Deep Underground Science and Engineering(DUSE)is a new international journal(Online ISSN:2770-1328;Print ISSN:2097-0668)launched by China University of Mining and Technology.The Journal is managed by a renowned intern...Deep Underground Science and Engineering(DUSE)is a new international journal(Online ISSN:2770-1328;Print ISSN:2097-0668)launched by China University of Mining and Technology.The Journal is managed by a renowned international publisher John Wiley&Sons Australia,Ltd.and published quarterly in English.The Journal is devoted to building a mainstream academic exchange platform,focusing on forefront research and striving to become a world class scientifi c and technological journal.展开更多
Conventionally,foundations have been classified as shallow or deep in routine civil engineering practice.However,due to recent developments,two other approaches,semi-deep and ground modification foundations,are now av...Conventionally,foundations have been classified as shallow or deep in routine civil engineering practice.However,due to recent developments,two other approaches,semi-deep and ground modification foundations,are now available,complicating foundation categorization.Accordingly,a new concept for foundation categorization is introduced in this paper based on insights into the theory of structure analysis.Based on the form aspect,foundation systems can be categorized as one-dimensional(linear),two-dimensional(planar),and threedimensional(volumetric).Based on the load transfer aspect,foundations can also be categorized as vector-acting(piles),section or surface-acting(rafts and shells),and block-acting(piled rafts).As a step toward implementing this new categorization scheme,a database of 22 cases has been compiled,symbolizing novel introduced foundation systems.This compilation involves structures such as offshore jackets,high-rise buildings,towers and storages,and diverse geomaterials.Among them,a few have been selected for detailed evaluation,emphasizing influential factors in foundation selection,comprising superstructure,subsoil condition,foundation system,circumferential conditions,and supplementary considerations,that is,constructional and sustainability-based issues.Lessons learned from experience and these knowledge-based cases have described for foundation selection and implementation.Geotechnical and practical aspects with critical components have been realized as major performance assessment and comparison factors.Foundation systems have been compared and ranked using the improved analytic hierarchy process approach.Finally,four categories of buildings,from low-rise to towers and four prevailing levels of soil strength,from soft to very hard,have been considered to propose a perspective for building substructure implementation,adapted via relevant cases.Overall,the introduced categorization is recognized as an efficient algorithm for the experimentation of appropriate foundations for specific structures and subsoil conditions.展开更多
China has achieved a major engineering milestone in the construction of the Beishan Underground Research Laboratory(URL)for geological disposal of high-level radioactive waste(HLW).On December 26,2025,the project team...China has achieved a major engineering milestone in the construction of the Beishan Underground Research Laboratory(URL)for geological disposal of high-level radioactive waste(HLW).On December 26,2025,the project team successfully completed the excavation of the world's first deep,continuous small-radius,steep spiral ramp by a tunnel boring machine(TBM)named Beishan No.1,which marked the completion of the underground main structure of Beishan URL.展开更多
Nitrate pollution is a severe threat to the fragile ecosystems in karst regions.However,our knowledge of the sources and transformations of nitrate in karst cave groundwater is still limited.This study aimed to invest...Nitrate pollution is a severe threat to the fragile ecosystems in karst regions.However,our knowledge of the sources and transformations of nitrate in karst cave groundwater is still limited.This study aimed to investigate the temporal and spatial patterns of nitrate dynamics in the underground water of karst caves located on the south bank of the Qingjiang River in central China,through a comprehensive application of multiple approaches,such as hydrochemistry,nitrogen and oxygen isotope compositions of nitrate,and a Bayesian isotope mixing model(SIMMR).During the sampling period(from December 2018 to December 2019),the nitrate concentration did not show an apparent temporal variation;meanwhile,no water samples in this study had a nitrate concentration higher than the limit for drinking water,but the nitrate concentration in karst underground rivers is significantly higher than that in surface water.The results of the comprehensive analyses revealed that the predominant nitrate sources included nitrification in soil and chemical fertilizer,which had mean percentages of 43%and 32%,respectively.The source contribution varied in the outlet water among different caves.The soil-derived nitrate in the underground water from the Shizi Cave accounted for the highest proportion(49%),while chemical-fertilizer-derived nitrate in the underground water from the Mishui Cave accounted for the highest proportion(36%).The dualisotope signatures of nitrate supported a major influence on nitrogen dynamics in the cave underground from nitrification.These findings suggest that nitrate carried by underground rivers in karst caves should be alerted when making the nitrate balance in rivers flowing through karst areas.展开更多
The aerosolization and diffusion of radioactive materials caused by chemical explosions represent a typical nuclear accident scenario that poses severe radioactive hazards to human health and the environment.This stud...The aerosolization and diffusion of radioactive materials caused by chemical explosions represent a typical nuclear accident scenario that poses severe radioactive hazards to human health and the environment.This study examines the diffusion of plutonium aerosol generated by a chemical explosion within a typical representative underground facility.The state of explosion products following a single-point detonation of explosives was simulated.Subsequently,a numerical simulation of plutonium aerosol diffusion using the discrete phase model(DPM)was conducted based on the outcomes of the chemical explosion simulation.The simulation results indicate that plutonium aerosols diffuse throughout underground facilities after a chemical explosion;small particle size aerosols primarily accumulate in the upper part of the room after the accident;the concentrations of plutonium aerosol in the room and tunnel are significantly higher than those in the other areas;and the temporal variations in aerosol concentration in each area were quantified.Based on the particle concentration distribution and the effective dose computation approach,the study computes the internal irradiation dose received by personnel in seven areas over various time periods post-accident.Recommendations for emergency decision-making were derived from these calculations.These findings provide important theoretical insight and practical engineering application value for understanding the diffusion of radioactive aerosol in confined spaces following chemical explosions and for evaluating personnel radiation dose.展开更多
Underground engineering projects such as deep tunnel excavation often encounter rockburst disasters accompanied by numerous microseismic events.Rapid interpretation of microseismic signals is crucial for the timely id...Underground engineering projects such as deep tunnel excavation often encounter rockburst disasters accompanied by numerous microseismic events.Rapid interpretation of microseismic signals is crucial for the timely identification of rockbursts.However,conventional processing encompasses multi-step workflows,including classification,denoising,picking,locating,and computational analysis,coupled with manual intervention,which collectively compromise the reliability of early warnings.To address these challenges,this study innovatively proposes the“microseismic stethoscope"-a multi-task machine learning and deep learning model designed for the automated processing of massive microseismic signals.This model efficiently extracts three key parameters that are necessary for recognizing rockburst disasters:rupture location,microseismic energy,and moment magnitude.Specifically,the model extracts raw waveform features from three dedicated sub-networks:a classifier for source zone classification,and two regressors for microseismic energy and moment magnitude estimation.This model demonstrates superior efficiency compared to traditional processing and semi-automated processing,reducing per-event processing time from 0.71 s to 0.49 s to merely 0.036 s.It concurrently achieves 98%accuracy in source zone classification,with microseismic energy and moment magnitude estimation errors of 0.13 and 0.05,respectively.This model has been well applied and validated in the Daxiagu Tunnel case in Sichuan,China.The application results indicate that the model is as accurate as traditional methods in determining source parameters,and thus can be used to identify potential geomechanical processes of rockburst disasters.By enhancing the signal processing reliability of microseismic events,the proposed model in this study presents a significant advancement in the identification of rockburst disasters.展开更多
Underground hydrogen storage has gained interest in recent years due to the enormous demand for clean energy.Hydrogen is more diffusive than air,with a smaller density and lower viscosity.These unique properties intro...Underground hydrogen storage has gained interest in recent years due to the enormous demand for clean energy.Hydrogen is more diffusive than air,with a smaller density and lower viscosity.These unique properties introduce distinctive hydrodynamic phenomena in hydrogen storage,one of which is fingering.Fingering could induce the fluid trapped in small clusters of pores,leading to a dramatic decrease in hydrogen saturation and a lower recovery rate.In this study,numerical simulations are performed at the microscopic scale to understand the evolution of hydrogen saturation and the impacts of injection and withdrawal cycles.Two sets of micromodels with different porosity(0.362 and 0.426)and minimum sizes of pore throats(0.362 mm and 0.181 mm)are developed in the numerical model.A parameter analysis is then conducted to understand the influence of injection velocity(in the range of 10^(-2)m/s to 10^(-5)m/s)and porous structure on the fingering pattern,followed by an image analysis to capture the evolution of the fingering pattern.Viscous fingering,capillary fingering,and crossover fingering are observed and identified under different boundary conditions.The fractal dimension,specific area,mean angle,and entropy of fingers are proposed as geometric descriptors to characterize the shape of the fingering pattern.When porosity increases from 0.362 to 0.426,the saturation of hydrogen increases by 26.2%.Narrower pore throats elevate capillary resistance,which hinders fluid invasion.These results underscore the importance of pore structures and the interaction between viscous and capillary forces for hydrogen recovery efficiency.This work illuminates the influence of the pore structures and the fluid properties on the immiscible displacement of hydrogen and can be further extended to optimize the injection strategy of hydrogen in underground hydrogen storage.展开更多
The Jinping Underground Laboratory is the deepest and largest underground laboratory in the world,with a maximum buried depth of approximately 2400 m.The objective is to study the brittle-ductile transition of marble ...The Jinping Underground Laboratory is the deepest and largest underground laboratory in the world,with a maximum buried depth of approximately 2400 m.The objective is to study the brittle-ductile transition of marble through a combination of experimental research and constitutive modeling.Triaxial compression and triaxial cyclic loading tests are initially conducted to explore the accumulation of pre-peak plastic strain and the deterioration of stiffness of the marble.Then,a specific constitutive model is developed to accurately reflect the pre-peak plastic hardening and post-peak strain softening behaviors based on the deformation and failure mechanism of the marble.The incremental constitutive relationship of the proposed model is subsequently derived in detail,and the model parameters are calibrated using data obtained from the test results.Finally,the effectiveness of the proposed model is assessed by comparing its results with the experimental results of the marble.The findings show that the proposed model accurately predicts the behavior of the marble,and its results are in good agreement with the test data.展开更多
Deep karst fractures significantly drive rock strata movement induced by mining and are one of the key factors causing slope failures.Understanding the disaster formation mechanisms of mining-induced slopes controlled...Deep karst fractures significantly drive rock strata movement induced by mining and are one of the key factors causing slope failures.Understanding the disaster formation mechanisms of mining-induced slopes controlled by deep karst fractures is crucial for geological hazard prevention and mitigation.Existing research on slope failure mechanisms under the coupled influence of deep karst fractures and underground coal mining remains limited and insufficiently developed.Consequently,this study establishes a coupled geomechanical model of mining-karst interaction for layered reverse-dip slopes in southwestern China.By integrating field investigations with discrete element simulations,this study explores the deformation characteristics and failure mechanisms of deeply fractured karst slopes subjected to underground mining,along with their impacts on slope stability.The main findings are as follows:(1)Deep rock karst fractures dominated the spatial distribution of tensile fracture zones,forming a dynamic stress arch effect above the goaf;(2)The mining process dynamically induced a three-stage destruction mode of the slope,namely,the bending effect caused by the dynamic stress arch,arch migration,and the evolution of the unlocking of the locking rocks;(3)Significant spatiotemporal variability existed between the tensile zone at the top of the slope and the shear zone on the slope surface,leading to the gradual overturning of the cantilever beam structure along the dominant structural surface.It indicates that deep rock karst fractures are the primary factor controlling the disaster of the cantilever beam structure,exacerbating the degree of rock fracture and surface subsidence induced by coal mining.This study reveals the chain disaster mechanism of layered anti-dip rock karst fracture slopes in southwestern China,namely,fracture penetration,rock stratum movement-induced failure,unlocking of key rocks,and final tensile overturning destruction,profoundly elucidating the critical role of rock dissolution fissures in mining-induced slope disasters.展开更多
The effective early warning of surrounding rock mass deformation is crucial in geotechnical engineering for ensuring the safety and stability of underground constructions.This study introduces a novel risk early warni...The effective early warning of surrounding rock mass deformation is crucial in geotechnical engineering for ensuring the safety and stability of underground constructions.This study introduces a novel risk early warning model based on multi-parameter fuzzy comprehensive evaluation,which quantitatively assesses the risk state of the surrounding rock mass.The microseismic(MS)monitoring system is set up for the underground powerhouse.The spatial and temporal distribution of MS events and the frequency characteristics of MS signals are analyzed during the top arch excavation.The early warning indices for characterizing MS spatial aggregation and frequency-energy dispersion are proposed based on the octree theory to assess the deformation of the surrounding rock mass.The risk warning model for the surrounding rock mass in underground engineering is developed through the integration of the formulated index and the frequency characteristics of MS signals.The results indicate that the multiparameter fuzzy comprehensive assessment model can achieve three-dimensional visualization of risk warnings for the surrounding rock mass.The quantitative results regarding warning time and potential deformation areas are highly consistent with the characteristics of MS precursors.These research results can provide an important reference for early warning of surrounding rock mass risk in similar underground projects.展开更多
Coal mine underground reservoirs help address the severe water imbalance in ecologically fragile mining regions of western China,but evaluating their storage capacity remains challenging due to the coupled effects of ...Coal mine underground reservoirs help address the severe water imbalance in ecologically fragile mining regions of western China,but evaluating their storage capacity remains challenging due to the coupled effects of gangue deformation,saturation,and goaf geometry.This study investigates the deformation and void evolution of fragmented gangue with varying lithologies,particle sizes,and water contents through an independent-developed testing system and theoretical model.A planar micro-unit model and a three-dimensional spatial structure model are proposed to quantify the storage coefficient and total reservoir capacity of underground water storage structures.These models incorporate the effects of stratified lithologies,saturation-induced softening,and spatially distributed stress conditions.The methodology is applied to the underground reservoir in Chahasu coal mine,and the results show that under increasing stress,storage coefficients decline exponentially,with pronounced differences between single-and double-lithology structures.The storage coefficient in the spatial model demonstrate greater resilience to stress concentration compared to planar models,and further analysis identifies critical thresholds in roof fracture distances and stress-recovery times affecting long-term storage performance.This research provides a comprehensive framework for evaluating underground reservoir storage potential,offering theoretical support and engineering guidance for the sustainable utilization of mine water.展开更多
The coal dynamic characteristic stress identification under dynamic load is important for guiding underground mineral mining and predicting underground dynamic disasters.In this article,the dynamic compression test of...The coal dynamic characteristic stress identification under dynamic load is important for guiding underground mineral mining and predicting underground dynamic disasters.In this article,the dynamic compression test of anthracite under five strain rates is carried out,the evolution law of three kinds of crack characteristic stress is analyzed,and a prediction model of the crack characteristic stress threshold considering the strain rate effect is established.Then,the rationality of crack characteristic stress under dynamic loading is discussed from the damage evolution standpoint,and the crack extension response mechanism during dynamic compression of anthracite is discussed.The result shows that the crack characteristic stress threshold is significantly influenced by the strain rate.The three characteristic stress thresholds are positively correlated with the strain rate,but the ratios to the crest stress gradually decrease.The increase in the strain rate strongly contributes to the crack extension behavior of anthracite.In the crack unstable extension phase,because of the increase of the strain rate,anthracite shows more energy dissipation under the same deformation in association with the stress concentration effect and the dynamic strength enhancement effect.The crack propagation rate is increased,the crack propagation path of the section is more complex,and more severe damage occurs before the dynamic failure of anthracite,which leads to even more severe damage.展开更多
Discontinuities in rock masses critically impact the stability and safety of underground engineering.Mainstream discontinuities identificationmethods,which rely on normal vector estimation and clustering algorithms,su...Discontinuities in rock masses critically impact the stability and safety of underground engineering.Mainstream discontinuities identificationmethods,which rely on normal vector estimation and clustering algorithms,suffer from accuracy degradation,omission of critical discontinuities when orientation density is unevenly distributed,and need manual intervention.To overcome these limitations,this paper introduces a novel discontinuities identificationmethod based on geometric feature analysis of rock mass.By analyzing spatial distribution variability of point cloud and integrating an adaptive region growing algorithm,the method accurately detects independent discontinuities under complex geological conditions.Given that rock mass orientations typically follow a Fisher distribution,an adaptive hierarchical clustering algorithm based on statistical analysis is employed to automatically determine the optimal number of structural sets,eliminating the need for preset clusters or thresholds inherent in traditional methods.The proposed approach effectively handles diverse rock mass shapes and sizes,leveraging both local and global geometric features to minimize noise interference.Experimental validation on three real-world rock mass models,alongside comparisons with three conventional directional clustering algorithms,demonstrates superior accuracy and robustness in identifying optimal discontinuity sets.The proposed method offers a reliable and efficienttool for discontinuities detection and grouping in underground engineering,significantlyenhancing design and construction outcomes.展开更多
0 INTRODUCTION Throughout human history,three major energy transitions have occurred:from burning wood in primitive times to using coal in 18th Century,then to oil and gas in 20th Century,and to the renewable energy r...0 INTRODUCTION Throughout human history,three major energy transitions have occurred:from burning wood in primitive times to using coal in 18th Century,then to oil and gas in 20th Century,and to the renewable energy revolution in the 21st Century(Zou et al.,2023).The three transitions have three characteristics in common:shifted from nonrenewable to renewable energy,from“resource-centric”to a“technology-centric”,and from“high-carbon fossil”to“net-zero”.展开更多
To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,insp...To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,inspired by the concepts of the toughness seismic resistance and rocking design.Although many experimental and numerical studies have focused on underground structures,research on the behavior of truncated columns remains limited.This paper develops threedimensional(3D)finite element(FE)models for various columns,including cast-in-place column(CIPC)and prestressed tendon truncated column(PTTC),to evaluate the effects of three parameters,including axial compression ratio(ACR),initial tendon stress,and the effect of hole diameter on mechanical performance—specifically deformation capacity,strength,residual deformation and gap width.The results indicate that the deformability and self-centering ability of the prestressed tendon truncated column is obviously superior to the cast-in-place column,but its strength was comparatively lower.The axial compression ratio has obvious effects on seismic performance,especially deformation and residual deformation,while initial tendon stress and hole diameter influence performance only in the case of a small axial compression ratio.This study systematically identifies the influence of various factors on seismic performance.Additionally,this study proposes a method to evaluate the self-centering capability of structures and establishes an empirical relationship between maximum recoverable deformation and the axial compression ratio.The developed numerical model can serve as a tool for future studies to predict the seismic responses of overall subway stations that feature truncated columns.展开更多
Scientific and technological advancements are rapidly transforming underground engineering,shifting from labor-intensive,time-consuming methods to automated,real-time systems.This timely and comprehensive review cover...Scientific and technological advancements are rapidly transforming underground engineering,shifting from labor-intensive,time-consuming methods to automated,real-time systems.This timely and comprehensive review covers in-situ testing,intelligent monitoring,and geophysical testing methods,highlighting fundamental principles,testing apparatuses,data processing techniques,and engineering applications.The state-of-the-art summary emphasizes not only cutting-edge innovations for complex and harsh environments but also the transformative role of artificial intelligence and machine learning in data interpretations.The integration of big data and advanced algorithms is particularly impactful,enabling the identification,prediction,and mitigation of potential risks in underground projects.Key aspects of the discussion include detection capabilities,method integration,and data convergence of intelligent technologies to drive enhanced safety,operational efficiency,and predictive reliability.The review also examines future trends in intelligent technologies,emphasizing unified platforms that combine multiple methods,real-time data,and predictive analytics.These advancements are shaping the evolution of underground construction and maintenance,aiming for risk-free,high-efficiency underground engineering.展开更多
This study investigates the mechanical response of an underground cavern subjected to cyclic high gas pressure,aiming to establish a theoretical foundation for the design of lined rock caverns(LRCs)for energy storage ...This study investigates the mechanical response of an underground cavern subjected to cyclic high gas pressure,aiming to establish a theoretical foundation for the design of lined rock caverns(LRCs)for energy storage with high internal pressure,e.g.compressed air energy storage(CAES)underground caverns or hydrogen storage caverns.Initially,the stress paths of the surrounding rock during the excavation,pressurization,and depressurization processes are delineated.Analytical expressions for the stress and deformation of the surrounding rock are derived based on the MohreCoulomb criterion.These expressions are then employed to evaluate the displacement of cavern walls under varying qualities of surrounding rock,the contact pressure between the steel lining and the surrounding rock subject to different gas storage pressures,the load-bearing ratio of the surrounding rock,and the impact of lining thickness on the critical gas pressure.Furthermore,the deformation paths of the surrounding rock are evaluated,along with the effects of tunnel depth and diameter on residual deformation of the surrounding rock,and the critical minimum gas pressure at which the surrounding rock and the lining do not detach.The results indicate that residual deformation of the surrounding rock occurs after depressurization under higher internal pressure for higher-quality rock masses,leading to detachment between the surrounding rock and the steel lining.The findings indicate that thicker linings correspond to higher critical minimum gas pressures.However,for lower-quality surrounding rock,thicker linings correspond to lower critical minimum gas pressures.These findings will provide invaluable insights for the design of LRCs for underground energy storage caverns.展开更多
The large-scale accumulation of industrial solid waste,including red mud and coal gangue,coupled with goafs left by under-ground mining activities,poses significant challenges to sustainable human development.In this ...The large-scale accumulation of industrial solid waste,including red mud and coal gangue,coupled with goafs left by under-ground mining activities,poses significant challenges to sustainable human development.In this study,red mud,coal gangue,and othersolid wastes were used to prepare underground backfilling materials.The utilization rate of the total solid waste reached 95%,with redmud accounting for approximately 40wt% of the total.The unconfined compressive strength,setting time,and slump tests were conduc-ted to evaluate the mechanical properties of the material.At the optimal ratio,the 7-and 28-d strengths reach 4.4 and 6.9 MPa,respect-ively.The initial and final setting times were 200 and 250 min,respectively,whereas the initial and 1-h slump exceed 250 and 210 mm,respectively.X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and scanning electron microscopy(SEM)wereemployed to explore the microstructure,phase composition,and chemical bonding within the material.Needle-like,clustered,and granu-lar hydration products were observed,and the primary crystalline structures were identified as ettringite,gmelinite,C-A-S-H,andC-S-H.In addition,a thorough environmental risk assessment was conducted,complemented by detailed economic cost and carbonemission calculations.During the creation of backfill material,hazardous elements from solid waste are immobilized through adsorption,precipitation,and incorporation into the crystal lattice.The immobilization efficiencies for Ni,Al,Cr^(6+),and As were 97.03%,94.32%,86.43%,and 84.22%,respectively,at a pH of 8.49.Moreover,the use of solid waste as a raw material results in considerable cost savingsand marked reduction in carbon emissions.This study innovatively promotes the green cycle of alumina production in the bauxite miningindustry.展开更多
Hydrogen,a genuinely clean energy,is a promising alternative to fossil fuels.Inspired by underground gas storage of methane,establishing underground hydrogen storage(UHS)in depleted oil and gas reservoirs has emerged ...Hydrogen,a genuinely clean energy,is a promising alternative to fossil fuels.Inspired by underground gas storage of methane,establishing underground hydrogen storage(UHS)in depleted oil and gas reservoirs has emerged as a significant research focus.Carbonate reservoirs,where widely-presented fractures can facilitate the high-speed injection and production of gases,are hence ideal candidates for building underground hydrogen storage facilities.During the cyclic injection and extraction processes of UHS,the formation is subjected to stress disturbances,leading to stress sensitivity.Understanding the stress sensitivity patterns of carbonate rocks is crucial for optimizing injection and production strategies.This study reconstructed three-dimensional digital models of fractured carbonate rocks from the L gas field using micro-CT scanning technology.Utilizing the finite element method,we investigated the microscopic permeability characteristics of carbonate rocks and analyzed the impact of stress loading direction and confining stress on stress sensitivity.The findings reveal that the stress loading direction significantly influences the stress sensitivity of fractured carbonate rocks.When a stress of 60 MPa is applied perpendicular to the fracture direction,the permeability reduction ratio can reach 17.32%.In contrast,when the same stress is applied parallel to the fracture direction,the permeability reduction ratio is only 4.82%.Furthermore,a simulation of UHS with cyclic injection and production of H2 in the target block was conducted.When both permeability and porosity stress sensitivity were considered,the working gas volume for UHS decreased by only 3.4%,demonstrating that fractured carbonate reservoirs are feasible candidates for constructing underground hydrogen storage.展开更多
China has a long history of coal mining,among which open-pit coal mines have a large number of small coal mine goafs underground.The distribution,shape,structure and other characteristics of goafs are isolated and dis...China has a long history of coal mining,among which open-pit coal mines have a large number of small coal mine goafs underground.The distribution,shape,structure and other characteristics of goafs are isolated and discontinuous,and there is no definite geological law to follow,which seriously threatens the safety of coal mine production and personnel life.Conventional ground geophysical methods have low accuracy in detecting goaf areas affected by mechanical interference from open-pit mines,especially for waterless goaf areas,which cannot be detected by existing methods.This article proposes the use of high-frequency electromagnetic waves for goaf detection.The feasibility of using drilling radar to detect goaf was theoretically analyzed,and a goaf detection model was established.The response characteristics of different fillers in the goaf under different frequencies of high-frequency electromagnetic waves were simulated and analyzed.In a certain open-pit mine in Inner Mongolia,100MHz high-frequency electromagnetic waves were used to detect the goaf through directional drilling on the ground.After detection,excavation verification was carried out,and the location of one goaf detected was verified.The results of engineering practice show that the application of high-frequency electromagnetic waves in goaf detection expands the detection radius of boreholes,has the advantages of high efficiency and accuracy,and has important theoretical and practical significance.展开更多
文摘Deep Underground Science and Engineering(DUSE)is a new international journal(Online ISSN:2770-1328;Print ISSN:2097-0668)launched by China University of Mining and Technology.The Journal is managed by a renowned international publisher John Wiley&Sons Australia,Ltd.and published quarterly in English.The Journal is devoted to building a mainstream academic exchange platform,focusing on forefront research and striving to become a world class scientifi c and technological journal.
文摘Conventionally,foundations have been classified as shallow or deep in routine civil engineering practice.However,due to recent developments,two other approaches,semi-deep and ground modification foundations,are now available,complicating foundation categorization.Accordingly,a new concept for foundation categorization is introduced in this paper based on insights into the theory of structure analysis.Based on the form aspect,foundation systems can be categorized as one-dimensional(linear),two-dimensional(planar),and threedimensional(volumetric).Based on the load transfer aspect,foundations can also be categorized as vector-acting(piles),section or surface-acting(rafts and shells),and block-acting(piled rafts).As a step toward implementing this new categorization scheme,a database of 22 cases has been compiled,symbolizing novel introduced foundation systems.This compilation involves structures such as offshore jackets,high-rise buildings,towers and storages,and diverse geomaterials.Among them,a few have been selected for detailed evaluation,emphasizing influential factors in foundation selection,comprising superstructure,subsoil condition,foundation system,circumferential conditions,and supplementary considerations,that is,constructional and sustainability-based issues.Lessons learned from experience and these knowledge-based cases have described for foundation selection and implementation.Geotechnical and practical aspects with critical components have been realized as major performance assessment and comparison factors.Foundation systems have been compared and ranked using the improved analytic hierarchy process approach.Finally,four categories of buildings,from low-rise to towers and four prevailing levels of soil strength,from soft to very hard,have been considered to propose a perspective for building substructure implementation,adapted via relevant cases.Overall,the introduced categorization is recognized as an efficient algorithm for the experimentation of appropriate foundations for specific structures and subsoil conditions.
文摘China has achieved a major engineering milestone in the construction of the Beishan Underground Research Laboratory(URL)for geological disposal of high-level radioactive waste(HLW).On December 26,2025,the project team successfully completed the excavation of the world's first deep,continuous small-radius,steep spiral ramp by a tunnel boring machine(TBM)named Beishan No.1,which marked the completion of the underground main structure of Beishan URL.
基金supported by the National Natural Science Foundation of China(Nos.42372355,42530706)。
文摘Nitrate pollution is a severe threat to the fragile ecosystems in karst regions.However,our knowledge of the sources and transformations of nitrate in karst cave groundwater is still limited.This study aimed to investigate the temporal and spatial patterns of nitrate dynamics in the underground water of karst caves located on the south bank of the Qingjiang River in central China,through a comprehensive application of multiple approaches,such as hydrochemistry,nitrogen and oxygen isotope compositions of nitrate,and a Bayesian isotope mixing model(SIMMR).During the sampling period(from December 2018 to December 2019),the nitrate concentration did not show an apparent temporal variation;meanwhile,no water samples in this study had a nitrate concentration higher than the limit for drinking water,but the nitrate concentration in karst underground rivers is significantly higher than that in surface water.The results of the comprehensive analyses revealed that the predominant nitrate sources included nitrification in soil and chemical fertilizer,which had mean percentages of 43%and 32%,respectively.The source contribution varied in the outlet water among different caves.The soil-derived nitrate in the underground water from the Shizi Cave accounted for the highest proportion(49%),while chemical-fertilizer-derived nitrate in the underground water from the Mishui Cave accounted for the highest proportion(36%).The dualisotope signatures of nitrate supported a major influence on nitrogen dynamics in the cave underground from nitrification.These findings suggest that nitrate carried by underground rivers in karst caves should be alerted when making the nitrate balance in rivers flowing through karst areas.
文摘The aerosolization and diffusion of radioactive materials caused by chemical explosions represent a typical nuclear accident scenario that poses severe radioactive hazards to human health and the environment.This study examines the diffusion of plutonium aerosol generated by a chemical explosion within a typical representative underground facility.The state of explosion products following a single-point detonation of explosives was simulated.Subsequently,a numerical simulation of plutonium aerosol diffusion using the discrete phase model(DPM)was conducted based on the outcomes of the chemical explosion simulation.The simulation results indicate that plutonium aerosols diffuse throughout underground facilities after a chemical explosion;small particle size aerosols primarily accumulate in the upper part of the room after the accident;the concentrations of plutonium aerosol in the room and tunnel are significantly higher than those in the other areas;and the temporal variations in aerosol concentration in each area were quantified.Based on the particle concentration distribution and the effective dose computation approach,the study computes the internal irradiation dose received by personnel in seven areas over various time periods post-accident.Recommendations for emergency decision-making were derived from these calculations.These findings provide important theoretical insight and practical engineering application value for understanding the diffusion of radioactive aerosol in confined spaces following chemical explosions and for evaluating personnel radiation dose.
基金supported by the National Natural Science Foundation of China(Grant Nos.42130719 and 42177173)the Doctoral Direct Train Project of Chongqing Natural Science Foundation(Grant No.CSTB2023NSCQ-BSX0029).
文摘Underground engineering projects such as deep tunnel excavation often encounter rockburst disasters accompanied by numerous microseismic events.Rapid interpretation of microseismic signals is crucial for the timely identification of rockbursts.However,conventional processing encompasses multi-step workflows,including classification,denoising,picking,locating,and computational analysis,coupled with manual intervention,which collectively compromise the reliability of early warnings.To address these challenges,this study innovatively proposes the“microseismic stethoscope"-a multi-task machine learning and deep learning model designed for the automated processing of massive microseismic signals.This model efficiently extracts three key parameters that are necessary for recognizing rockburst disasters:rupture location,microseismic energy,and moment magnitude.Specifically,the model extracts raw waveform features from three dedicated sub-networks:a classifier for source zone classification,and two regressors for microseismic energy and moment magnitude estimation.This model demonstrates superior efficiency compared to traditional processing and semi-automated processing,reducing per-event processing time from 0.71 s to 0.49 s to merely 0.036 s.It concurrently achieves 98%accuracy in source zone classification,with microseismic energy and moment magnitude estimation errors of 0.13 and 0.05,respectively.This model has been well applied and validated in the Daxiagu Tunnel case in Sichuan,China.The application results indicate that the model is as accurate as traditional methods in determining source parameters,and thus can be used to identify potential geomechanical processes of rockburst disasters.By enhancing the signal processing reliability of microseismic events,the proposed model in this study presents a significant advancement in the identification of rockburst disasters.
基金supported by the National Key Research and Development Project(Grant No.2023YFE0110900)the National Natural Science Foundation of China(Grant Nos.42320104003,42477168).
文摘Underground hydrogen storage has gained interest in recent years due to the enormous demand for clean energy.Hydrogen is more diffusive than air,with a smaller density and lower viscosity.These unique properties introduce distinctive hydrodynamic phenomena in hydrogen storage,one of which is fingering.Fingering could induce the fluid trapped in small clusters of pores,leading to a dramatic decrease in hydrogen saturation and a lower recovery rate.In this study,numerical simulations are performed at the microscopic scale to understand the evolution of hydrogen saturation and the impacts of injection and withdrawal cycles.Two sets of micromodels with different porosity(0.362 and 0.426)and minimum sizes of pore throats(0.362 mm and 0.181 mm)are developed in the numerical model.A parameter analysis is then conducted to understand the influence of injection velocity(in the range of 10^(-2)m/s to 10^(-5)m/s)and porous structure on the fingering pattern,followed by an image analysis to capture the evolution of the fingering pattern.Viscous fingering,capillary fingering,and crossover fingering are observed and identified under different boundary conditions.The fractal dimension,specific area,mean angle,and entropy of fingers are proposed as geometric descriptors to characterize the shape of the fingering pattern.When porosity increases from 0.362 to 0.426,the saturation of hydrogen increases by 26.2%.Narrower pore throats elevate capillary resistance,which hinders fluid invasion.These results underscore the importance of pore structures and the interaction between viscous and capillary forces for hydrogen recovery efficiency.This work illuminates the influence of the pore structures and the fluid properties on the immiscible displacement of hydrogen and can be further extended to optimize the injection strategy of hydrogen in underground hydrogen storage.
基金China Power Construction Group research project,Grant/Award Number:DJ-HXGG-2023-16National Natural Science Foundation of China-Yalong River Joint Fund Key Project,Grant/Award Number:U1965204+1 种基金National Natural Science Foundation of China,Grant/Award Number:52109143Open Research Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin(China Institute of Water Resources and Hydropower Research),Grant/Award Number:IWHR-SKL-KF202305。
文摘The Jinping Underground Laboratory is the deepest and largest underground laboratory in the world,with a maximum buried depth of approximately 2400 m.The objective is to study the brittle-ductile transition of marble through a combination of experimental research and constitutive modeling.Triaxial compression and triaxial cyclic loading tests are initially conducted to explore the accumulation of pre-peak plastic strain and the deterioration of stiffness of the marble.Then,a specific constitutive model is developed to accurately reflect the pre-peak plastic hardening and post-peak strain softening behaviors based on the deformation and failure mechanism of the marble.The incremental constitutive relationship of the proposed model is subsequently derived in detail,and the model parameters are calibrated using data obtained from the test results.Finally,the effectiveness of the proposed model is assessed by comparing its results with the experimental results of the marble.The findings show that the proposed model accurately predicts the behavior of the marble,and its results are in good agreement with the test data.
基金financially supported by the Guizhou Provincial Basic Research Program(Natural Science)(ZD[2025]007)the Guizhou Provincial Program on Commercialization of Scientific and Technological Achievements(N0.QKHCG-LH2024-ZD025)the National Natural Science Foundation of China(Grant No.42067046)。
文摘Deep karst fractures significantly drive rock strata movement induced by mining and are one of the key factors causing slope failures.Understanding the disaster formation mechanisms of mining-induced slopes controlled by deep karst fractures is crucial for geological hazard prevention and mitigation.Existing research on slope failure mechanisms under the coupled influence of deep karst fractures and underground coal mining remains limited and insufficiently developed.Consequently,this study establishes a coupled geomechanical model of mining-karst interaction for layered reverse-dip slopes in southwestern China.By integrating field investigations with discrete element simulations,this study explores the deformation characteristics and failure mechanisms of deeply fractured karst slopes subjected to underground mining,along with their impacts on slope stability.The main findings are as follows:(1)Deep rock karst fractures dominated the spatial distribution of tensile fracture zones,forming a dynamic stress arch effect above the goaf;(2)The mining process dynamically induced a three-stage destruction mode of the slope,namely,the bending effect caused by the dynamic stress arch,arch migration,and the evolution of the unlocking of the locking rocks;(3)Significant spatiotemporal variability existed between the tensile zone at the top of the slope and the shear zone on the slope surface,leading to the gradual overturning of the cantilever beam structure along the dominant structural surface.It indicates that deep rock karst fractures are the primary factor controlling the disaster of the cantilever beam structure,exacerbating the degree of rock fracture and surface subsidence induced by coal mining.This study reveals the chain disaster mechanism of layered anti-dip rock karst fracture slopes in southwestern China,namely,fracture penetration,rock stratum movement-induced failure,unlocking of key rocks,and final tensile overturning destruction,profoundly elucidating the critical role of rock dissolution fissures in mining-induced slope disasters.
基金support from the Sichuan Science and Technology Program(Grant No.2023NSFSC0812).
文摘The effective early warning of surrounding rock mass deformation is crucial in geotechnical engineering for ensuring the safety and stability of underground constructions.This study introduces a novel risk early warning model based on multi-parameter fuzzy comprehensive evaluation,which quantitatively assesses the risk state of the surrounding rock mass.The microseismic(MS)monitoring system is set up for the underground powerhouse.The spatial and temporal distribution of MS events and the frequency characteristics of MS signals are analyzed during the top arch excavation.The early warning indices for characterizing MS spatial aggregation and frequency-energy dispersion are proposed based on the octree theory to assess the deformation of the surrounding rock mass.The risk warning model for the surrounding rock mass in underground engineering is developed through the integration of the formulated index and the frequency characteristics of MS signals.The results indicate that the multiparameter fuzzy comprehensive assessment model can achieve three-dimensional visualization of risk warnings for the surrounding rock mass.The quantitative results regarding warning time and potential deformation areas are highly consistent with the characteristics of MS precursors.These research results can provide an important reference for early warning of surrounding rock mass risk in similar underground projects.
基金supported by the National Natural Science Foundation of China(Nos.52404153,52504157 and 52504156)the Natural Science Foundation of Jiangsu Province(No.BK20241649).
文摘Coal mine underground reservoirs help address the severe water imbalance in ecologically fragile mining regions of western China,but evaluating their storage capacity remains challenging due to the coupled effects of gangue deformation,saturation,and goaf geometry.This study investigates the deformation and void evolution of fragmented gangue with varying lithologies,particle sizes,and water contents through an independent-developed testing system and theoretical model.A planar micro-unit model and a three-dimensional spatial structure model are proposed to quantify the storage coefficient and total reservoir capacity of underground water storage structures.These models incorporate the effects of stratified lithologies,saturation-induced softening,and spatially distributed stress conditions.The methodology is applied to the underground reservoir in Chahasu coal mine,and the results show that under increasing stress,storage coefficients decline exponentially,with pronounced differences between single-and double-lithology structures.The storage coefficient in the spatial model demonstrate greater resilience to stress concentration compared to planar models,and further analysis identifies critical thresholds in roof fracture distances and stress-recovery times affecting long-term storage performance.This research provides a comprehensive framework for evaluating underground reservoir storage potential,offering theoretical support and engineering guidance for the sustainable utilization of mine water.
基金National Natural Science Foundation of China,Grant/Award Numbers:12072363,12372373,51934007,52104234,52174091。
文摘The coal dynamic characteristic stress identification under dynamic load is important for guiding underground mineral mining and predicting underground dynamic disasters.In this article,the dynamic compression test of anthracite under five strain rates is carried out,the evolution law of three kinds of crack characteristic stress is analyzed,and a prediction model of the crack characteristic stress threshold considering the strain rate effect is established.Then,the rationality of crack characteristic stress under dynamic loading is discussed from the damage evolution standpoint,and the crack extension response mechanism during dynamic compression of anthracite is discussed.The result shows that the crack characteristic stress threshold is significantly influenced by the strain rate.The three characteristic stress thresholds are positively correlated with the strain rate,but the ratios to the crest stress gradually decrease.The increase in the strain rate strongly contributes to the crack extension behavior of anthracite.In the crack unstable extension phase,because of the increase of the strain rate,anthracite shows more energy dissipation under the same deformation in association with the stress concentration effect and the dynamic strength enhancement effect.The crack propagation rate is increased,the crack propagation path of the section is more complex,and more severe damage occurs before the dynamic failure of anthracite,which leads to even more severe damage.
基金the National Key Research and Development Program of China(Grant No.2023YFC3009400).
文摘Discontinuities in rock masses critically impact the stability and safety of underground engineering.Mainstream discontinuities identificationmethods,which rely on normal vector estimation and clustering algorithms,suffer from accuracy degradation,omission of critical discontinuities when orientation density is unevenly distributed,and need manual intervention.To overcome these limitations,this paper introduces a novel discontinuities identificationmethod based on geometric feature analysis of rock mass.By analyzing spatial distribution variability of point cloud and integrating an adaptive region growing algorithm,the method accurately detects independent discontinuities under complex geological conditions.Given that rock mass orientations typically follow a Fisher distribution,an adaptive hierarchical clustering algorithm based on statistical analysis is employed to automatically determine the optimal number of structural sets,eliminating the need for preset clusters or thresholds inherent in traditional methods.The proposed approach effectively handles diverse rock mass shapes and sizes,leveraging both local and global geometric features to minimize noise interference.Experimental validation on three real-world rock mass models,alongside comparisons with three conventional directional clustering algorithms,demonstrates superior accuracy and robustness in identifying optimal discontinuity sets.The proposed method offers a reliable and efficienttool for discontinuities detection and grouping in underground engineering,significantlyenhancing design and construction outcomes.
基金supported by the National Natural Science Foundation of China“Quantitative characterization of lacustrine shale oil mobility based on nano-scale oil-rock interactions”(No.42172180)Science and Technology Research Project for the China National Petroleum Corporation“Source-reservoir characteristics and sweet spot evaluation for terrestrial shale oil in China”(No.2021DJ1802)。
文摘0 INTRODUCTION Throughout human history,three major energy transitions have occurred:from burning wood in primitive times to using coal in 18th Century,then to oil and gas in 20th Century,and to the renewable energy revolution in the 21st Century(Zou et al.,2023).The three transitions have three characteristics in common:shifted from nonrenewable to renewable energy,from“resource-centric”to a“technology-centric”,and from“high-carbon fossil”to“net-zero”.
基金National Natural Science Foundation of China under Grant Nos.52478488 and 51908013the National Key Basic Research and Development Program of China under Grant No.2018YFC1504305。
文摘To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,inspired by the concepts of the toughness seismic resistance and rocking design.Although many experimental and numerical studies have focused on underground structures,research on the behavior of truncated columns remains limited.This paper develops threedimensional(3D)finite element(FE)models for various columns,including cast-in-place column(CIPC)and prestressed tendon truncated column(PTTC),to evaluate the effects of three parameters,including axial compression ratio(ACR),initial tendon stress,and the effect of hole diameter on mechanical performance—specifically deformation capacity,strength,residual deformation and gap width.The results indicate that the deformability and self-centering ability of the prestressed tendon truncated column is obviously superior to the cast-in-place column,but its strength was comparatively lower.The axial compression ratio has obvious effects on seismic performance,especially deformation and residual deformation,while initial tendon stress and hole diameter influence performance only in the case of a small axial compression ratio.This study systematically identifies the influence of various factors on seismic performance.Additionally,this study proposes a method to evaluate the self-centering capability of structures and establishes an empirical relationship between maximum recoverable deformation and the axial compression ratio.The developed numerical model can serve as a tool for future studies to predict the seismic responses of overall subway stations that feature truncated columns.
基金supported by Ministry of Education of Singapore,under Academic Research Fund Tier 1(Grant Number RG143/23).
文摘Scientific and technological advancements are rapidly transforming underground engineering,shifting from labor-intensive,time-consuming methods to automated,real-time systems.This timely and comprehensive review covers in-situ testing,intelligent monitoring,and geophysical testing methods,highlighting fundamental principles,testing apparatuses,data processing techniques,and engineering applications.The state-of-the-art summary emphasizes not only cutting-edge innovations for complex and harsh environments but also the transformative role of artificial intelligence and machine learning in data interpretations.The integration of big data and advanced algorithms is particularly impactful,enabling the identification,prediction,and mitigation of potential risks in underground projects.Key aspects of the discussion include detection capabilities,method integration,and data convergence of intelligent technologies to drive enhanced safety,operational efficiency,and predictive reliability.The review also examines future trends in intelligent technologies,emphasizing unified platforms that combine multiple methods,real-time data,and predictive analytics.These advancements are shaping the evolution of underground construction and maintenance,aiming for risk-free,high-efficiency underground engineering.
基金supported by the State Key Laboratory of Disaster Reduction in Civil Engineering(Grant No.SLDRCE23-02)Ningbo PublicWelfare Fund Project(Grant No.2023S100)the National Key Research and Development Program of China(Grant No.2024YFE0105800).
文摘This study investigates the mechanical response of an underground cavern subjected to cyclic high gas pressure,aiming to establish a theoretical foundation for the design of lined rock caverns(LRCs)for energy storage with high internal pressure,e.g.compressed air energy storage(CAES)underground caverns or hydrogen storage caverns.Initially,the stress paths of the surrounding rock during the excavation,pressurization,and depressurization processes are delineated.Analytical expressions for the stress and deformation of the surrounding rock are derived based on the MohreCoulomb criterion.These expressions are then employed to evaluate the displacement of cavern walls under varying qualities of surrounding rock,the contact pressure between the steel lining and the surrounding rock subject to different gas storage pressures,the load-bearing ratio of the surrounding rock,and the impact of lining thickness on the critical gas pressure.Furthermore,the deformation paths of the surrounding rock are evaluated,along with the effects of tunnel depth and diameter on residual deformation of the surrounding rock,and the critical minimum gas pressure at which the surrounding rock and the lining do not detach.The results indicate that residual deformation of the surrounding rock occurs after depressurization under higher internal pressure for higher-quality rock masses,leading to detachment between the surrounding rock and the steel lining.The findings indicate that thicker linings correspond to higher critical minimum gas pressures.However,for lower-quality surrounding rock,thicker linings correspond to lower critical minimum gas pressures.These findings will provide invaluable insights for the design of LRCs for underground energy storage caverns.
基金financially supported by the National Nature Science Foundation of China(No.U23A20557)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2022QNRC001)Fundamental Research Funds for the Central Universities,China(No.00007720)。
文摘The large-scale accumulation of industrial solid waste,including red mud and coal gangue,coupled with goafs left by under-ground mining activities,poses significant challenges to sustainable human development.In this study,red mud,coal gangue,and othersolid wastes were used to prepare underground backfilling materials.The utilization rate of the total solid waste reached 95%,with redmud accounting for approximately 40wt% of the total.The unconfined compressive strength,setting time,and slump tests were conduc-ted to evaluate the mechanical properties of the material.At the optimal ratio,the 7-and 28-d strengths reach 4.4 and 6.9 MPa,respect-ively.The initial and final setting times were 200 and 250 min,respectively,whereas the initial and 1-h slump exceed 250 and 210 mm,respectively.X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and scanning electron microscopy(SEM)wereemployed to explore the microstructure,phase composition,and chemical bonding within the material.Needle-like,clustered,and granu-lar hydration products were observed,and the primary crystalline structures were identified as ettringite,gmelinite,C-A-S-H,andC-S-H.In addition,a thorough environmental risk assessment was conducted,complemented by detailed economic cost and carbonemission calculations.During the creation of backfill material,hazardous elements from solid waste are immobilized through adsorption,precipitation,and incorporation into the crystal lattice.The immobilization efficiencies for Ni,Al,Cr^(6+),and As were 97.03%,94.32%,86.43%,and 84.22%,respectively,at a pH of 8.49.Moreover,the use of solid waste as a raw material results in considerable cost savingsand marked reduction in carbon emissions.This study innovatively promotes the green cycle of alumina production in the bauxite miningindustry.
基金National Natural Science Foundation of China,52304048Ye Tian,China Postdoctoral Science Foundation,2022M722637,Ye Tian。
文摘Hydrogen,a genuinely clean energy,is a promising alternative to fossil fuels.Inspired by underground gas storage of methane,establishing underground hydrogen storage(UHS)in depleted oil and gas reservoirs has emerged as a significant research focus.Carbonate reservoirs,where widely-presented fractures can facilitate the high-speed injection and production of gases,are hence ideal candidates for building underground hydrogen storage facilities.During the cyclic injection and extraction processes of UHS,the formation is subjected to stress disturbances,leading to stress sensitivity.Understanding the stress sensitivity patterns of carbonate rocks is crucial for optimizing injection and production strategies.This study reconstructed three-dimensional digital models of fractured carbonate rocks from the L gas field using micro-CT scanning technology.Utilizing the finite element method,we investigated the microscopic permeability characteristics of carbonate rocks and analyzed the impact of stress loading direction and confining stress on stress sensitivity.The findings reveal that the stress loading direction significantly influences the stress sensitivity of fractured carbonate rocks.When a stress of 60 MPa is applied perpendicular to the fracture direction,the permeability reduction ratio can reach 17.32%.In contrast,when the same stress is applied parallel to the fracture direction,the permeability reduction ratio is only 4.82%.Furthermore,a simulation of UHS with cyclic injection and production of H2 in the target block was conducted.When both permeability and porosity stress sensitivity were considered,the working gas volume for UHS decreased by only 3.4%,demonstrating that fractured carbonate reservoirs are feasible candidates for constructing underground hydrogen storage.
文摘China has a long history of coal mining,among which open-pit coal mines have a large number of small coal mine goafs underground.The distribution,shape,structure and other characteristics of goafs are isolated and discontinuous,and there is no definite geological law to follow,which seriously threatens the safety of coal mine production and personnel life.Conventional ground geophysical methods have low accuracy in detecting goaf areas affected by mechanical interference from open-pit mines,especially for waterless goaf areas,which cannot be detected by existing methods.This article proposes the use of high-frequency electromagnetic waves for goaf detection.The feasibility of using drilling radar to detect goaf was theoretically analyzed,and a goaf detection model was established.The response characteristics of different fillers in the goaf under different frequencies of high-frequency electromagnetic waves were simulated and analyzed.In a certain open-pit mine in Inner Mongolia,100MHz high-frequency electromagnetic waves were used to detect the goaf through directional drilling on the ground.After detection,excavation verification was carried out,and the location of one goaf detected was verified.The results of engineering practice show that the application of high-frequency electromagnetic waves in goaf detection expands the detection radius of boreholes,has the advantages of high efficiency and accuracy,and has important theoretical and practical significance.
