This article examines the development of geomorpho-logical and hydrological research on karst landscapes in Central and Southeast Europe in the period before 1914.It provides novel insights into the introduction of th...This article examines the development of geomorpho-logical and hydrological research on karst landscapes in Central and Southeast Europe in the period before 1914.It provides novel insights into the introduction of the term“karst,”originally the name of a cavernous limestone plateau east of the Adriatic city of Trieste,as a universal model for comparing and understanding dissolutional features in soluble rocks.Based on a critical reappraisal of the sem-inal work“The Karst Phenomenon”(1893)by the Serbian geoscientist Jovan Cvijić(1865-1928),submitted as a Ph.D.thesis at the University of Vienna,my essay argues for a reassessment of the beginnings of karst sciences.It gives more attention to research as a cooperative enterprise and to the interplay between the internationalization of geosci-entific knowledge and the emerging national claims to the Balkan Peninsula and its inhabitants.Approaching the topic from a history of science perspective,I will analyze the epistemic,political,and social dimensions of early karst research at three different stages,namely,its emergence as an imperial undertaking in the Habsburg Monarchy,its synthesis and systematization through Cvijić’s“Karst Phenomenon,”and the final establishment of the Dinarides’northwestern part as the“Classical”Karst.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
Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what exten...Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what extent CO_(2)fertilization affects vegetation changes in such regions remains unclear.In this study,we investigated the degree to which CO_(2)fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression analysis.Results showed that CO_(2)fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO_(2)fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau region.Previous studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these changes.The findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.展开更多
The mountainous rural regions of China are undergoing enormous changes in space and time.To a certain extent,this change has increased the difficulties in our understanding of rural development in mountainous areas an...The mountainous rural regions of China are undergoing enormous changes in space and time.To a certain extent,this change has increased the difficulties in our understanding of rural development in mountainous areas and brought challenges to development policies and revitalization strategies in mountainous rural regions,especially in karst mountainous areas.In light of the difficulty in and as the key to the development of China's mountainous rural areas,the scientific and systematic construction of indicators for evaluating the level of rural revitalization development and clarifying the level of rural revitalization development and influential factors in karst mountainous areas are of great significance to the implementation of the development of the strategy for the revitalization of the rural areas in karst mountainous areas in China.This study constructed an evaluation index system of the rural regional system and rural revitalization development(RTSRD)from the perspective of rural regional system theory,assessed the spatial differentiation patterns and influential factors of RTSRD,and refined a typical territorial model of rural revitalization development in karst mountainous areas by taking Guizhou Province,a typical karst mountainous region,as a case study area.The evaluation and spatial analyses show that the RTSRD indices of karst mountainous areas in the system perspective show a linear growth trend in all single dimensions,with industrial revitalization(IR)showing the most significant increase each year.In time,the RTSRD of karst mountainous regions has developed from low to high,with evident improvement;spatially,the RTSRD shows the characteristics of‘high in the middle and low in the surroundings,and low in the plateau and low in the depression,'with apparent spatial heterogeneity.In addition,this study found that the spatial and temporal differences in RTSRD result from a combination of endogenous push and exogenous pull in the rural system.In particular,this study has refined a typical regional model of rural revitalization development in karst mountainous regions,which provides theoretical support and case practice for rural development in other karst mountainous regions.At the same time,it provides a basis for decision-making for the county level government and rural development planning.展开更多
Karst fractures serve as crucial seepage channels and storage spaces for carbonate natural gas reservoirs,and electrical image logs are vital data for visualizing and characterizing such fractures.However,the conventi...Karst fractures serve as crucial seepage channels and storage spaces for carbonate natural gas reservoirs,and electrical image logs are vital data for visualizing and characterizing such fractures.However,the conventional approach of identifying fractures using electrical image logs predominantly relies on manual processes that are not only time-consuming but also highly subjective.In addition,the heterogeneity and strong dissolution tendency of karst carbonate reservoirs lead to complexity and variety in fracture geometry,which makes it difficult to accurately identify fractures.In this paper,the electrical image logs network(EILnet)da deep-learning-based intelligent semantic segmentation model with a selective attention mechanism and selective feature fusion moduledwas created to enable the intelligent identification and segmentation of different types of fractures through electrical logging images.Data from electrical image logs representing structural and induced fractures were first selected using the sliding window technique before image inpainting and data augmentation were implemented for these images to improve the generalizability of the model.Various image-processing tools,including the bilateral filter,Laplace operator,and Gaussian low-pass filter,were also applied to the electrical logging images to generate a multi-attribute dataset to help the model learn the semantic features of the fractures.The results demonstrated that the EILnet model outperforms mainstream deep-learning semantic segmentation models,such as Fully Convolutional Networks(FCN-8s),U-Net,and SegNet,for both the single-channel dataset and the multi-attribute dataset.The EILnet provided significant advantages for the single-channel dataset,and its mean intersection over union(MIoU)and pixel accuracy(PA)were 81.32%and 89.37%,respectively.In the case of the multi-attribute dataset,the identification capability of all models improved to varying degrees,with the EILnet achieving the highest MIoU and PA of 83.43%and 91.11%,respectively.Further,applying the EILnet model to various blind wells demonstrated its ability to provide reliable fracture identification,thereby indicating its promising potential applications.展开更多
In Southwestern China,the development of karst landforms and planation surfaces is closely related to local tectonics,fluvial incision,and base level changes,and climate changes.However,researches on when these karst ...In Southwestern China,the development of karst landforms and planation surfaces is closely related to local tectonics,fluvial incision,and base level changes,and climate changes.However,researches on when these karst landforms and planation surfaces formed and how they evolved along drainage development are scarce.Fortunately,horizontal caves with numerous fluvial deposits in high karst mountains can be served as time markers in landform evolution.Here we select large horizontal caves to perform studies of geomorphology,sedimentology,and geochronology.Fieldwork revealed that more than 25 km long horizontal cave passages are perched 1500 m higher than the local base level,but filled with several phases of fluvial sediments and breakdown slabs.The first phase of fluvial gravels and related cave drainage was dated back to 6.4 Ma using cosmogenic nuclide burial dating,and the stalagmite covering the cave collapse was dated by the U-Pb method to be older than 1.56 Ma.These results show that the continuous horizontal cave drainage system and the planation surface were developed before the Late Miocene.The lowering process of the base level as a result of the sharp fluvial incision and water level lowering,along with the regional uplift,led to the abandonment of the horizontal cave and the elevated planation surface at the Late Miocene.After that,the phase of cave collapse,thick fluvial sand,and clay sediments in the recharge of cave areas were deposited at around 1.6 Ma and during the Middle Pleistocene,respectively.Subsequently,speleothems were widely deposited on the collapse and clay sediments during the period from 600 to 90 ka,whereas the deposition of cave fluvial sediments terminated suddenly.The tectonic could control the denudation of surface caprocks and the development of karst conduits before the Late Miocene,whereas the river incision acted as the main driver for the base level lowering and the destruction of the horizontal cave drainage at high altitudes.In addition,the rapid incision and retreat of Silurian gorges finally caused the formation of karst mesas in the Middle Pleistocene.展开更多
Economic development,food security,and ecological preservation are important issues encountered by karst re-gions.Faced with complex natural and social dynamics,we attempted to explore how interdependence within socio...Economic development,food security,and ecological preservation are important issues encountered by karst re-gions.Faced with complex natural and social dynamics,we attempted to explore how interdependence within socio-ecological system(SES)shaped sustainability in this region.A SES framework was constructed and three scenarios were predesigned:economic priority scenario,food security scenario,and ecological protection sce-nario.The System Dynamics model was used to simulate and forecast the evolution across various scenarios within the SES from 2005 to 2035.Through the Production-Possibility Frontiers in combined scenarios,trade-offpotential was identified and quantified.The results showed that the decoupling between social and ecological subsystems can be weaken in economic priority scenario,while coupling between them can be strengthen in food security scenario and ecological protection scenario.Within the SES,combined scenario analyses further suggest that the rocky desertification rate and the urban-rural income ratio exhibit the least trade-offpotential and inten-sity in combined economic priority scenario and ecological protection scenario,and the Soil Conservation and Food Supply demonstrate the least trade-offpotential and intensity in combined economic priority scenario and food security scenario.We can conclude the ecological engineering plays a significant role in alleviating trade-offs within the SES,but the effectiveness is limited.In light of intertwined socio-ecological challenges,combining ecological engineering with adaptive adjustments is a crucial strategy to enhance SES resilience and promote sustainable development in the South China Karst.展开更多
[Objectives] To investigate the species diversity of wood-decaying fungi in karst regions of southwest China. [Methods] The karst core regions of southwest China, specifically Guizhou, Guangxi, and Yunnan, were invest...[Objectives] To investigate the species diversity of wood-decaying fungi in karst regions of southwest China. [Methods] The karst core regions of southwest China, specifically Guizhou, Guangxi, and Yunnan, were investigated for the first time to analyze the species diversity characteristics of wood-decaying fungi in this area. This analysis was conducted through a comprehensive 5-year field investigation and systematic identification process. [Results] The wood-decaying fungi exhibited a distinctive species composition and distribution pattern within karst habitats, encompassing significant groups such as Polyporaceae and Hymenochaetaceae. Furthermore, these fungi demonstrated varying functional characteristics across the two ecological types of standing tree decay and wood decay. It was observed that wood-decaying fungi had a significant impact on the material cycle within karst ecosystems by degrading lignin and cellulose. Furthermore, the distribution of species diversity was closely associated with the characteristics of karst geomorphology and the types of vegetation. [Conclusions] This study not only addresses the lack of background data regarding wood-decaying fungi resources in karst regions, but also elucidates the maintenance mechanisms of fragile ecosystems from the perspective of decomposers. It provides a scientific foundation for biodiversity conservation, the prevention and control of forest diseases, and sustainable ecological management in karst regions.展开更多
The water conductivity of karst collapsed column is affected by multiple factors such as the characteristics of its own column filling,structure and mining disturbance.As a structural water-conducting channel,fault us...The water conductivity of karst collapsed column is affected by multiple factors such as the characteristics of its own column filling,structure and mining disturbance.As a structural water-conducting channel,fault usually plays a controlling role in hydrogeological structure.During the process of mine water hazard prevention and control,it was discovered that the lithology composition,compaction and cementation degree and water physical properties of karst collapsed column fillings were all non-conducting water,but due to the influence of combined development faults,some exploration drill holes showed concentrated water outflow.Based on this,the scientific hypothesis was proposed that fault cutting leads to water conduction in karst collapsed columns.The study comprehensively used methods like chronology,exploration data analysis,and hydrochemical testing to analyze the chronological relationship between faults and karst collapsed columns,their spatial relationship,outlet point distribution and water chemical properties,and the impact of faults on the water-conductivity of karst collapsed columns,which proved the effect of fault cutting on changing water conductivity of karst collapsed column.The research showed that later fault cutting through karst collapsed columns turned the originally non-conductive karst collapsed columns into water-conductive collapsed columns at the fault plane,creating a longitudinally connected water-conducting channel.A new model of fault cutting karst collapsed column to change the original water conductivity of karst collapsed column was proposed.The research results can provide a theoretical basis for the prediction of the water conductivity of the karst collapsed column.According to whether the karst collapsed column was cut by the fault,it was predicted theoretically,so as to determine the key areas of water conductivity detection and prevention and control,and has broad application prospects under the background of source control of mine water disaster.展开更多
Fixed supports(rigid structures)and flexible supports(tensioned cable systems)are two main methods used in constructing photovoltaic power plants,and their construction technology has significant differences.This comp...Fixed supports(rigid structures)and flexible supports(tensioned cable systems)are two main methods used in constructing photovoltaic power plants,and their construction technology has significant differences.This comparative study assessed their environmental impacts on near-surface characteristics during constructing photovoltaic power plants in karst mountainous regions.Our findings revealed significant but different surface disturbances between these installation approaches.While both systems caused terrain modifications through foundation works and access road construction,the fixed support completely disturbed 100%of the construction area compared to<30%disturbance from flexible supports.Compared with the original ground,fixed support caused approximately 22%increase in bedrock exposure rate,while decreased 5%for the flexible support.Additionally,only 17%of the original vegetation coverage remained for the fixed support after construction,compared to 53%for the flexible support.The lower bedrock exposure rate and higher vegetation coverage of flexible support indicated that it had less surface disturbance area than fixed support.These results suggested that in ecologically sensitive karst terrains characterized by severe rocky desertification,challenging revegetation conditions,and low land productivity,flexible support photovoltaic technology represented a significantly less disruptive technology for minimizing surface disturbance and preserving fragile mountain ecosystems.展开更多
Developing hydrothermal resources in highly conductive karst aquifers at deep mine floors is regarded as a potential approach to achieving the co-development of coal and geothermal resources.However,the heat transfer ...Developing hydrothermal resources in highly conductive karst aquifers at deep mine floors is regarded as a potential approach to achieving the co-development of coal and geothermal resources.However,the heat transfer potential of the fracture system in the target reservoir under mining activities remains in suspense.Hence,a coupled thermal-hydraulic-mechanical model was developed for the karst reservoir of Anju coal mine in China,considering non-isothermal convective heat transfer in fractures.This model examined the influence of stress redistribution due to different mining distances(MD)on the effective flow channel length/density and the high/low-aperture fracture distribution.The dynamic heat generation characteristics of the geothermal reservoir were evaluated.Key findings include:Mining-induced stress creates interlaced high-aperture and low-aperture fracture zones below the goaf.Within these interlaced zones,the combined effect of high-and low-aperture fractures restricts the effective flow channel length/density of the fracture network.This contraction of the flow field leads to a significant decline in production flow rate,which consequently reduces both the production flow rate and power as MD increases.This work represents the study of mining disturbances on geothermal production,providing a theoretical foundation for the co-development of coal and geothermal resources.展开更多
Ecological security provides the basis of maintaining both a sustainable regional ecosystem and economic development.However,few studies have focused on how the features such as topography and geomorphology,lithologic...Ecological security provides the basis of maintaining both a sustainable regional ecosystem and economic development.However,few studies have focused on how the features such as topography and geomorphology,lithologic stratigraphic assemblages,and geohazard distribution affect the construction of ecological security patterns and the layout of optimization measures.In order to comprehensively reveal the key areas and key objects of ecological restoration in karst basins,this study takes the Beipan River Basin(BRB)as an example,constructs an ecological security pattern(ESP)based on the methods of morphological spatial pattern analysis(MSPA),landscape connectivity analysis and circuit theory,and lays out the optimization measures in combination with the spatial distribution characteristics of topographic and geomorphological differences and lithological stratigraphic combinations.The results show that 151 ecological sources,343 ecological corridors,121 pinch points and 178 barriers constitute the ESP of the BRB.Lithology is closely related to the spatial distribution characteristics of ecological source sites.Level 1 and 2 ecological sources(The ecological sources were categorized into level 1,level 2,and level 3 source from high to low importance.)are concentrated in the Emeishan basalt region of the upstream and the clastic and impure carbonate rock region of the downstream part of the BRB;level 3ecological sources are concentrated in the carbonate rock region of the midstream.Taking into account the outstanding ecological problems in the basin,and based on the characteristics of lithology and geohazard distribution,we propose the optimization scheme of“three axes,three zones and multiple points”for the ESP and the layout of specific measures of the BRB.The results can provide scientific references for maintaining ecological security maintenance in karst ecologically fragile areas.展开更多
The karst forest in southwestern China is characterized by thin soil layers,numerous fissures and holes,resulting in low soil water availability and poor water retention,making it challenging for plant growth and surv...The karst forest in southwestern China is characterized by thin soil layers,numerous fissures and holes,resulting in low soil water availability and poor water retention,making it challenging for plant growth and survival.While the relationship between plant functional traits and tree growth performance has been extensively studied,the links between tree seasonal growth and drought-tolerant traits in tree species with different leaf habit remains poorly understood.This study evaluated the associations between four-year averaged rainy season stem diameter growth rate and 17 branch and leaf traits across evergreen and deciduous species in a tropical karst forest in southwest China.The cross-species variations in tree growth rates were related to plant hydraulic traits(e.g.,vessel lumen diameter,xylem vessel density,stomatal density,and stomatal size)and leaf anatomical traits(e.g.,total leaf thickness,lower/upper epidermis thickness,and spongy thickness).The growth of evergreen trees exhibited lower hydraulic efficiency but greater drought tolerance than deciduous tree,which enabled them to maintain higher persistence under low soil water availability and consequently a relatively longer growing season.In contrast,deciduous species showed no correlation between their functional traits and growth rate.The distinct water use strategies of evergreen and deciduous trees may offer a potential explanation for their co-existence in the tropical karst forests.展开更多
Karst caves are among the most common and critical geological hazards in karst regions.Due to their marked differences in physical properties compared to the surrounding rock,they can be detected using various geophys...Karst caves are among the most common and critical geological hazards in karst regions.Due to their marked differences in physical properties compared to the surrounding rock,they can be detected using various geophysical techniques.Karsts have developed on the surface of the Qingshuitang Wollastonite Mining Area in Huangtian Town,Hezhou City,Guangxi Province.In line with mine safety production requirements,a professional assessment of the potential development of karst caves must be conducted within 150 m of the mining area’s surface.Following an on-site investiga-tion and comparison with traditional geophysical methods,seismic frequency resonance technology(Seismic FRT)was selected for detection due to its convenience,flexibility,cost-effectiveness,and rapid data acquisition capabilities.Contour maps of the apparent wave impedance and geological profiles along the survey lines were obtained through data collection and processing.In combination with surface karst and mining geology,32 karst caves(hidden danger points)and 15 karst development zones were identified.Drilling verification was conducted at the A428 and B122 anomalous points on the A1# and B1# survey lines.The verification results were consistent with the inferred depths and maximum apparent wave impedance anomalies,confirming that Seismic FRT is a feasible and effective method for detecting hid-den karst development areas in mines.展开更多
Tufa is an important type of landscape in karst regions.In recent years,the loss of landscape diversity due to tufa dissolution is affecting the stability of local ecosystems.Therefore,determining the factors and thei...Tufa is an important type of landscape in karst regions.In recent years,the loss of landscape diversity due to tufa dissolution is affecting the stability of local ecosystems.Therefore,determining the factors and their mechanisms involved in tufa dissolution is important for preserving regional landscape diversity and local ecosystem stability.In this study,we selected four tufa sites with different degrees of dissolution(undissolved tufa,lightly dissolved tufa,moderately dissolved tufa,and heavily dissolved tufa)in Xiangzhigou karst region of Guizhou Province as the study objects.We explored the effects of natural plant colonization on tufa dissolution using changes inαandβdiversity indices,soil physicochemical indicators,tufa components,and tufa substrate.The results indicated that the Shannon-wiener index,Simpson index and Patrick richness index gradually increased with tufa's increasing degree of dissolution.Additionally,the dissolution degree exhibited a significantly negative correlation with the species diversity(p<0.05).Natural vegetation colonization is the primary cause of changes in the proportion of tufa components and changes in the physicochemical properties of overlying tufa soils.The proportion of CaO components decreased significantly,and the proportion of loss on ignition components increased significantly.Soil organic carbon,pH,total nitrogen,available nitrogen,total phosphorus,available phosphorus,total potassium,available potassium,β-glucosidase,and urease gradually increased with deeper tufa dissolution and were negatively correlated with the degree of dissolution(p<0.05).It indicates that tufa is a process of dissolution into the soil and gradual improvement of the physicochemical properties of the overlying soil.Furthermore,scanning electron micrographs revealed the transition from dense to fragmented tufa structure under the influence of plants.In conclusion,this study found that improving plant diversity exacerbated tufa dissolution.Our findings provide a theoretical reference for the preventing and controlling of tufa dissolution in karst.展开更多
Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the ...Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.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
Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of ...Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of dolines.In this research,doline susceptibility map was prepared in Saldaran mountain by generalized linear model(GLM)using 14 affecting parameters extracted from satellite images,digital elevation model,and geology map.Only 8 parameters have been inputted to the model which had correlation with dolines.In this regards,306 dolines were identified by the photogrammetric Unmanned Aerial Vehicles(UAV)method in 600 hectares of Salderan lands and then,these data were divided into the training(70%)and testing(30%)data for modelling.The results of DSM modeling showed that classified probability of doline occurrences in the Saldaran mountain were as follow:16.5%of the area high to very high,72%in the class of low to very low,and 5%in the moderate class.Also,locally,in Saldaran mountain,the Pirghar aquifer has the highest potential for the doline development,followed by Bagh Rostam and Sarab aquifers.Also,the precipitation,digital elevation model,Topographic Position Index,drainage density,slope,TRASP(transformed the circular aspect to a radiation index),Snow-Covered Days and vegetation cover index are of highest importance in the DSM modeling,respectively.Accurate evaluation of the model using the Receiver Operating Characteristics(ROC)curve represents a very good accuracy(AUC=0.953)of the DSM model.展开更多
Karst collapse columns typically appear unpredictably and without a uniform spatial arrangement,posing challenges for mining operations and water inrush risk assessment.As major structural pathways for mine water inru...Karst collapse columns typically appear unpredictably and without a uniform spatial arrangement,posing challenges for mining operations and water inrush risk assessment.As major structural pathways for mine water inrush,they are responsible for some of the most frequent and severe water-related disasters in coal mining.Understanding the mechanisms of water inrush in these collapse columns is therefore essential for effective disaster prevention and control,making it a key research priority.Additionally,investigating the developmental characteristics of collapse columns is crucial for analyzing seepage instability mechanisms.In such a context,this paper provides a comprehensive review of four critical aspects:(1)The development characteristics and hydrogeological properties of collapse columns;(2)Fluid-solid coupling mechanisms under mining-induced stress;(3)Non-Darcy seepage behavior in fractured rock masses;(4)Flow regime transitions and mass variation effects.Key findings highlight the role of flow-solid coupling in governing the seepage mechanisms of fractured rock masses within karst collapse columns.By synthesizing numerous studies on flow pattern transitions,this paper outlines the complete seepage process-from groundwater movement within the aquifer to its migration through the collapse column and eventual inflow into mine roadways or working faces-along with the associated transformations in flow patterns.Furthermore,the seepage characteristics and water inrush behaviors influenced by particle migration are examined through both experimental and numerical simulation approaches.展开更多
文摘This article examines the development of geomorpho-logical and hydrological research on karst landscapes in Central and Southeast Europe in the period before 1914.It provides novel insights into the introduction of the term“karst,”originally the name of a cavernous limestone plateau east of the Adriatic city of Trieste,as a universal model for comparing and understanding dissolutional features in soluble rocks.Based on a critical reappraisal of the sem-inal work“The Karst Phenomenon”(1893)by the Serbian geoscientist Jovan Cvijić(1865-1928),submitted as a Ph.D.thesis at the University of Vienna,my essay argues for a reassessment of the beginnings of karst sciences.It gives more attention to research as a cooperative enterprise and to the interplay between the internationalization of geosci-entific knowledge and the emerging national claims to the Balkan Peninsula and its inhabitants.Approaching the topic from a history of science perspective,I will analyze the epistemic,political,and social dimensions of early karst research at three different stages,namely,its emergence as an imperial undertaking in the Habsburg Monarchy,its synthesis and systematization through Cvijić’s“Karst Phenomenon,”and the final establishment of the Dinarides’northwestern part as the“Classical”Karst.
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.
基金National Natural Science Foundation of China,No.41761003The Karst Science Research Center of Guizhou Province,No.U1812401。
文摘Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what extent CO_(2)fertilization affects vegetation changes in such regions remains unclear.In this study,we investigated the degree to which CO_(2)fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression analysis.Results showed that CO_(2)fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO_(2)fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau region.Previous studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these changes.The findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.
基金supported by the National Natural Science Foundation of China(Grant No.42061035)the Guizhou Provincial Program on Commercialization of Scientific and Technological Achievements([2022]010)。
文摘The mountainous rural regions of China are undergoing enormous changes in space and time.To a certain extent,this change has increased the difficulties in our understanding of rural development in mountainous areas and brought challenges to development policies and revitalization strategies in mountainous rural regions,especially in karst mountainous areas.In light of the difficulty in and as the key to the development of China's mountainous rural areas,the scientific and systematic construction of indicators for evaluating the level of rural revitalization development and clarifying the level of rural revitalization development and influential factors in karst mountainous areas are of great significance to the implementation of the development of the strategy for the revitalization of the rural areas in karst mountainous areas in China.This study constructed an evaluation index system of the rural regional system and rural revitalization development(RTSRD)from the perspective of rural regional system theory,assessed the spatial differentiation patterns and influential factors of RTSRD,and refined a typical territorial model of rural revitalization development in karst mountainous areas by taking Guizhou Province,a typical karst mountainous region,as a case study area.The evaluation and spatial analyses show that the RTSRD indices of karst mountainous areas in the system perspective show a linear growth trend in all single dimensions,with industrial revitalization(IR)showing the most significant increase each year.In time,the RTSRD of karst mountainous regions has developed from low to high,with evident improvement;spatially,the RTSRD shows the characteristics of‘high in the middle and low in the surroundings,and low in the plateau and low in the depression,'with apparent spatial heterogeneity.In addition,this study found that the spatial and temporal differences in RTSRD result from a combination of endogenous push and exogenous pull in the rural system.In particular,this study has refined a typical regional model of rural revitalization development in karst mountainous regions,which provides theoretical support and case practice for rural development in other karst mountainous regions.At the same time,it provides a basis for decision-making for the county level government and rural development planning.
基金the National Natural Science Foundation of China(42472194,42302153,and 42002144)the Fundamental Research Funds for the Central Univer-sities(22CX06002A).
文摘Karst fractures serve as crucial seepage channels and storage spaces for carbonate natural gas reservoirs,and electrical image logs are vital data for visualizing and characterizing such fractures.However,the conventional approach of identifying fractures using electrical image logs predominantly relies on manual processes that are not only time-consuming but also highly subjective.In addition,the heterogeneity and strong dissolution tendency of karst carbonate reservoirs lead to complexity and variety in fracture geometry,which makes it difficult to accurately identify fractures.In this paper,the electrical image logs network(EILnet)da deep-learning-based intelligent semantic segmentation model with a selective attention mechanism and selective feature fusion moduledwas created to enable the intelligent identification and segmentation of different types of fractures through electrical logging images.Data from electrical image logs representing structural and induced fractures were first selected using the sliding window technique before image inpainting and data augmentation were implemented for these images to improve the generalizability of the model.Various image-processing tools,including the bilateral filter,Laplace operator,and Gaussian low-pass filter,were also applied to the electrical logging images to generate a multi-attribute dataset to help the model learn the semantic features of the fractures.The results demonstrated that the EILnet model outperforms mainstream deep-learning semantic segmentation models,such as Fully Convolutional Networks(FCN-8s),U-Net,and SegNet,for both the single-channel dataset and the multi-attribute dataset.The EILnet provided significant advantages for the single-channel dataset,and its mean intersection over union(MIoU)and pixel accuracy(PA)were 81.32%and 89.37%,respectively.In the case of the multi-attribute dataset,the identification capability of all models improved to varying degrees,with the EILnet achieving the highest MIoU and PA of 83.43%and 91.11%,respectively.Further,applying the EILnet model to various blind wells demonstrated its ability to provide reliable fracture identification,thereby indicating its promising potential applications.
基金supported by the foundation of the Institute of Karst Geology,Chinese Academy of Geological Sciences(Nos.201317,2014005,2014034,2016011)National Natural Science Foundation of China(No.41270226)。
文摘In Southwestern China,the development of karst landforms and planation surfaces is closely related to local tectonics,fluvial incision,and base level changes,and climate changes.However,researches on when these karst landforms and planation surfaces formed and how they evolved along drainage development are scarce.Fortunately,horizontal caves with numerous fluvial deposits in high karst mountains can be served as time markers in landform evolution.Here we select large horizontal caves to perform studies of geomorphology,sedimentology,and geochronology.Fieldwork revealed that more than 25 km long horizontal cave passages are perched 1500 m higher than the local base level,but filled with several phases of fluvial sediments and breakdown slabs.The first phase of fluvial gravels and related cave drainage was dated back to 6.4 Ma using cosmogenic nuclide burial dating,and the stalagmite covering the cave collapse was dated by the U-Pb method to be older than 1.56 Ma.These results show that the continuous horizontal cave drainage system and the planation surface were developed before the Late Miocene.The lowering process of the base level as a result of the sharp fluvial incision and water level lowering,along with the regional uplift,led to the abandonment of the horizontal cave and the elevated planation surface at the Late Miocene.After that,the phase of cave collapse,thick fluvial sand,and clay sediments in the recharge of cave areas were deposited at around 1.6 Ma and during the Middle Pleistocene,respectively.Subsequently,speleothems were widely deposited on the collapse and clay sediments during the period from 600 to 90 ka,whereas the deposition of cave fluvial sediments terminated suddenly.The tectonic could control the denudation of surface caprocks and the development of karst conduits before the Late Miocene,whereas the river incision acted as the main driver for the base level lowering and the destruction of the horizontal cave drainage at high altitudes.In addition,the rapid incision and retreat of Silurian gorges finally caused the formation of karst mesas in the Middle Pleistocene.
基金supported by the National Key Research and Develop-ment Program of China(Grant No.2022YFF1300701)the Sichuan Science and Technology Program(Grant No.2022JDJQ0015).
文摘Economic development,food security,and ecological preservation are important issues encountered by karst re-gions.Faced with complex natural and social dynamics,we attempted to explore how interdependence within socio-ecological system(SES)shaped sustainability in this region.A SES framework was constructed and three scenarios were predesigned:economic priority scenario,food security scenario,and ecological protection sce-nario.The System Dynamics model was used to simulate and forecast the evolution across various scenarios within the SES from 2005 to 2035.Through the Production-Possibility Frontiers in combined scenarios,trade-offpotential was identified and quantified.The results showed that the decoupling between social and ecological subsystems can be weaken in economic priority scenario,while coupling between them can be strengthen in food security scenario and ecological protection scenario.Within the SES,combined scenario analyses further suggest that the rocky desertification rate and the urban-rural income ratio exhibit the least trade-offpotential and inten-sity in combined economic priority scenario and ecological protection scenario,and the Soil Conservation and Food Supply demonstrate the least trade-offpotential and intensity in combined economic priority scenario and food security scenario.We can conclude the ecological engineering plays a significant role in alleviating trade-offs within the SES,but the effectiveness is limited.In light of intertwined socio-ecological challenges,combining ecological engineering with adaptive adjustments is a crucial strategy to enhance SES resilience and promote sustainable development in the South China Karst.
基金Supported by National Natural Science Foundation of China(31900271,32160086)Key Technology Research for Identification of Toxic Fungi in Guizhou Province(GKHZC[2020]1Y065)+1 种基金Guizhou Grassroots Science Popularization Action Plan Project([2025]04)Study on Carbon Storage and Carbon Sink Value of Forest Vegetation in State-owned Shatang Forest Farms in Guangxi(2021KY02).
文摘[Objectives] To investigate the species diversity of wood-decaying fungi in karst regions of southwest China. [Methods] The karst core regions of southwest China, specifically Guizhou, Guangxi, and Yunnan, were investigated for the first time to analyze the species diversity characteristics of wood-decaying fungi in this area. This analysis was conducted through a comprehensive 5-year field investigation and systematic identification process. [Results] The wood-decaying fungi exhibited a distinctive species composition and distribution pattern within karst habitats, encompassing significant groups such as Polyporaceae and Hymenochaetaceae. Furthermore, these fungi demonstrated varying functional characteristics across the two ecological types of standing tree decay and wood decay. It was observed that wood-decaying fungi had a significant impact on the material cycle within karst ecosystems by degrading lignin and cellulose. Furthermore, the distribution of species diversity was closely associated with the characteristics of karst geomorphology and the types of vegetation. [Conclusions] This study not only addresses the lack of background data regarding wood-decaying fungi resources in karst regions, but also elucidates the maintenance mechanisms of fragile ecosystems from the perspective of decomposers. It provides a scientific foundation for biodiversity conservation, the prevention and control of forest diseases, and sustainable ecological management in karst regions.
基金supported by the Postdoctoral Fellowship Program of CPSF(No.GZC20233005)the Fundamental Research Funds for the Central Universities(No.2024QN11025)+1 种基金the General Program of National Natural Science Foundation of China(No.52274243)the Hebei Province Natural Science Foundation Ecological Wisdom Mine Joint Fund Project(Nos.D2020402013 and D2022402040)。
文摘The water conductivity of karst collapsed column is affected by multiple factors such as the characteristics of its own column filling,structure and mining disturbance.As a structural water-conducting channel,fault usually plays a controlling role in hydrogeological structure.During the process of mine water hazard prevention and control,it was discovered that the lithology composition,compaction and cementation degree and water physical properties of karst collapsed column fillings were all non-conducting water,but due to the influence of combined development faults,some exploration drill holes showed concentrated water outflow.Based on this,the scientific hypothesis was proposed that fault cutting leads to water conduction in karst collapsed columns.The study comprehensively used methods like chronology,exploration data analysis,and hydrochemical testing to analyze the chronological relationship between faults and karst collapsed columns,their spatial relationship,outlet point distribution and water chemical properties,and the impact of faults on the water-conductivity of karst collapsed columns,which proved the effect of fault cutting on changing water conductivity of karst collapsed column.The research showed that later fault cutting through karst collapsed columns turned the originally non-conductive karst collapsed columns into water-conductive collapsed columns at the fault plane,creating a longitudinally connected water-conducting channel.A new model of fault cutting karst collapsed column to change the original water conductivity of karst collapsed column was proposed.The research results can provide a theoretical basis for the prediction of the water conductivity of the karst collapsed column.According to whether the karst collapsed column was cut by the fault,it was predicted theoretically,so as to determine the key areas of water conductivity detection and prevention and control,and has broad application prospects under the background of source control of mine water disaster.
基金supported by Technology Project of Power Construction Corporation of China(DJ-ZDXM-2023-07)。
文摘Fixed supports(rigid structures)and flexible supports(tensioned cable systems)are two main methods used in constructing photovoltaic power plants,and their construction technology has significant differences.This comparative study assessed their environmental impacts on near-surface characteristics during constructing photovoltaic power plants in karst mountainous regions.Our findings revealed significant but different surface disturbances between these installation approaches.While both systems caused terrain modifications through foundation works and access road construction,the fixed support completely disturbed 100%of the construction area compared to<30%disturbance from flexible supports.Compared with the original ground,fixed support caused approximately 22%increase in bedrock exposure rate,while decreased 5%for the flexible support.Additionally,only 17%of the original vegetation coverage remained for the fixed support after construction,compared to 53%for the flexible support.The lower bedrock exposure rate and higher vegetation coverage of flexible support indicated that it had less surface disturbance area than fixed support.These results suggested that in ecologically sensitive karst terrains characterized by severe rocky desertification,challenging revegetation conditions,and low land productivity,flexible support photovoltaic technology represented a significantly less disruptive technology for minimizing surface disturbance and preserving fragile mountain ecosystems.
基金supported by the National Natural Science Foundation of China(Nos.U23B2091,52304104,and 52404157)the National Key R&D Program of China(No.2022YFC2905600)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(No.GZB20240825).
文摘Developing hydrothermal resources in highly conductive karst aquifers at deep mine floors is regarded as a potential approach to achieving the co-development of coal and geothermal resources.However,the heat transfer potential of the fracture system in the target reservoir under mining activities remains in suspense.Hence,a coupled thermal-hydraulic-mechanical model was developed for the karst reservoir of Anju coal mine in China,considering non-isothermal convective heat transfer in fractures.This model examined the influence of stress redistribution due to different mining distances(MD)on the effective flow channel length/density and the high/low-aperture fracture distribution.The dynamic heat generation characteristics of the geothermal reservoir were evaluated.Key findings include:Mining-induced stress creates interlaced high-aperture and low-aperture fracture zones below the goaf.Within these interlaced zones,the combined effect of high-and low-aperture fractures restricts the effective flow channel length/density of the fracture network.This contraction of the flow field leads to a significant decline in production flow rate,which consequently reduces both the production flow rate and power as MD increases.This work represents the study of mining disturbances on geothermal production,providing a theoretical foundation for the co-development of coal and geothermal resources.
基金jointly supported by the Key Project of the Natural Science Foundation of Guizhou Province(No.Qiankehe Jichu-ZK[2023]Zhongdian027)the Project of the Science and Technology Innovation Base Construction of Guizhou Province(No.Qiankehe Zhongyindi[2023]005)Philosophy and Social Science Planning Subjects in Guizhou Province in 2022(No.22GZYB53)。
文摘Ecological security provides the basis of maintaining both a sustainable regional ecosystem and economic development.However,few studies have focused on how the features such as topography and geomorphology,lithologic stratigraphic assemblages,and geohazard distribution affect the construction of ecological security patterns and the layout of optimization measures.In order to comprehensively reveal the key areas and key objects of ecological restoration in karst basins,this study takes the Beipan River Basin(BRB)as an example,constructs an ecological security pattern(ESP)based on the methods of morphological spatial pattern analysis(MSPA),landscape connectivity analysis and circuit theory,and lays out the optimization measures in combination with the spatial distribution characteristics of topographic and geomorphological differences and lithological stratigraphic combinations.The results show that 151 ecological sources,343 ecological corridors,121 pinch points and 178 barriers constitute the ESP of the BRB.Lithology is closely related to the spatial distribution characteristics of ecological source sites.Level 1 and 2 ecological sources(The ecological sources were categorized into level 1,level 2,and level 3 source from high to low importance.)are concentrated in the Emeishan basalt region of the upstream and the clastic and impure carbonate rock region of the downstream part of the BRB;level 3ecological sources are concentrated in the carbonate rock region of the midstream.Taking into account the outstanding ecological problems in the basin,and based on the characteristics of lithology and geohazard distribution,we propose the optimization scheme of“three axes,three zones and multiple points”for the ESP and the layout of specific measures of the BRB.The results can provide scientific references for maintaining ecological security maintenance in karst ecologically fragile areas.
基金financially funded by the National Natural Science Foundation of China(3186113307,31770533,31870591)the West Light Talent Program of the Chinese Academy of Sciences(xbzg-zdsys-202218).
文摘The karst forest in southwestern China is characterized by thin soil layers,numerous fissures and holes,resulting in low soil water availability and poor water retention,making it challenging for plant growth and survival.While the relationship between plant functional traits and tree growth performance has been extensively studied,the links between tree seasonal growth and drought-tolerant traits in tree species with different leaf habit remains poorly understood.This study evaluated the associations between four-year averaged rainy season stem diameter growth rate and 17 branch and leaf traits across evergreen and deciduous species in a tropical karst forest in southwest China.The cross-species variations in tree growth rates were related to plant hydraulic traits(e.g.,vessel lumen diameter,xylem vessel density,stomatal density,and stomatal size)and leaf anatomical traits(e.g.,total leaf thickness,lower/upper epidermis thickness,and spongy thickness).The growth of evergreen trees exhibited lower hydraulic efficiency but greater drought tolerance than deciduous tree,which enabled them to maintain higher persistence under low soil water availability and consequently a relatively longer growing season.In contrast,deciduous species showed no correlation between their functional traits and growth rate.The distinct water use strategies of evergreen and deciduous trees may offer a potential explanation for their co-existence in the tropical karst forests.
基金supported by the General Project of Guangxi Natural Science Foundation grant number[2020GXNSFAA297088]the Hezhou Science Research and Development Plan Project grant number[2024143]the Basic Research Ability Enhancement Project for Young and Middle-aged Teachers at Guangxi Universities grant number[2024KY1877].
文摘Karst caves are among the most common and critical geological hazards in karst regions.Due to their marked differences in physical properties compared to the surrounding rock,they can be detected using various geophysical techniques.Karsts have developed on the surface of the Qingshuitang Wollastonite Mining Area in Huangtian Town,Hezhou City,Guangxi Province.In line with mine safety production requirements,a professional assessment of the potential development of karst caves must be conducted within 150 m of the mining area’s surface.Following an on-site investiga-tion and comparison with traditional geophysical methods,seismic frequency resonance technology(Seismic FRT)was selected for detection due to its convenience,flexibility,cost-effectiveness,and rapid data acquisition capabilities.Contour maps of the apparent wave impedance and geological profiles along the survey lines were obtained through data collection and processing.In combination with surface karst and mining geology,32 karst caves(hidden danger points)and 15 karst development zones were identified.Drilling verification was conducted at the A428 and B122 anomalous points on the A1# and B1# survey lines.The verification results were consistent with the inferred depths and maximum apparent wave impedance anomalies,confirming that Seismic FRT is a feasible and effective method for detecting hid-den karst development areas in mines.
基金the National Natural Science Foundation of China(Grant No:32360052)。
文摘Tufa is an important type of landscape in karst regions.In recent years,the loss of landscape diversity due to tufa dissolution is affecting the stability of local ecosystems.Therefore,determining the factors and their mechanisms involved in tufa dissolution is important for preserving regional landscape diversity and local ecosystem stability.In this study,we selected four tufa sites with different degrees of dissolution(undissolved tufa,lightly dissolved tufa,moderately dissolved tufa,and heavily dissolved tufa)in Xiangzhigou karst region of Guizhou Province as the study objects.We explored the effects of natural plant colonization on tufa dissolution using changes inαandβdiversity indices,soil physicochemical indicators,tufa components,and tufa substrate.The results indicated that the Shannon-wiener index,Simpson index and Patrick richness index gradually increased with tufa's increasing degree of dissolution.Additionally,the dissolution degree exhibited a significantly negative correlation with the species diversity(p<0.05).Natural vegetation colonization is the primary cause of changes in the proportion of tufa components and changes in the physicochemical properties of overlying tufa soils.The proportion of CaO components decreased significantly,and the proportion of loss on ignition components increased significantly.Soil organic carbon,pH,total nitrogen,available nitrogen,total phosphorus,available phosphorus,total potassium,available potassium,β-glucosidase,and urease gradually increased with deeper tufa dissolution and were negatively correlated with the degree of dissolution(p<0.05).It indicates that tufa is a process of dissolution into the soil and gradual improvement of the physicochemical properties of the overlying soil.Furthermore,scanning electron micrographs revealed the transition from dense to fragmented tufa structure under the influence of plants.In conclusion,this study found that improving plant diversity exacerbated tufa dissolution.Our findings provide a theoretical reference for the preventing and controlling of tufa dissolution in karst.
基金jointly funded by the guangxi Science and Technology Base and Talent Project(AD23026104)the Key Research and Development Program Project in Guangxi(AB23026121)。
文摘Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.
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.
文摘Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of dolines.In this research,doline susceptibility map was prepared in Saldaran mountain by generalized linear model(GLM)using 14 affecting parameters extracted from satellite images,digital elevation model,and geology map.Only 8 parameters have been inputted to the model which had correlation with dolines.In this regards,306 dolines were identified by the photogrammetric Unmanned Aerial Vehicles(UAV)method in 600 hectares of Salderan lands and then,these data were divided into the training(70%)and testing(30%)data for modelling.The results of DSM modeling showed that classified probability of doline occurrences in the Saldaran mountain were as follow:16.5%of the area high to very high,72%in the class of low to very low,and 5%in the moderate class.Also,locally,in Saldaran mountain,the Pirghar aquifer has the highest potential for the doline development,followed by Bagh Rostam and Sarab aquifers.Also,the precipitation,digital elevation model,Topographic Position Index,drainage density,slope,TRASP(transformed the circular aspect to a radiation index),Snow-Covered Days and vegetation cover index are of highest importance in the DSM modeling,respectively.Accurate evaluation of the model using the Receiver Operating Characteristics(ROC)curve represents a very good accuracy(AUC=0.953)of the DSM model.
基金supported by the Natural Science Foundation of Henan Province(242300421246,222300420007,232300421134)the National Natural Science Foundation of China(52004082,52174073,52274079,42402255)+4 种基金the Science and Technology Project of Henan Province(232102321098)Zhongyuan Science and Technology Innovation Leading Talent Program(244200510005)the Program for Science&Technology Innovation Talents in Universities of Henan Province(24HASTIT021)the Program for the Scientific and Technological Innovation Team in Universities of Henan Province(23IRTSTHN005)the National Postdoctoral Researchers Program Foundation of China(GZC20230709)。
文摘Karst collapse columns typically appear unpredictably and without a uniform spatial arrangement,posing challenges for mining operations and water inrush risk assessment.As major structural pathways for mine water inrush,they are responsible for some of the most frequent and severe water-related disasters in coal mining.Understanding the mechanisms of water inrush in these collapse columns is therefore essential for effective disaster prevention and control,making it a key research priority.Additionally,investigating the developmental characteristics of collapse columns is crucial for analyzing seepage instability mechanisms.In such a context,this paper provides a comprehensive review of four critical aspects:(1)The development characteristics and hydrogeological properties of collapse columns;(2)Fluid-solid coupling mechanisms under mining-induced stress;(3)Non-Darcy seepage behavior in fractured rock masses;(4)Flow regime transitions and mass variation effects.Key findings highlight the role of flow-solid coupling in governing the seepage mechanisms of fractured rock masses within karst collapse columns.By synthesizing numerous studies on flow pattern transitions,this paper outlines the complete seepage process-from groundwater movement within the aquifer to its migration through the collapse column and eventual inflow into mine roadways or working faces-along with the associated transformations in flow patterns.Furthermore,the seepage characteristics and water inrush behaviors influenced by particle migration are examined through both experimental and numerical simulation approaches.
