Fissured clays exhibit unique geotechnical behaviors,with the stiffness characteristics evolving dynamically in response to environmental changes.To address this issue,reported here is a systematic assessment of how d...Fissured clays exhibit unique geotechnical behaviors,with the stiffness characteristics evolving dynamically in response to environmental changes.To address this issue,reported here is a systematic assessment of how dryingewetting(DW)cycles affect the small-strain stiffness characteristics of fissured clay.Resonant column tests are taken to examine the nonlinear attenuation behavior of the small-strain shear modulus(SSSM)and damping ratio of fissured clay under various DW cycle and consolidation pressure(25e200 kPa)conditions.Scanning electron microscopy(SEM)and computed tomography(CT)are employed to reveal the microstructure of fissured clay.The HardineDrnevich(H-D)model is used to describe the decay law of its SSSM,and the small strain stiffness characteristics of fissured soil are analyzed in view of damage mechanics.The results show that the SSSM of the fissured clay decreases as the DWcycles increase,with the greatest attenuation at original soil state.The damping ratio exhibits an incremental trend with escalating strain and a higher number of DW cycles.Regarding damage,DW cycles can lead to the formation of microcracks in the sample,and the aggregates disperse into smaller aggregates,which then aggregates again,resulting in structural damage.The damage variables of the samples under various confining pressures and DW cycles are analyzed based on the principle of strain damage.Finally,the volume changes and the distribution of different pore sizes obtained through CT are analyzed to investigate the stiffness attenuation under DW cycles.Additionally,the study examines the propagation direction of secondary cracks induced by primary fissures,which will play an important role in reduction of the stiffness.Our investigations contribute to understanding of soil mechanics and practical applications in areas where fissured clay is prevalent.展开更多
Due to the invisibility and complexity of the underground spaces,monitoring the propagation and filling characteristics of the grouting slurry post the water–sand mixture inrush in metal mines is challenging,which co...Due to the invisibility and complexity of the underground spaces,monitoring the propagation and filling characteristics of the grouting slurry post the water–sand mixture inrush in metal mines is challenging,which complicates engineering treatment.This research investigated the propagation law of cement-sodium silicate slurry under flowing water conditions within the caving mass of a metal mine.First,based on borehole packer test results and borehole TV images,the fractured strata before grouting were classified into four types:cavity,hidden,fissure,and complete.Second,an orthogonal experimental design was employed to evaluate the impact of four key factors—stratigraphic fragmentation,water flow rate,grouting flow rate,and water-cement ratio—on the efficacy of grouting within a caving mass at the site.The results indicate that the factors influencing grouting efficacy are ranked in the following order of importance:stratigraphic fragmentation>water flow rate>water–cement ratio>grouting flow rate.Ultimately,five propagation filling modes—pure slurry,big crack,small crack,small karst pore,and pore penetration—were identified by examining the propagation filling characteristics of slurry in rock samples,incorporating microscopic material structure analysis through scanning electron microscopy and energy spectrum analysis.The findings of this study provide valuable insights into selecting engineering treatment parameters and methodologies,serving as a reference for preventing and controlling water–sand mixture inrush in metal mines,thereby enhancing treatment efficacy and ensuring grouting success.展开更多
Ground fissure,as a common geo-hazard,impairs the integrity of the site soil and affects the seismic performance of engineering structures.In this paper,a finite element(FE)model for subway stations in a ground fissur...Ground fissure,as a common geo-hazard,impairs the integrity of the site soil and affects the seismic performance of engineering structures.In this paper,a finite element(FE)model for subway stations in a ground fissure area was developed and validated by using experimental results.Numerical analyses were conducted to investigate the seismic response and failure mode of subway stations in a ground fissure area with different locations.Effects of ground fissure on deformations and internal forces of a station,soil pressures and soil plastic strains were discussed.The results showed that the seismic response of the station was significantly amplified by the ground fissure,and stations in the ground fissure area displayed obvious rocking deformation during earthquakes as compared to those in the area without fissures.It also was found that the soil yielding around the station,the dislocation occurring in the ground fissure area,and the dynamic amplification effect were more significant under vertical ground motion,which weakened the station’s ductility and accelerated its destruction process.展开更多
Since the 1950's,212 earth fissures have been discovered in the Wei River Basin.During a field survey in 2016,an additional 48 earth fissures were discovered in Anren area,northeast of the Wei River Basin.The char...Since the 1950's,212 earth fissures have been discovered in the Wei River Basin.During a field survey in 2016,an additional 48 earth fissures were discovered in Anren area,northeast of the Wei River Basin.The characteristics and formation mechanisms of these fissures were studied through field investigations,measurements,trench excavation,and drilling.On-site investigations indicated that these earth fissures were distributed along a fault-controlled geomorphic boundary.Fissures trended at 60°-80°NE and were divided into five groups.Trenches revealed multiple secondary fissures,exposing severe soil ruptures in the shallow earth surfaces.Drilling profiles revealed that earth fissures dislocated several strata,and resembled synsedimentary faults.Seismic reflection profiles revealed buried faults beneath the earth fissures.The Anren area fissures formed in the following three stages:regional extension that initially generated multiple buried faults;seismic activity rupturing multiple strata,resulting in multiple buried fractures;and finally,erosion processes that propagated the buried fractures to the surface,forming the current earth fissures.展开更多
Granite saprolite(GS)slope failure is a common yet catastrophic phenomenon in South China.Although the impact of subtropical climate,characterized by high temperatures and heavy rainfall,is widely recognized,the effec...Granite saprolite(GS)slope failure is a common yet catastrophic phenomenon in South China.Although the impact of subtropical climate,characterized by high temperatures and heavy rainfall,is widely recognized,the effect of the capillary imbibition and drying(CID)process,which frequently occurs during the dry season,on the hydro-mechanical properties of GS and slope stability is largely overlooked.This research examines natural GS specimens with various degrees of weathering subjected to CID cycles.The study investigates the capillary imbibition(CI)process and the evolution of the soil's hydromechanical properties across CID cycles.The results indicate that the CI process in GS is fundamentally different from that in clays and sands.The aggregated structure of GS comprising numerous fissures and large pores plays a critical role.In addition,the CID cycles cause the hydro-mechanical degradation of GS,including a finer particle composition,decreased shear strength,and increased permeability and disintegration potential,where damage to soil cementation and fissure development are identified as critical factors.This investigation reveals new insights into the mechanical properties of GS that are essential for the development of effective landslide management strategies in South China.展开更多
The recent upsurge in metro construction emphasizes the necessity of understanding the mechanical performance of metro shield tunnel subjected to the influence of ground fissures.In this study,a largescale experiment,...The recent upsurge in metro construction emphasizes the necessity of understanding the mechanical performance of metro shield tunnel subjected to the influence of ground fissures.In this study,a largescale experiment,in combination with numerical simulation,was conducted to investigate the influence of ground fissures on a metro shield tunnel.The results indicate that the lining contact pressure at the vault increases in the hanging wall while decreases in the footwall,resulting in a two-dimensional stress state of vertical shear and axial tension-compression,and simultaneous vertical dislocation and axial tilt for the segments around the ground fissure.In addition,the damage to curved bolts includes tensile yield,flexural yield,and shear twist,leading to obvious concrete lining damage,particularly at the vault,arch bottom,and hance,indicating that the joints in these positions are weak areas.The shield tunnel orthogonal to the ground fissure ultimately experiences shear failure,suggesting that the maximum actual dislocation of ground fissure that the structure can withstand is approximately 20 cm,and five segment rings in the hanging wall and six segment rings in the footwall also need to be reinforced.This study could provide a reference for metro design in ground fissure sites.展开更多
Fissured coal mass under triaxial unloading condition exhibits higher burst potential than the triaxial loading condition,which poses challenge to safety and productivity of resources extraction and underground space ...Fissured coal mass under triaxial unloading condition exhibits higher burst potential than the triaxial loading condition,which poses challenge to safety and productivity of resources extraction and underground space utilization.To comprehensively understand the mechanism of unloading-induced burst during excavation process,this study investigated the fracture and energy evolution of samples with different fissure types such as single,two parallel,and two coplanar-parallel using PFC2D modelling.Triaxial loading tests were conducted to determine the compressive strengths and other parameters.With increase of fissure inclination angle,the triaxial compressive strength decreases forβ=0°-30°,and then increase forβ=30°-90°.The strength of samples with two coplanar-parallel fissures is the highest.Fissure can significantly change the distribution of fracture and elastic energy.Secondary cracks were generated starting from both ends of the fissure.Forβ=0°-60°,low elastic strain energy area was produced around the fissure along the loading direction.The elastic strain energy is transferred to the outside of fissures.Forβ=75°-90°,only a small amount of high elastic strain energy was generated on both sides of the fissure.The fracture expansion under unloading conditions occurred due to tensile stress T caused by unloading differential rebound deformation and the shear stress on the fissure surface.展开更多
This article comments on the study by Peng et al,published in the World Journal of Gastrointestinal Surgery,representing a notable advancement in hepatobiliary surgery.This article examines laparoscopic anatomical seg...This article comments on the study by Peng et al,published in the World Journal of Gastrointestinal Surgery,representing a notable advancement in hepatobiliary surgery.This article examines laparoscopic anatomical segment VIII resection,a challenging procedure due to the complex liver anatomy and difficulty in accessing deep-seated lesions.Peng and colleagues’experience with caudal and cranial approaches in 34 patients underscores the feasibility of these techniques while sparking debates about the optimal approach.Their study’s strengths lie in technique standardization and comprehensive analysis,although its limitations highlight the need for further research.As minimally invasive liver surgery progresses,larger,prospective trials and integration of advanced technologies are essential for establishing best practices.展开更多
Taking the Pusa Collapse in Nayong County,Guizhou Province,China as a case study,this paper investigates the impact of multi-layer coal mining on karst mountains characterized by deep fissures.Based on field investiga...Taking the Pusa Collapse in Nayong County,Guizhou Province,China as a case study,this paper investigates the impact of multi-layer coal mining on karst mountains characterized by deep fissures.Based on field investigations and employing discrete element numerical simulations,the deformation and failure mechanisms of karst mountain containing deep and large fissures under multi-seam mining conditions was investigated.The influence of the direction of coal seam extraction and the sequence of extraction between multiple coal seams on the failure modes of karst mountain with deep and large fissures was studied.The results indicate that underground mining primarily manifests in the development of mininginduced fissures in the mountain body,subsidence and deformation of slope masses,and triggering the expansion of existing fissures,further driving overall deformation and damage to the slopes.Deep and large fissures control the deformation and failure modes of the slopes,with closer and longer deep and large fissures near the slope surface exerting greater influence on the slope mass.The impact of mining in the same coal seam direction on the slopes is mainly reflected in the process of slope deformation and failure.Downslope mining directly leads to overall subsidence of the slope mass,squeezing the front and lower parts of the slope mass.Upslope mining initially causes the foot of the slope to sink and the entire slope mass to move outward,and continuous mining leads to overall settlement and downward compression deformation of the slope.The sequence of mining between multiple coal seams mainly affects the overall and local deformation values of the slope mass.Downward mining leads to increased overall subsidence of the slope mass and exacerbates the backward tilt of the slope top.展开更多
Granite residual soil slope is often destroyed,which poses great threats to Rong County in southeastern Guangxi,China.Heavy rainfall and fissures are the major triggering and internal factors.The fissure that controls...Granite residual soil slope is often destroyed,which poses great threats to Rong County in southeastern Guangxi,China.Heavy rainfall and fissures are the major triggering and internal factors.The fissure that controls the slope stability and the associated failure mechanisms remain unclear.The purpose of this study was to identify the controlling fissures through field investigation,elucidate the effect of its position,and analyze the failure process and hydrological response of residual soil slope through artificial flume model tests.The results comprised five aspects.(1)Surface weathering and unloading fissures could affect slope stability.(2)The failure processes with different fissure positions exhibited inconsistent characteristics.(3)The volume moisture content(VMC)had the most direct response at the fissure tip.The corresponding infiltration rate was the highest.The response time of pore water pressure(PWP)was longer than that of VMC.Fluctuations in PWP were associated with VMC and changes in the soil microstructure due to local deformation.(4)Slope failure was accompanied by serious soil erosion.This could be attributed to the infiltration direction and the interaction between soil and water.(5)Fissured soil slopes experienced five similar failure processes:sheet erosion and partial failure of the slope foot,occurrence of preferential flow and enlargement of the sliding area,creep deformation and tension fissure emergence,block sliding and gully erosion,and flow-slip.展开更多
Karst phenomena occurring on land surface create sinkholes,ground fissures and other hazardous events.Dissolution of gypsum of Upper Devonian formations in North Lithuania,that occur under thin Quaternary cover result...Karst phenomena occurring on land surface create sinkholes,ground fissures and other hazardous events.Dissolution of gypsum of Upper Devonian formations in North Lithuania,that occur under thin Quaternary cover results with rapid occurrence of hazardous sinkholes.Monitoring of karst phenomena in Lithuania includes measurements of volumes of karst sinkholes(cubic meters)and amount of dissolved underground gypsum–named chemical gypsum denudation measured by amount cubic meters of gypsum dissolved from 1 square kilometer of karst terrain during one year.展开更多
Dear Editor,Brown syndrome is an ocular motility disorder characterized by restriction of elevation in adduction combined with a positive forced duction test and minimal or no superior oblique(SO)overaction[1].Other f...Dear Editor,Brown syndrome is an ocular motility disorder characterized by restriction of elevation in adduction combined with a positive forced duction test and minimal or no superior oblique(SO)overaction[1].Other features include V-pattern horizontal deviation and palpebral fissure widening while adduction[1].展开更多
This study investigated the impacts of random negative training datasets(NTDs)on the uncertainty of machine learning models for geologic hazard susceptibility assessment of the Loess Plateau,northern Shaanxi Province,...This study investigated the impacts of random negative training datasets(NTDs)on the uncertainty of machine learning models for geologic hazard susceptibility assessment of the Loess Plateau,northern Shaanxi Province,China.Based on randomly generated 40 NTDs,the study developed models for the geologic hazard susceptibility assessment using the random forest algorithm and evaluated their performances using the area under the receiver operating characteristic curve(AUC).Specifically,the means and standard deviations of the AUC values from all models were then utilized to assess the overall spatial correlation between the conditioning factors and the susceptibility assessment,as well as the uncertainty introduced by the NTDs.A risk and return methodology was thus employed to quantify and mitigate the uncertainty,with log odds ratios used to characterize the susceptibility assessment levels.The risk and return values were calculated based on the standard deviations and means of the log odds ratios of various locations.After the mean log odds ratios were converted into probability values,the final susceptibility map was plotted,which accounts for the uncertainty induced by random NTDs.The results indicate that the AUC values of the models ranged from 0.810 to 0.963,with an average of 0.852 and a standard deviation of 0.035,indicating encouraging prediction effects and certain uncertainty.The risk and return analysis reveals that low-risk and high-return areas suggest lower standard deviations and higher means across multiple model-derived assessments.Overall,this study introduces a new framework for quantifying the uncertainty of multiple training and evaluation models,aimed at improving their robustness and reliability.Additionally,by identifying low-risk and high-return areas,resource allocation for geologic hazard prevention and control can be optimized,thus ensuring that limited resources are directed toward the most effective prevention and control measures.展开更多
To explore the effects of freeze‒thaw cycles on the mechanical properties and crack evolution of fissured sandstone,biaxial compression experiments were carried out on sandstone subjected to freeze‒thaw cycles to char...To explore the effects of freeze‒thaw cycles on the mechanical properties and crack evolution of fissured sandstone,biaxial compression experiments were carried out on sandstone subjected to freeze‒thaw cycles to characterize the changes in the physical and mechanical properties of fissured sandstone caused by freeze‒thaw cycles.The crack evolution and crack change process on the surface of the fissured sandstone were recorded and analysed in detail via digital image technology(DIC).Numerical simulation was used to reveal the expansion process and damage mode of fine-scale cracks under the action of freeze‒thaw cycles,and the simulation results were compared and analysed with the experimental data to verify the reliability of the numerical model.The results show that the mass loss,porosity,peak stress and elastic modulus all increase with increasing number of freeze‒thaw cycles.With an increase in the number of freeze‒thaw cycles,a substantial change in displacement occurs around the prefabricated cracks,and a stress concentration appears at the crack tip.As new cracks continue to sprout at the tips of the prefabricated cracks until the microcracks gradually penetrate into the main cracks,the displacement cloud becomes obviously discontinuous,and the contours of the displacement field in the crack fracture damage area simply intersect with the prefabricated cracks to form an obvious fracture.The damage patterns of the fractured sandstone after freeze‒thaw cycles clearly differ,forming a symmetrical"L"-shaped damage pattern at zero freeze‒thaw cycles,a symmetrical"V"-shaped damage pattern at 10 freeze‒thaw cycles,and a"V"-shaped damage pattern at 20 freeze‒thaw cycles.After 20 freeze‒thaw cycles,a"V"-shaped destruction pattern and"L"-shaped destruction pattern are formed;after 30 freeze‒thaw cycles,an"N"-shaped destruction pattern is formed.This shows that the failure mode of fractured sandstone gradually becomes more complicated with an increasing number of freeze‒thaw cycles.The effects of freeze‒thaw cycles on the direction and rate of crack propagation are revealed through a temperature‒load coupled model,which provides an important reference for an in-depth understanding of the freeze‒thaw failure mechanisms of fractured rock masses.展开更多
The damage evolution process of non-penetrating cracks often causes some unexpected engineering disasters.Gypsum specimens containing non-penetrating crack(s)are used to study the damage evolution and characteristics ...The damage evolution process of non-penetrating cracks often causes some unexpected engineering disasters.Gypsum specimens containing non-penetrating crack(s)are used to study the damage evolution and characteristics under cyclic loading.The results show that under cyclic loading,the relationship between the number of non-penetrating crack(s)and the characteristic parameters(cyclic number,peak stress,peak strain,failure stress,and failure strain)of the pre-cracked specimens can be represented by a decreasing linear function.The damage evolution equation is fitted by calibrating the accumulative plastic strain for each cycle,and the damage constitutive equation is proposed by the concept of effective stress.Additionally,non-penetrating cracks are more likely to cause uneven stress distribution,damage accumulation,and local failure of specimen.The local failure can change the stress distribution and relieve the inhibition of non-penetrating crack extension and eventually cause a dramatic destruction of the specimen.Therefore,the evolution process caused by non-penetrating cracks can be regarded as one of the important reasons for inducing rockburst.These results are expected to improve the understanding of the process of spalling formation and rockburst and can be used to analyze the stability of rocks or rock structures.展开更多
BACKGROUND Laparoscopic hepatectomy is a proven safe and technically feasible approach for liver tumor resection,but laparoscopic anatomical SVIII resection(LASVIIIR)remains rarely reported due to poor accessibility,d...BACKGROUND Laparoscopic hepatectomy is a proven safe and technically feasible approach for liver tumor resection,but laparoscopic anatomical SVIII resection(LASVIIIR)remains rarely reported due to poor accessibility,difficult exposure,and the deep-lying Glissonean pedicle.This study examined the safety,feasibility,and perio-perative outcomes of LASVIIIR via a middle hepatic fissure approach at our in-stitution.AIM To investigate the safety,feasibility,and perioperative outcomes of LASVIIIR via a middle hepatic fissure approach at our institution.METHODS From November 2017 to December 2022,all patients with a liver tumor who underwent LASVIIIR were enrolled.The perioperative outcomes and postope-rative complications were evaluated.RESULTS Thirty-four patients underwent LASVIIIR via a middle hepatic fissure approach from the side or cranio side and were included.The mean operation time was 164±54 minutes,and the intra-operative blood loss was 100 mL(range:20-1000 mL).The mean operative times were,respectively,152±50 minutes and 222±29 minutes(P=0.001)for the caudal side and cranial side approaches.In addition,the median blood loss volumes were 100 mL(range:20-300 mL)and 250 mL(range:20-1000 mL),respectively,for the caudal and cranial sides(P=0.064).Three patients treated using the cranial side approach experienced bile leakage,while 1 patient treated using the caudal side approach had subphrenic collection and underwent percutaneous drainage to successfully recover.There were no differences regarding postoperative hospital stays for the caudal and cranial side approaches[9(7-26)days vs 8(8-19)days](P=0.226).CONCLUSION LASVIIIR resection remains a challenging operation,but the middle hepatic fissure approach is a reasonable and easy-to-implement technique.展开更多
In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads.In this paper,the dynamic behaviors and fracture characteristics of red sandston...In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads.In this paper,the dynamic behaviors and fracture characteristics of red sandstone considering temperatures(25℃,200℃,400℃,600℃,and 800℃)and fissure angles(0°,30°,60°,and 90°)were evaluated under constant-amplitude and low-cycle(CALC)impacts actuated by a modified split Hopkinson pressure bar(SHPB)system.Subsequently,fracture morphology and second-order statistics within the grey-level co-occurrence matrix(GLCM)were examined using scanning electron microscopy(SEM).Meanwhile,the deep analysis and discussion of the mechanical response were conducted through the synchronous thermal analyzer(STA)test,numerical simulations,one-dimensional stress wave theory,and material structure.The multiple regression models between response variables and interactive effects of independent variables were established using the response surface method(RSM).The results demonstrate the fatigue strength and life diminish as temperatures rise and increase with increasing fissure angles,while the strain rate exhibits an inverse behavior.Furthermore,the peak stress intensification and strain rate softening observed during CALC impact exhibit greater prominence at increased fissure angles.The failure is dominated by tensile damage with concise evolution paths and intergranular cracks as well as the compressor-crushed zone which may affect the failure mode after 400℃.The second-order statistics of GLCM in SEM images exhibit a considerable dependence on the temperatures.Also,thermal damage dominated by thermal properties controls the material structure and wave impedance and eventually affects the incident wave intensity.The tensile wave reflected from the fissure surface is the inherent mechanism responsible for the angle effect exhibited by the fatigue strength and life.Ultimately,the peak stress intensification and strain rate softening during impact are determined by both the material structure and compaction governed by thermal damage and tensile wave.展开更多
Anal pruritus is a common anorectal symptom that can significantly impair a patient’s quality of life,including their mental health.It can be one of the most difficult proctological conditions to treat.Patients often...Anal pruritus is a common anorectal symptom that can significantly impair a patient’s quality of life,including their mental health.It can be one of the most difficult proctological conditions to treat.Patients often delay seeking medical attention,since it is an embarrassing but non-life-threatening situation.Pruritus ani can be associated with idiopathic and secondary causes,such as anorectal diseases,cancer(anal or colorectal),dermatological and sexually transmitted diseases,fungal infections and systemic diseases.If patients are referred for a colonoscopy,this can sometimes provide the first opportunity to evaluate the perianal area.Classifications of anal pruritus are based on the abnormalities of the perianal skin,one of the most commonly used being the Washington classi-fication.A proper digital anorectal examination is important,as well as an anoscopy to help to exclude anorectal diseases or suspicious masses.Endoscopists should be aware of the common etiologies,and classification of the perianal area abnormalities should be provided in the colonoscopy report.Information on treatment possibilities and follow-up can also be provided.The treatment normally consists of a triple approach:proper hygiene,elimination of irritants,and skin care and protection.Several topical therapies have been described as possible treatments,including steroids,capsaicin,tacrolimus and methylene blue intradermal injections.展开更多
Nearly 1100 fissures have formed on the Hebei Plain in China.Within the Yellow RiverQinghe River-Zhanghe River shallow buried paleochannel band on the plain,93 ground fissures controlled by paleochannels have develope...Nearly 1100 fissures have formed on the Hebei Plain in China.Within the Yellow RiverQinghe River-Zhanghe River shallow buried paleochannel band on the plain,93 ground fissures controlled by paleochannels have developed,of which the Wuyi-Fuping ground fissure is a typical paleochannel-controlled fissure located in Hengshui,Hebei Province,with a total length of 3 km,a dominant strike of NE78°,and nearly upright in the shallow layer.The surface damage observed in this fissure primarily manifests as beaded pits,and its activity shows distinct segmentation characteristics.On the trench profiles,the offset distance of shallow layers remains consistently around 20 cm within the depth range of 0 to-3 m.An evident flexure is observed in the strata at depths ranging from-4.5 to-7 m.The drilling profile reveals that there is an absence of dislocations in the deeper strata.Nonetheless,the shallow seismic physical profiles unveil the presence of underlying faults beneath the study area,underscoring the intricate formation process and genesis mechanism of the Wuyi-Fuping ground fissure.Firstly,the formation and evolution of the Qingling River's paleochannel were shaped by the actions of fault blocks and underlying faults.The interplay of the regional stress field,fault block movement,and fault activity played pivotal roles in driving the development of this paleochannel.Secondly,the paleochannel exerts a controlling influence on the development location and severity of the fissure.During pumping,the confined aquifer within the paleochannel undergoes water loss and compression,resulting in the formation of a surface subsidence funnel.When the tensile stress surpasses the soil's tensile strength at the funnel's edge,the soil fractures give rise to a ground fissure.Finally,large amounts of surface water generated by heavy rainfall and irrigation can cause existing hidden ground fissures to rupture,emerge,and expand.This paper provides a heretofore generally unknown example,promotes research on the mechanisms of paleochannel-controlled fissures,and has guiding significance for disaster prevention and reduction in this area.展开更多
The Inner Mongolia mining area in western China are characterized by the development of numerous penetrating fissures,resulting in severe land damage.It is significant to reveal the underlying evolution mechanism and ...The Inner Mongolia mining area in western China are characterized by the development of numerous penetrating fissures,resulting in severe land damage.It is significant to reveal the underlying evolution mechanism and identify treatment timing for restoring the ecological environment.The Guanbanwusu mining subsidence area in Inner Mongolia,China was selected as the research case for this study.The evolution mechanism of different penetrating fissures was revealed by field measurement,physical simulation and theoretical analysis.The treatment timing prediction model for the mining subsidence area was established based on the enhanced Weibull time function.The results show that the ground fissures are mainly step-type and collapse-type fissures.The breaking form of overlying strata determines their vertical opening and horizontal dislocation.The high mining intensity in the western mining area results in a shortened period of dynamic fissure expansion and reduced closure degree.The damage extent of the overlying strata exhibits zoning characteristics both vertically and horizontally.The relative standard deviation of the prediction model is only 3.7%.Concurrently,the prediction model is employed to determine the optimal timing for treatment in the study area,estimated to be 259 days.Subsequently,once this threshold is reached,the study area undergoes treatment and restoration of its e cological environment.This study addresses the knowledge gap in this field by highlighting the interconnectedness between rock strata structure and evolution mechanism of penetrating fissures,thereby providing a method for determining the treatment timing in mining subsidence areas.展开更多
基金the financial support of the National Key Research and Development Program of China(Grant No.2019YFC1509901).
文摘Fissured clays exhibit unique geotechnical behaviors,with the stiffness characteristics evolving dynamically in response to environmental changes.To address this issue,reported here is a systematic assessment of how dryingewetting(DW)cycles affect the small-strain stiffness characteristics of fissured clay.Resonant column tests are taken to examine the nonlinear attenuation behavior of the small-strain shear modulus(SSSM)and damping ratio of fissured clay under various DW cycle and consolidation pressure(25e200 kPa)conditions.Scanning electron microscopy(SEM)and computed tomography(CT)are employed to reveal the microstructure of fissured clay.The HardineDrnevich(H-D)model is used to describe the decay law of its SSSM,and the small strain stiffness characteristics of fissured soil are analyzed in view of damage mechanics.The results show that the SSSM of the fissured clay decreases as the DWcycles increase,with the greatest attenuation at original soil state.The damping ratio exhibits an incremental trend with escalating strain and a higher number of DW cycles.Regarding damage,DW cycles can lead to the formation of microcracks in the sample,and the aggregates disperse into smaller aggregates,which then aggregates again,resulting in structural damage.The damage variables of the samples under various confining pressures and DW cycles are analyzed based on the principle of strain damage.Finally,the volume changes and the distribution of different pore sizes obtained through CT are analyzed to investigate the stiffness attenuation under DW cycles.Additionally,the study examines the propagation direction of secondary cracks induced by primary fissures,which will play an important role in reduction of the stiffness.Our investigations contribute to understanding of soil mechanics and practical applications in areas where fissured clay is prevalent.
基金The National Natural Science Foundation of China,Grant/Award Number:42130706。
文摘Due to the invisibility and complexity of the underground spaces,monitoring the propagation and filling characteristics of the grouting slurry post the water–sand mixture inrush in metal mines is challenging,which complicates engineering treatment.This research investigated the propagation law of cement-sodium silicate slurry under flowing water conditions within the caving mass of a metal mine.First,based on borehole packer test results and borehole TV images,the fractured strata before grouting were classified into four types:cavity,hidden,fissure,and complete.Second,an orthogonal experimental design was employed to evaluate the impact of four key factors—stratigraphic fragmentation,water flow rate,grouting flow rate,and water-cement ratio—on the efficacy of grouting within a caving mass at the site.The results indicate that the factors influencing grouting efficacy are ranked in the following order of importance:stratigraphic fragmentation>water flow rate>water–cement ratio>grouting flow rate.Ultimately,five propagation filling modes—pure slurry,big crack,small crack,small karst pore,and pore penetration—were identified by examining the propagation filling characteristics of slurry in rock samples,incorporating microscopic material structure analysis through scanning electron microscopy and energy spectrum analysis.The findings of this study provide valuable insights into selecting engineering treatment parameters and methodologies,serving as a reference for preventing and controlling water–sand mixture inrush in metal mines,thereby enhancing treatment efficacy and ensuring grouting success.
基金National Natural Science Foundation of China under Grant No.52108473Project of Shaanxi Engineering Technology Research Center for Urban Geology and Underground Space under Grant No.2025KT-03Key Project of Education Department of Shaanxi Province under Grant No.23JY042。
文摘Ground fissure,as a common geo-hazard,impairs the integrity of the site soil and affects the seismic performance of engineering structures.In this paper,a finite element(FE)model for subway stations in a ground fissure area was developed and validated by using experimental results.Numerical analyses were conducted to investigate the seismic response and failure mode of subway stations in a ground fissure area with different locations.Effects of ground fissure on deformations and internal forces of a station,soil pressures and soil plastic strains were discussed.The results showed that the seismic response of the station was significantly amplified by the ground fissure,and stations in the ground fissure area displayed obvious rocking deformation during earthquakes as compared to those in the area without fissures.It also was found that the soil yielding around the station,the dislocation occurring in the ground fissure area,and the dynamic amplification effect were more significant under vertical ground motion,which weakened the station’s ductility and accelerated its destruction process.
基金the CMEC Technology Incubation Project(No.CMEC-KJFH-2018-02)the National Science Foundation of China(No.41877250)+2 种基金the Fundamental Research Funds for the Central Universities,CHD(Nos.300102263512 and 300102260401)Shaanxi Science and Technology Coordination Innovation Project(No.2011KTZB03-02-02)the National Geological Survey of China(No.DD20160264)。
文摘Since the 1950's,212 earth fissures have been discovered in the Wei River Basin.During a field survey in 2016,an additional 48 earth fissures were discovered in Anren area,northeast of the Wei River Basin.The characteristics and formation mechanisms of these fissures were studied through field investigations,measurements,trench excavation,and drilling.On-site investigations indicated that these earth fissures were distributed along a fault-controlled geomorphic boundary.Fissures trended at 60°-80°NE and were divided into five groups.Trenches revealed multiple secondary fissures,exposing severe soil ruptures in the shallow earth surfaces.Drilling profiles revealed that earth fissures dislocated several strata,and resembled synsedimentary faults.Seismic reflection profiles revealed buried faults beneath the earth fissures.The Anren area fissures formed in the following three stages:regional extension that initially generated multiple buried faults;seismic activity rupturing multiple strata,resulting in multiple buried fractures;and finally,erosion processes that propagated the buried fractures to the surface,forming the current earth fissures.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.42307212 and 42177148)the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(Grant No.SKLGME023005).
文摘Granite saprolite(GS)slope failure is a common yet catastrophic phenomenon in South China.Although the impact of subtropical climate,characterized by high temperatures and heavy rainfall,is widely recognized,the effect of the capillary imbibition and drying(CID)process,which frequently occurs during the dry season,on the hydro-mechanical properties of GS and slope stability is largely overlooked.This research examines natural GS specimens with various degrees of weathering subjected to CID cycles.The study investigates the capillary imbibition(CI)process and the evolution of the soil's hydromechanical properties across CID cycles.The results indicate that the CI process in GS is fundamentally different from that in clays and sands.The aggregated structure of GS comprising numerous fissures and large pores plays a critical role.In addition,the CID cycles cause the hydro-mechanical degradation of GS,including a finer particle composition,decreased shear strength,and increased permeability and disintegration potential,where damage to soil cementation and fissure development are identified as critical factors.This investigation reveals new insights into the mechanical properties of GS that are essential for the development of effective landslide management strategies in South China.
基金supported by the National Key Research&Development Program of China(Grant No.2023YFC3008404)the Key Laboratory of Earth Fissures Geological Disaster,Ministry of Natural Resources,China(Grant Nos.EFGD20240609 and EFGD20240610).
文摘The recent upsurge in metro construction emphasizes the necessity of understanding the mechanical performance of metro shield tunnel subjected to the influence of ground fissures.In this study,a largescale experiment,in combination with numerical simulation,was conducted to investigate the influence of ground fissures on a metro shield tunnel.The results indicate that the lining contact pressure at the vault increases in the hanging wall while decreases in the footwall,resulting in a two-dimensional stress state of vertical shear and axial tension-compression,and simultaneous vertical dislocation and axial tilt for the segments around the ground fissure.In addition,the damage to curved bolts includes tensile yield,flexural yield,and shear twist,leading to obvious concrete lining damage,particularly at the vault,arch bottom,and hance,indicating that the joints in these positions are weak areas.The shield tunnel orthogonal to the ground fissure ultimately experiences shear failure,suggesting that the maximum actual dislocation of ground fissure that the structure can withstand is approximately 20 cm,and five segment rings in the hanging wall and six segment rings in the footwall also need to be reinforced.This study could provide a reference for metro design in ground fissure sites.
基金supported by the National Science and Technology Major Project(2024ZD1000705)the Basic Research Project of Liaoning Provincial Department of Education-Key Project of Independent Topic Selection(LJ212410147007).
文摘Fissured coal mass under triaxial unloading condition exhibits higher burst potential than the triaxial loading condition,which poses challenge to safety and productivity of resources extraction and underground space utilization.To comprehensively understand the mechanism of unloading-induced burst during excavation process,this study investigated the fracture and energy evolution of samples with different fissure types such as single,two parallel,and two coplanar-parallel using PFC2D modelling.Triaxial loading tests were conducted to determine the compressive strengths and other parameters.With increase of fissure inclination angle,the triaxial compressive strength decreases forβ=0°-30°,and then increase forβ=30°-90°.The strength of samples with two coplanar-parallel fissures is the highest.Fissure can significantly change the distribution of fracture and elastic energy.Secondary cracks were generated starting from both ends of the fissure.Forβ=0°-60°,low elastic strain energy area was produced around the fissure along the loading direction.The elastic strain energy is transferred to the outside of fissures.Forβ=75°-90°,only a small amount of high elastic strain energy was generated on both sides of the fissure.The fracture expansion under unloading conditions occurred due to tensile stress T caused by unloading differential rebound deformation and the shear stress on the fissure surface.
基金Supported by National Natural Science Foundation of China,No.82170406 and No.81970238.
文摘This article comments on the study by Peng et al,published in the World Journal of Gastrointestinal Surgery,representing a notable advancement in hepatobiliary surgery.This article examines laparoscopic anatomical segment VIII resection,a challenging procedure due to the complex liver anatomy and difficulty in accessing deep-seated lesions.Peng and colleagues’experience with caudal and cranial approaches in 34 patients underscores the feasibility of these techniques while sparking debates about the optimal approach.Their study’s strengths lie in technique standardization and comprehensive analysis,although its limitations highlight the need for further research.As minimally invasive liver surgery progresses,larger,prospective trials and integration of advanced technologies are essential for establishing best practices.
基金supported by the National Key R&D Program of China(Grant No.2018YFC1504802)the National Natural Science Foundation of China(Grant No.52074042)。
文摘Taking the Pusa Collapse in Nayong County,Guizhou Province,China as a case study,this paper investigates the impact of multi-layer coal mining on karst mountains characterized by deep fissures.Based on field investigations and employing discrete element numerical simulations,the deformation and failure mechanisms of karst mountain containing deep and large fissures under multi-seam mining conditions was investigated.The influence of the direction of coal seam extraction and the sequence of extraction between multiple coal seams on the failure modes of karst mountain with deep and large fissures was studied.The results indicate that underground mining primarily manifests in the development of mininginduced fissures in the mountain body,subsidence and deformation of slope masses,and triggering the expansion of existing fissures,further driving overall deformation and damage to the slopes.Deep and large fissures control the deformation and failure modes of the slopes,with closer and longer deep and large fissures near the slope surface exerting greater influence on the slope mass.The impact of mining in the same coal seam direction on the slopes is mainly reflected in the process of slope deformation and failure.Downslope mining directly leads to overall subsidence of the slope mass,squeezing the front and lower parts of the slope mass.Upslope mining initially causes the foot of the slope to sink and the entire slope mass to move outward,and continuous mining leads to overall settlement and downward compression deformation of the slope.The sequence of mining between multiple coal seams mainly affects the overall and local deformation values of the slope mass.Downward mining leads to increased overall subsidence of the slope mass and exacerbates the backward tilt of the slope top.
基金financially supported by the National Natural Science Foundation of China(No.41901132)the Natural Scientific Project of Guangxi Zhuang Autonomous Region(Nos.2019GXNSFAA185015,2021GXNSFBA220025)+1 种基金the Interdisciplinary Scientific Research Foundation of Guangxi University(No.2022JCC026)the Project of Key Laboratory of Early Rapid Identification,Prevention and Control of Geological Diseases in Traffic Corridor of High Intensity Earthquake Mountainous Area of Yunnan Province(No.KLGDTC-2021-01)。
文摘Granite residual soil slope is often destroyed,which poses great threats to Rong County in southeastern Guangxi,China.Heavy rainfall and fissures are the major triggering and internal factors.The fissure that controls the slope stability and the associated failure mechanisms remain unclear.The purpose of this study was to identify the controlling fissures through field investigation,elucidate the effect of its position,and analyze the failure process and hydrological response of residual soil slope through artificial flume model tests.The results comprised five aspects.(1)Surface weathering and unloading fissures could affect slope stability.(2)The failure processes with different fissure positions exhibited inconsistent characteristics.(3)The volume moisture content(VMC)had the most direct response at the fissure tip.The corresponding infiltration rate was the highest.The response time of pore water pressure(PWP)was longer than that of VMC.Fluctuations in PWP were associated with VMC and changes in the soil microstructure due to local deformation.(4)Slope failure was accompanied by serious soil erosion.This could be attributed to the infiltration direction and the interaction between soil and water.(5)Fissured soil slopes experienced five similar failure processes:sheet erosion and partial failure of the slope foot,occurrence of preferential flow and enlargement of the sliding area,creep deformation and tension fissure emergence,block sliding and gully erosion,and flow-slip.
基金supported by the Ministry of Education,Science and Sport of Republic of Lithuania under the program“An influence of the climate of the climatic and anthropogenic driven factors on the ecosystems and their behaviors,services provided and sustainability of the resources”(20220419/V-585)The monitoring of karst denudation and mapping of sinkholes was funded by Lithuanian Geological Survey under Ministry of Environment,Republic of Lithuania.
文摘Karst phenomena occurring on land surface create sinkholes,ground fissures and other hazardous events.Dissolution of gypsum of Upper Devonian formations in North Lithuania,that occur under thin Quaternary cover results with rapid occurrence of hazardous sinkholes.Monitoring of karst phenomena in Lithuania includes measurements of volumes of karst sinkholes(cubic meters)and amount of dissolved underground gypsum–named chemical gypsum denudation measured by amount cubic meters of gypsum dissolved from 1 square kilometer of karst terrain during one year.
文摘Dear Editor,Brown syndrome is an ocular motility disorder characterized by restriction of elevation in adduction combined with a positive forced duction test and minimal or no superior oblique(SO)overaction[1].Other features include V-pattern horizontal deviation and palpebral fissure widening while adduction[1].
基金supported by a project entitled Loess Plateau Region-Watershed-Slope Geological Hazard Multi-Scale Collaborative Intelligent Early Warning System of the National Key R&D Program of China(2022YFC3003404)a project of the Shaanxi Youth Science and Technology Star(2021KJXX-87)public welfare geological survey projects of Shaanxi Institute of Geologic Survey(20180301,201918,202103,and 202413).
文摘This study investigated the impacts of random negative training datasets(NTDs)on the uncertainty of machine learning models for geologic hazard susceptibility assessment of the Loess Plateau,northern Shaanxi Province,China.Based on randomly generated 40 NTDs,the study developed models for the geologic hazard susceptibility assessment using the random forest algorithm and evaluated their performances using the area under the receiver operating characteristic curve(AUC).Specifically,the means and standard deviations of the AUC values from all models were then utilized to assess the overall spatial correlation between the conditioning factors and the susceptibility assessment,as well as the uncertainty introduced by the NTDs.A risk and return methodology was thus employed to quantify and mitigate the uncertainty,with log odds ratios used to characterize the susceptibility assessment levels.The risk and return values were calculated based on the standard deviations and means of the log odds ratios of various locations.After the mean log odds ratios were converted into probability values,the final susceptibility map was plotted,which accounts for the uncertainty induced by random NTDs.The results indicate that the AUC values of the models ranged from 0.810 to 0.963,with an average of 0.852 and a standard deviation of 0.035,indicating encouraging prediction effects and certain uncertainty.The risk and return analysis reveals that low-risk and high-return areas suggest lower standard deviations and higher means across multiple model-derived assessments.Overall,this study introduces a new framework for quantifying the uncertainty of multiple training and evaluation models,aimed at improving their robustness and reliability.Additionally,by identifying low-risk and high-return areas,resource allocation for geologic hazard prevention and control can be optimized,thus ensuring that limited resources are directed toward the most effective prevention and control measures.
基金supported by the National Natural Science Foundation of China(Project No.52074123).
文摘To explore the effects of freeze‒thaw cycles on the mechanical properties and crack evolution of fissured sandstone,biaxial compression experiments were carried out on sandstone subjected to freeze‒thaw cycles to characterize the changes in the physical and mechanical properties of fissured sandstone caused by freeze‒thaw cycles.The crack evolution and crack change process on the surface of the fissured sandstone were recorded and analysed in detail via digital image technology(DIC).Numerical simulation was used to reveal the expansion process and damage mode of fine-scale cracks under the action of freeze‒thaw cycles,and the simulation results were compared and analysed with the experimental data to verify the reliability of the numerical model.The results show that the mass loss,porosity,peak stress and elastic modulus all increase with increasing number of freeze‒thaw cycles.With an increase in the number of freeze‒thaw cycles,a substantial change in displacement occurs around the prefabricated cracks,and a stress concentration appears at the crack tip.As new cracks continue to sprout at the tips of the prefabricated cracks until the microcracks gradually penetrate into the main cracks,the displacement cloud becomes obviously discontinuous,and the contours of the displacement field in the crack fracture damage area simply intersect with the prefabricated cracks to form an obvious fracture.The damage patterns of the fractured sandstone after freeze‒thaw cycles clearly differ,forming a symmetrical"L"-shaped damage pattern at zero freeze‒thaw cycles,a symmetrical"V"-shaped damage pattern at 10 freeze‒thaw cycles,and a"V"-shaped damage pattern at 20 freeze‒thaw cycles.After 20 freeze‒thaw cycles,a"V"-shaped destruction pattern and"L"-shaped destruction pattern are formed;after 30 freeze‒thaw cycles,an"N"-shaped destruction pattern is formed.This shows that the failure mode of fractured sandstone gradually becomes more complicated with an increasing number of freeze‒thaw cycles.The effects of freeze‒thaw cycles on the direction and rate of crack propagation are revealed through a temperature‒load coupled model,which provides an important reference for an in-depth understanding of the freeze‒thaw failure mechanisms of fractured rock masses.
基金supported by the National Natural Science Foundation of China(Nos.52204092 and 52274203).
文摘The damage evolution process of non-penetrating cracks often causes some unexpected engineering disasters.Gypsum specimens containing non-penetrating crack(s)are used to study the damage evolution and characteristics under cyclic loading.The results show that under cyclic loading,the relationship between the number of non-penetrating crack(s)and the characteristic parameters(cyclic number,peak stress,peak strain,failure stress,and failure strain)of the pre-cracked specimens can be represented by a decreasing linear function.The damage evolution equation is fitted by calibrating the accumulative plastic strain for each cycle,and the damage constitutive equation is proposed by the concept of effective stress.Additionally,non-penetrating cracks are more likely to cause uneven stress distribution,damage accumulation,and local failure of specimen.The local failure can change the stress distribution and relieve the inhibition of non-penetrating crack extension and eventually cause a dramatic destruction of the specimen.Therefore,the evolution process caused by non-penetrating cracks can be regarded as one of the important reasons for inducing rockburst.These results are expected to improve the understanding of the process of spalling formation and rockburst and can be used to analyze the stability of rocks or rock structures.
基金Supported by Guangdong Provincial Science and Technology Plan Project,No.2022A0505050065Guangdong Natural Science Foundation,No.2022A1515011632.
文摘BACKGROUND Laparoscopic hepatectomy is a proven safe and technically feasible approach for liver tumor resection,but laparoscopic anatomical SVIII resection(LASVIIIR)remains rarely reported due to poor accessibility,difficult exposure,and the deep-lying Glissonean pedicle.This study examined the safety,feasibility,and perio-perative outcomes of LASVIIIR via a middle hepatic fissure approach at our in-stitution.AIM To investigate the safety,feasibility,and perioperative outcomes of LASVIIIR via a middle hepatic fissure approach at our institution.METHODS From November 2017 to December 2022,all patients with a liver tumor who underwent LASVIIIR were enrolled.The perioperative outcomes and postope-rative complications were evaluated.RESULTS Thirty-four patients underwent LASVIIIR via a middle hepatic fissure approach from the side or cranio side and were included.The mean operation time was 164±54 minutes,and the intra-operative blood loss was 100 mL(range:20-1000 mL).The mean operative times were,respectively,152±50 minutes and 222±29 minutes(P=0.001)for the caudal side and cranial side approaches.In addition,the median blood loss volumes were 100 mL(range:20-300 mL)and 250 mL(range:20-1000 mL),respectively,for the caudal and cranial sides(P=0.064).Three patients treated using the cranial side approach experienced bile leakage,while 1 patient treated using the caudal side approach had subphrenic collection and underwent percutaneous drainage to successfully recover.There were no differences regarding postoperative hospital stays for the caudal and cranial side approaches[9(7-26)days vs 8(8-19)days](P=0.226).CONCLUSION LASVIIIR resection remains a challenging operation,but the middle hepatic fissure approach is a reasonable and easy-to-implement technique.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.41972283)the Fundamental Research Funds for the Central Universities of Central South University(Grant No.2021zzts0287)the China Scholarship Council(Grant No.202206370109).
文摘In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads.In this paper,the dynamic behaviors and fracture characteristics of red sandstone considering temperatures(25℃,200℃,400℃,600℃,and 800℃)and fissure angles(0°,30°,60°,and 90°)were evaluated under constant-amplitude and low-cycle(CALC)impacts actuated by a modified split Hopkinson pressure bar(SHPB)system.Subsequently,fracture morphology and second-order statistics within the grey-level co-occurrence matrix(GLCM)were examined using scanning electron microscopy(SEM).Meanwhile,the deep analysis and discussion of the mechanical response were conducted through the synchronous thermal analyzer(STA)test,numerical simulations,one-dimensional stress wave theory,and material structure.The multiple regression models between response variables and interactive effects of independent variables were established using the response surface method(RSM).The results demonstrate the fatigue strength and life diminish as temperatures rise and increase with increasing fissure angles,while the strain rate exhibits an inverse behavior.Furthermore,the peak stress intensification and strain rate softening observed during CALC impact exhibit greater prominence at increased fissure angles.The failure is dominated by tensile damage with concise evolution paths and intergranular cracks as well as the compressor-crushed zone which may affect the failure mode after 400℃.The second-order statistics of GLCM in SEM images exhibit a considerable dependence on the temperatures.Also,thermal damage dominated by thermal properties controls the material structure and wave impedance and eventually affects the incident wave intensity.The tensile wave reflected from the fissure surface is the inherent mechanism responsible for the angle effect exhibited by the fatigue strength and life.Ultimately,the peak stress intensification and strain rate softening during impact are determined by both the material structure and compaction governed by thermal damage and tensile wave.
文摘Anal pruritus is a common anorectal symptom that can significantly impair a patient’s quality of life,including their mental health.It can be one of the most difficult proctological conditions to treat.Patients often delay seeking medical attention,since it is an embarrassing but non-life-threatening situation.Pruritus ani can be associated with idiopathic and secondary causes,such as anorectal diseases,cancer(anal or colorectal),dermatological and sexually transmitted diseases,fungal infections and systemic diseases.If patients are referred for a colonoscopy,this can sometimes provide the first opportunity to evaluate the perianal area.Classifications of anal pruritus are based on the abnormalities of the perianal skin,one of the most commonly used being the Washington classi-fication.A proper digital anorectal examination is important,as well as an anoscopy to help to exclude anorectal diseases or suspicious masses.Endoscopists should be aware of the common etiologies,and classification of the perianal area abnormalities should be provided in the colonoscopy report.Information on treatment possibilities and follow-up can also be provided.The treatment normally consists of a triple approach:proper hygiene,elimination of irritants,and skin care and protection.Several topical therapies have been described as possible treatments,including steroids,capsaicin,tacrolimus and methylene blue intradermal injections.
基金funded by the National Science Foundation of China(Nos.2022XAGG0400,42207202,42293351)the Open Fund of the Key Laboratory of Earth Fissures Geological Disaster,Ministry of Natural Resources,Geological Survey of Jiangsu Province,China(No.EFGD20240604)+2 种基金the Open Fund of the Observation and Research Station of Ground Fissure and Land Subsidence,Ministry of Natural Resources(No.GKF2024-06)the Fundamental Research Funds for the Central Universities of China University of Geosciences,Beijing(No.2-9-2021-014)the Fundamental Research Funds for the Central Universities of Chang'an University(No.300102264501-01)。
文摘Nearly 1100 fissures have formed on the Hebei Plain in China.Within the Yellow RiverQinghe River-Zhanghe River shallow buried paleochannel band on the plain,93 ground fissures controlled by paleochannels have developed,of which the Wuyi-Fuping ground fissure is a typical paleochannel-controlled fissure located in Hengshui,Hebei Province,with a total length of 3 km,a dominant strike of NE78°,and nearly upright in the shallow layer.The surface damage observed in this fissure primarily manifests as beaded pits,and its activity shows distinct segmentation characteristics.On the trench profiles,the offset distance of shallow layers remains consistently around 20 cm within the depth range of 0 to-3 m.An evident flexure is observed in the strata at depths ranging from-4.5 to-7 m.The drilling profile reveals that there is an absence of dislocations in the deeper strata.Nonetheless,the shallow seismic physical profiles unveil the presence of underlying faults beneath the study area,underscoring the intricate formation process and genesis mechanism of the Wuyi-Fuping ground fissure.Firstly,the formation and evolution of the Qingling River's paleochannel were shaped by the actions of fault blocks and underlying faults.The interplay of the regional stress field,fault block movement,and fault activity played pivotal roles in driving the development of this paleochannel.Secondly,the paleochannel exerts a controlling influence on the development location and severity of the fissure.During pumping,the confined aquifer within the paleochannel undergoes water loss and compression,resulting in the formation of a surface subsidence funnel.When the tensile stress surpasses the soil's tensile strength at the funnel's edge,the soil fractures give rise to a ground fissure.Finally,large amounts of surface water generated by heavy rainfall and irrigation can cause existing hidden ground fissures to rupture,emerge,and expand.This paper provides a heretofore generally unknown example,promotes research on the mechanisms of paleochannel-controlled fissures,and has guiding significance for disaster prevention and reduction in this area.
基金supported by the Major Program of the National Natural Science Foundation of China(No.52394191)the Fundamental Research Funds for China University of Mining and Technology(Beijing):Doctoral Top-notch Innovative Talents Cultivation Fund(No.BBJ2023018,BBJ2023023)the Open Fund of State Key Laboratory of Water Resource Protection and Utilization in Coal Mining(No.GJNY-20-113-20).
文摘The Inner Mongolia mining area in western China are characterized by the development of numerous penetrating fissures,resulting in severe land damage.It is significant to reveal the underlying evolution mechanism and identify treatment timing for restoring the ecological environment.The Guanbanwusu mining subsidence area in Inner Mongolia,China was selected as the research case for this study.The evolution mechanism of different penetrating fissures was revealed by field measurement,physical simulation and theoretical analysis.The treatment timing prediction model for the mining subsidence area was established based on the enhanced Weibull time function.The results show that the ground fissures are mainly step-type and collapse-type fissures.The breaking form of overlying strata determines their vertical opening and horizontal dislocation.The high mining intensity in the western mining area results in a shortened period of dynamic fissure expansion and reduced closure degree.The damage extent of the overlying strata exhibits zoning characteristics both vertically and horizontally.The relative standard deviation of the prediction model is only 3.7%.Concurrently,the prediction model is employed to determine the optimal timing for treatment in the study area,estimated to be 259 days.Subsequently,once this threshold is reached,the study area undergoes treatment and restoration of its e cological environment.This study addresses the knowledge gap in this field by highlighting the interconnectedness between rock strata structure and evolution mechanism of penetrating fissures,thereby providing a method for determining the treatment timing in mining subsidence areas.
