents a new algorithm for pseudo-static analysis of retaining walls employing upper bound method.The algorithm can be utilized to design and check the external and internal stability of the wall based on the proposed mechanism.One of the main features of this algorithm is its ability to determine the critical condition of failure wedges,the minimum safety factor and maximum force acting on the wall,as well as the minimum weight of the wall,simultaneously,by effectively using the multi-objective optimization.The results obtained by the proposed failure mechanisms show that,while using the upper bound limit analysis approach,the active force should be maximized concurrent with optimizing the direction of the plane passing through the back of the heel.The present study also applies the proposed algorithm to determine the critical direction of the earthquake acceleration coefficient.The critical direction of earthquake acceleration coefficient is defined as the direction that maximizes the active force exerted on the wall and minimizes the safety factor for wall stability.The results obtained in this study are in good agreement with those of similar studies carried out based on the limit equilibrium method and finite element analysis.The critical failure mechanisms were determined via optimization with genetic algorithm.
基金the National Program on Key Research Project of China (Grant No. 2016YFC0802206)the open research fund of MOE Key Laboratory of High-speed Railway Engineering,Southwest Jiaotong University and Doctoral Innovation Fund Program of Southwest University of Science and Technology (Grant No. 16zx7123)
文摘This study investigated the influence factors on the seismic response and deformation modes of retaining walls using large-scale model shaking table tests. Experimental results showed that the distribution of peak seismic earth pressures along the height of a wall was a single peak value curve. The seismic earth pressures on a gravel soil retaining wall were larger than the pressures on the weathered granite and quartz retaining walls. Also, the peak seismic earth pressure increased with increases in the peak ground acceleration and the wall height. The measured seismic active earth pressures on a rock foundation retaining wall were larger than the calculated values, and the action position of resultant seismic pressure was higher than 0.33 H. In the soil foundation retaining wall, the measured seismic earth pressures were much smaller than the calculated values, while the action position was slightly higher than 0.33 H. The soil foundation retaining wall suffered base sliding and overturning under earthquake conditions, while overturning was the main failure mode for the rock foundation retaining walls.
基金Project(2013CB036004)supported by the National Basic Research Program of ChinaProject(51378510)supported by the National Natural Science Foundation of China
文摘Based on the active failure mechanism and passive failure mechanism for a pressurized tunnel face, the analytical solutions of the minimum collapse pressure and maximum blowout pressure that could maintain the stability of pressurized tunnel faces were deduced using limit analysis in conjunction with nonlinear failure criterion under the condition of pore water pressure. Due to the objective existence of the parameter randomness of soil, the statistical properties of random variables were determined by the maximum entropy principle, and the Monte Carlo method was employed to calculate the failure probability of a pressurized tunnel. The results show that the randomness of soil parameters exerts great influence on the stability of a pressurized tunnel, which indicates that the research should be done on the topic of determination of statistical distribution for geotechnical parameters and the level of variability. For the failure probability of a pressurized tunnel under multiple failure modes, the corresponding safe retaining pressures and optimal range of safe retaining pressures are calculated by introducing allowable failure probability and minimum allowable failure probability. The results can provide practical use in the pressurized tunnel engineering.
文摘Mn18Cr18N, the high-nitrogen steel, is the 2nd generation material for manufacturing the retaining ring of firepower generators. In this paper, the hot deformation behavior of the material was investigated by thermo-mechanical modeling tests. And the flow stress curves of the steel were obtained for various combinations of the temperature and strain rate. Based on the results of the tests, the complex forming process of a retaining ring including punching, expanding and extrusion with an enclosure was put forward and simulated by means of numerical simulation method. The results indicate that the process is a novel and force-saved practical technology for manufacturing heavy retaining rings.
基金Project(51404251)supported by the National Natural Science Foundation of ChinaProject(BK20140198)supported by the Natural Science Foundation of Jiangsu Province,China+1 种基金Project(PPZY2015A046)supported by the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side entry retaining are obtained via physical simulation and theoretical analysis,in which the scope of disturbed strata is enlarged from main roof to fracture zone.The experiment reveals that as a working face advances,roof strata sequentially collapse from bottom to top and produce multiple disturbances to gob-side entry retaining.Key strata among the overlying strata control each collapse.Main roof subsidence is divided into three stages:flexure subsidence prior to rupture,rotational subsidence during rupture and compressive subsidence after rupture.The amounts of deformation evident in each of the three stages are 15%,55%and 30%,respectively.After the master stratum collapses,main roof subsidence approaches its maximum value.The final span of the key stratum determines the moment and cycling of gob-side entry retaining disturbances.Main roof subsidence influences the load on the filling wall.The sequential roof collapse of overlying strata results in fluctuations in the gob-side entry retaining deformation.Calculation formulae for the final span of the key stratum and the filling wall load are obtained via theoretical analysis.A control method for the stability of the gob-side entry retaining’s surrounding rock is proposed,which includes 3 measures:a“dual-layer”proactive anchorage support,roadside filling with dynamic strength matching and auxiliary support during disturbance.Finally,the gob-side entry retaining of the Xiaoqing mine E1403 working face is presented as an engineering case capable of verifying the validity of the research conclusions.
基金supported by the National Natural Science Foundation of China(Grant No.61773243)the Major Technology Innovation Project of Shandong Province,China(Grant No.2019TSLH0203)the National Key Research and Development Program of China(Grant No.2020YFB1600501)。
文摘With the increasing maturity of automatic driving technology,the homogeneous traffic flow will gradually evolve into the heterogeneous traffic flow,which consists of human-driving and autonomous vehicles.To better study the characteristics of the heterogeneous traffic system,this paper proposes a new car-following model for autonomous vehicles and heterogeneous traffic flow,which considers the self-stabilizing effect of vehicles.Through linear and nonlinear methods,this paper deduces and analyzes the stability of such a car-following model with the self-stabilizing effect.Finally,the model is verified by numerical simulation.Numerical results show that the self-stabilizing effect can make the heterogeneous traffic flow more stable,and that increasing the self-stabilizing coefficient or historical time length can strengthen the stability of heterogeneous traffic flow and alleviate traffic congestion effectively.In addition,the heterogeneous traffic flow can also be stabilized with a higher proportion of autonomous vehicles.
文摘This study investigates the stability problem of gob-side entry retaining （GER） and backfilling wall which located under the key block B. Based on the combined research of elastic-plastic mechanics, structure mechanics and modern theory of mining-induced pressure, the caving characteristic and roof structure over the GER were analyzed, and the vertical force and the torque on retained entry roof were also derived as the position for the retained entry varies. On the basis of the specific geology in Huainan mining area, the results indicate that a relatively more stable position for retained entry neighbors the hinge point of block A and B, and it also located at a scope ranging from this point to the one-third length of block B in horizontal direction. As to appropriate position for backfilling wall, this study recommends partial- road-in backfilling method for GER. Field trial conducted at panel face 12418 of Xieqiao Mine demonstrates that the recommended width for original entry is 3.6 m and the preferred width proportion between original retained entry and original entry is 75 % or so whereas the avoidable one is 88 % or so. These findings provide qualitative references to the mines which share similar geology as what Huainan mining area characterized.
