Underground fires are a smoldering combustion with a slow spread rate, low temperatures and no flame. They can last from days to several months, and can even become overwintering fires. They are difficult to find, lea...Underground fires are a smoldering combustion with a slow spread rate, low temperatures and no flame. They can last from days to several months, and can even become overwintering fires. They are difficult to find, leading to considerable damage to the forests. The moisture content of combustible fuels is an important factor in the occurrence and persistence of underground forest fires. The Daxing’an Mountains are a hot spot for underground fires in China. This paper looks at the influence of different moisture contents on underground fire characteristics using simulation combustion experiments in the laboratory. The study showed that peak temperature and spread rate fluctuation of humus at different moisture levels increased with humus depth. Peak temperature and spread rate fluctuation of humus at different depths decreased with increased moisture;moisture content and depth of humus had a significant effect on peak temperature and spread rate fluctuation;peak temperature at different depths decreased with increased moisture;the spread rate in upper layers increased with moisture content, while the spread rate in the lower layers decreased with increased moisture content.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
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 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
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
The results from a number of investigations and fire experiments are presented and analyzed in order to characterize the fire behavior of mining vehicles in underground hard rock mines. The analysis also includes fire...The results from a number of investigations and fire experiments are presented and analyzed in order to characterize the fire behavior of mining vehicles in underground hard rock mines. The analysis also includes fire safety and fire protection measures with respect to the mining vehicle fire behavior.Earlier studies on fires in underground hard rock mines have shown that vehicles or mobile equipment are the dominant sources of fire. A better knowledge about the fire behavior of vehicles in underground hard rock mines is therefore needed. During the analysis the direction and flow rate of the ventilation in a drift was found to have a significant impact on the fire behavior, causing for example flame tilt with rapid fire spread. The shielded sections of a vehicle will be less affected by the ventilation flow resulting in for example a decreased flame spread. It was also found that spray fires may result in considerable heat release rate but are generally of shorter duration and will not make any significant contributions to the overall heat release rate of the fully developed vehicle fire. The fire duration of a loader tire from a full-scale fire experiment was found to be at least 200 min and will largely determine the total fire duration of the vehicle. A different scenario with different conditions with for example a slower flame spread resulted in an even longer fire duration. The radiative and convective fraction will be a key factor when determining the heat transfer mechanisms involved in a fire and will vary from material to material.Calculations show that the radiative fraction of the tire fires on two mining vehicles is significantly lower than found in earlier experiments. The design and construction of the mining vehicle will have an important impact on the fire behavior and could possibly mitigate the consequences of a fire and allow fire personnel to extinguish a fire that otherwise would have had a too high heat release rate.展开更多
Underground coal fires are one of the most common and serious geohazards in most coal producing countries in the world. Monitoring their spatio-temporal changes plays an important role in controlling and preventing th...Underground coal fires are one of the most common and serious geohazards in most coal producing countries in the world. Monitoring their spatio-temporal changes plays an important role in controlling and preventing the effects of coal fires, and their environmental impact. In this study, the spatio-temporal changes of underground coal fires in Khanh Hoa coal field(North-East of Viet Nam) were analyzed using Landsat time-series data during the 2008-2016 period. Based on land surface temperatures retrieved from Landsat thermal data, underground coal fires related to thermal anomalies were identified using the MEDIAN+1.5×IQR(IQR: Interquartile range) threshold technique. The locations of underground coal fires were validated using a coal fire map produced by the field survey data and cross-validated using the daytime ASTER thermal infrared imagery. Based on the fires extracted from seven Landsat thermal imageries, the spatiotemporal changes of underground coal fire areas were analyzed. The results showed that the thermalanomalous zones have been correlated with known coal fires. Cross-validation of coal fires using ASTER TIR data showed a high consistency of 79.3%. The largest coal fire area of 184.6 hectares was detected in 2010, followed by 2014(181.1 hectares) and 2016(178.5 hectares). The smaller coal fire areas were extracted with areas of 133.6 and 152.5 hectares in 2011 and 2009 respectively. Underground coal fires were mainly detected in the northern and southern part, and tend to spread to north-west of the coal field.展开更多
With the large-scale mining of coal resources,the huge economic losses and environmental problems caused by underground coal fires have become increasingly prominent,and the research on the status quo and response str...With the large-scale mining of coal resources,the huge economic losses and environmental problems caused by underground coal fires have become increasingly prominent,and the research on the status quo and response strategies of underground coal fires is of great significance to accelerate the green prevention and control of coal fires,energy conservation and emission reduction.In this paper,we summarized and sorted out the research status of underground coal fires,focused on the theoretical and technical issues such as underground coal fire combustion mechanism,multiphysics coupling effect of coal fire combustion,fire prevention and extinguishing technology for underground coal fires,and beneficial utilization technology,and described the latest research progress of the prevention and control for underground coal fire hazards.Finally,the key research problems in the field of underground coal fire hazards prevention and control were proposed in the direction of the basic theory,technology research,comprehensive management and utilization,with a view to providing ideas and solutions for the management of underground coal fires.展开更多
From the view of underground coal mining safety system, it is extremely important to continuous monitoring of coal mines for the prompt detection of fires or related problems inspite of its uncertainty and imprecise c...From the view of underground coal mining safety system, it is extremely important to continuous monitoring of coal mines for the prompt detection of fires or related problems inspite of its uncertainty and imprecise characteristics. Therefore, evaluation and inferring the data perfectly to prevent fire related accidental risk in underground coal mining (UMC) system are very necessary. In the present article, we have proposed a novel type-2 fuzzy logic system (T2FLS) for the prediction of fire intensity and its risk assessment for risk reduction in an underground coal mine. Recently, for the observation of underground coal mines, wireless underground sensor network (WUSN) are being concerned frequently. To implement this technique IT2FLS, main functional components are sensor nodes which are installed in coal mines to accumulate different imprecise environmental data like, temperature, relative humidity, different gas concentrations etc. and these are sent to a base station which is connected to the ground observation system through network. In the present context, a WUSN based fire monitoring system is developed using fuzzy logic approach to enhance the consistency in decision making system to improve the risk chances of fire during coal mining. We have taken Mamdani IT2FLS as fuzzy model on coal mine monitoring data to consider real-time decision making (DM). It is predicted from the simulated results that the recommended system is highly acceptable and amenable in the case of fire hazard safety with compared to the wired and off-line monitoring system for UMC. Legitimacy of the suggested model is prepared using statistical analysis and multiple linear regression analysis.展开更多
One of the major safety issues in coal mining is heatings and the resultant spontaneous combustion in underground coal mines. CSIRO researchers have developed a number of polymer gels suitable for controlling beatings...One of the major safety issues in coal mining is heatings and the resultant spontaneous combustion in underground coal mines. CSIRO researchers have developed a number of polymer gels suitable for controlling beatings in coal mines. These gels were developed to meet strict selection criteria including easy preparation, no or low toxicity, controllable gelation time, adaptable to mine water chemistry, adjustable viscosity, relatively long gel life, thermally and chemically stable and low cost. The HPAM-Aluminum Citrate gel system was identified to be the most favourable gel system for fire suppression in under- ground coal mines. These gels can be applied to the areas undergoing coal heating or gas leakage at a controllable gelation time and impermeable gel barriers can be formed in the areas to block ingress of air.展开更多
The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. ...The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. In addition, the cause for a middle to a high heat value of water gas was described. And the reasonableness and feasiblity of the method was proved, showing that the double fire two stage gasification is an important technique for commercialized production.展开更多
Compared with the space on the ground,if there is a fire in the urban complex underground space,the loss will be greatly harmful.In addition,the complex underground space is usually connected with other large space ar...Compared with the space on the ground,if there is a fire in the urban complex underground space,the loss will be greatly harmful.In addition,the complex underground space is usually connected with other large space areas and densely populated.Once a fire occurs in the complex underground space,it will cause huge property losses and casualties.In order to reduce the risk of fire,it is necessary to deeply understand the development rules and characteristics of fire in the complex underground space of the city.This article has mainly carried on the following work:(I)A particularly complex model of the multi‐storey subway station was built.On this basis,three groups of comparative experiments were conducted to study the effects of fire power,fire location and smoke control system on fire development,and the conclusion that fire location is the most important factor for fire development was obtained;(II)In order to explore the entire space fire and the local space fire,CFD(Computational Fluid Dynamics)is used to build a large‐size fire model and a small‐size fire model respectively;(III)Multiple detector data as temperature slices were built,and it is expected to make full use of the simulation data to deduce the important index of fire location in the early stage of fire.All of the works in this paper will provide reference experimental data for the prevention and firefighting of a sudden fire in the complex underground space.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
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
基金financially supported by the National Natural Science Foundation of China (31971669)the Postgraduate Innovation Project of Beihua University (2021-013)
文摘Underground fires are a smoldering combustion with a slow spread rate, low temperatures and no flame. They can last from days to several months, and can even become overwintering fires. They are difficult to find, leading to considerable damage to the forests. The moisture content of combustible fuels is an important factor in the occurrence and persistence of underground forest fires. The Daxing’an Mountains are a hot spot for underground fires in China. This paper looks at the influence of different moisture contents on underground fire characteristics using simulation combustion experiments in the laboratory. The study showed that peak temperature and spread rate fluctuation of humus at different moisture levels increased with humus depth. Peak temperature and spread rate fluctuation of humus at different depths decreased with increased moisture;moisture content and depth of humus had a significant effect on peak temperature and spread rate fluctuation;peak temperature at different depths decreased with increased moisture;the spread rate in upper layers increased with moisture content, while the spread rate in the lower layers decreased with increased moisture content.
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.
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 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”.
文摘The results from a number of investigations and fire experiments are presented and analyzed in order to characterize the fire behavior of mining vehicles in underground hard rock mines. The analysis also includes fire safety and fire protection measures with respect to the mining vehicle fire behavior.Earlier studies on fires in underground hard rock mines have shown that vehicles or mobile equipment are the dominant sources of fire. A better knowledge about the fire behavior of vehicles in underground hard rock mines is therefore needed. During the analysis the direction and flow rate of the ventilation in a drift was found to have a significant impact on the fire behavior, causing for example flame tilt with rapid fire spread. The shielded sections of a vehicle will be less affected by the ventilation flow resulting in for example a decreased flame spread. It was also found that spray fires may result in considerable heat release rate but are generally of shorter duration and will not make any significant contributions to the overall heat release rate of the fully developed vehicle fire. The fire duration of a loader tire from a full-scale fire experiment was found to be at least 200 min and will largely determine the total fire duration of the vehicle. A different scenario with different conditions with for example a slower flame spread resulted in an even longer fire duration. The radiative and convective fraction will be a key factor when determining the heat transfer mechanisms involved in a fire and will vary from material to material.Calculations show that the radiative fraction of the tire fires on two mining vehicles is significantly lower than found in earlier experiments. The design and construction of the mining vehicle will have an important impact on the fire behavior and could possibly mitigate the consequences of a fire and allow fire personnel to extinguish a fire that otherwise would have had a too high heat release rate.
基金funded by the Ministry-level Scientific and Technological Key Programs of Ministry of Natural Resources and Environment of Viet Nam "Application of thermal infrared remote sensing and GIS for mapping underground coal fires in Quang Ninh coal basin" (Grant No. TNMT.2017.08.06)
文摘Underground coal fires are one of the most common and serious geohazards in most coal producing countries in the world. Monitoring their spatio-temporal changes plays an important role in controlling and preventing the effects of coal fires, and their environmental impact. In this study, the spatio-temporal changes of underground coal fires in Khanh Hoa coal field(North-East of Viet Nam) were analyzed using Landsat time-series data during the 2008-2016 period. Based on land surface temperatures retrieved from Landsat thermal data, underground coal fires related to thermal anomalies were identified using the MEDIAN+1.5×IQR(IQR: Interquartile range) threshold technique. The locations of underground coal fires were validated using a coal fire map produced by the field survey data and cross-validated using the daytime ASTER thermal infrared imagery. Based on the fires extracted from seven Landsat thermal imageries, the spatiotemporal changes of underground coal fire areas were analyzed. The results showed that the thermalanomalous zones have been correlated with known coal fires. Cross-validation of coal fires using ASTER TIR data showed a high consistency of 79.3%. The largest coal fire area of 184.6 hectares was detected in 2010, followed by 2014(181.1 hectares) and 2016(178.5 hectares). The smaller coal fire areas were extracted with areas of 133.6 and 152.5 hectares in 2011 and 2009 respectively. Underground coal fires were mainly detected in the northern and southern part, and tend to spread to north-west of the coal field.
基金supported by the National Natural Science Foundation of China (52174229)the Natural Science Foundation of Liaoning Province (2021-KF-23-01),for which the authors are very thankful.
文摘With the large-scale mining of coal resources,the huge economic losses and environmental problems caused by underground coal fires have become increasingly prominent,and the research on the status quo and response strategies of underground coal fires is of great significance to accelerate the green prevention and control of coal fires,energy conservation and emission reduction.In this paper,we summarized and sorted out the research status of underground coal fires,focused on the theoretical and technical issues such as underground coal fire combustion mechanism,multiphysics coupling effect of coal fire combustion,fire prevention and extinguishing technology for underground coal fires,and beneficial utilization technology,and described the latest research progress of the prevention and control for underground coal fire hazards.Finally,the key research problems in the field of underground coal fire hazards prevention and control were proposed in the direction of the basic theory,technology research,comprehensive management and utilization,with a view to providing ideas and solutions for the management of underground coal fires.
文摘From the view of underground coal mining safety system, it is extremely important to continuous monitoring of coal mines for the prompt detection of fires or related problems inspite of its uncertainty and imprecise characteristics. Therefore, evaluation and inferring the data perfectly to prevent fire related accidental risk in underground coal mining (UMC) system are very necessary. In the present article, we have proposed a novel type-2 fuzzy logic system (T2FLS) for the prediction of fire intensity and its risk assessment for risk reduction in an underground coal mine. Recently, for the observation of underground coal mines, wireless underground sensor network (WUSN) are being concerned frequently. To implement this technique IT2FLS, main functional components are sensor nodes which are installed in coal mines to accumulate different imprecise environmental data like, temperature, relative humidity, different gas concentrations etc. and these are sent to a base station which is connected to the ground observation system through network. In the present context, a WUSN based fire monitoring system is developed using fuzzy logic approach to enhance the consistency in decision making system to improve the risk chances of fire during coal mining. We have taken Mamdani IT2FLS as fuzzy model on coal mine monitoring data to consider real-time decision making (DM). It is predicted from the simulated results that the recommended system is highly acceptable and amenable in the case of fire hazard safety with compared to the wired and off-line monitoring system for UMC. Legitimacy of the suggested model is prepared using statistical analysis and multiple linear regression analysis.
文摘One of the major safety issues in coal mining is heatings and the resultant spontaneous combustion in underground coal mines. CSIRO researchers have developed a number of polymer gels suitable for controlling beatings in coal mines. These gels were developed to meet strict selection criteria including easy preparation, no or low toxicity, controllable gelation time, adaptable to mine water chemistry, adjustable viscosity, relatively long gel life, thermally and chemically stable and low cost. The HPAM-Aluminum Citrate gel system was identified to be the most favourable gel system for fire suppression in under- ground coal mines. These gels can be applied to the areas undergoing coal heating or gas leakage at a controllable gelation time and impermeable gel barriers can be formed in the areas to block ingress of air.
基金Supported by National Natural Science Foundation of China(5 990 60 14 )
文摘The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. In addition, the cause for a middle to a high heat value of water gas was described. And the reasonableness and feasiblity of the method was proved, showing that the double fire two stage gasification is an important technique for commercialized production.
基金supported by Shenzhen Science and Technology Innovation Commission(NO.KCXFZ20211020163402004).
文摘Compared with the space on the ground,if there is a fire in the urban complex underground space,the loss will be greatly harmful.In addition,the complex underground space is usually connected with other large space areas and densely populated.Once a fire occurs in the complex underground space,it will cause huge property losses and casualties.In order to reduce the risk of fire,it is necessary to deeply understand the development rules and characteristics of fire in the complex underground space of the city.This article has mainly carried on the following work:(I)A particularly complex model of the multi‐storey subway station was built.On this basis,three groups of comparative experiments were conducted to study the effects of fire power,fire location and smoke control system on fire development,and the conclusion that fire location is the most important factor for fire development was obtained;(II)In order to explore the entire space fire and the local space fire,CFD(Computational Fluid Dynamics)is used to build a large‐size fire model and a small‐size fire model respectively;(III)Multiple detector data as temperature slices were built,and it is expected to make full use of the simulation data to deduce the important index of fire location in the early stage of fire.All of the works in this paper will provide reference experimental data for the prevention and firefighting of a sudden fire in the complex underground space.
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.
