Deep Underground Science and Engineering(DUSE)is pleased to release this issue with feature articles reporting the advancement in several research topics related to deep underground.This issue contains one perspective...Deep Underground Science and Engineering(DUSE)is pleased to release this issue with feature articles reporting the advancement in several research topics related to deep underground.This issue contains one perspective article,two review articles,six research articles,and one case study article.These articles focus on underground energy storage,multiscale modeling for correlation between micro-scale damage and macro-scale structural degradation,mineralization and formation of gold mine,interface and fracture seepage,experimental study on tunnel-sand-pile interaction,and high water-content materials for deep underground space backfilling,analytical solutions for the crack evolution direction in brittle rocks,and a case study on the squeezing-induced failure in a water drainage tunnel and the rehabilitation measures.展开更多
Soft rock is one of the common geological conditions in coal mine underground water reservoir engineering.The cross-scale correlation analysis of water erosion soft lithology deterioration is very important for the sa...Soft rock is one of the common geological conditions in coal mine underground water reservoir engineering.The cross-scale correlation analysis of water erosion soft lithology deterioration is very important for the safety and stability of coal mine underground reservoir(CMUR)engineering.To address the issues of grain crowding and segmentation difficulties in cross-scale corelation analysis,as well as the limitations of traditional etching methods,this study proposes an image grain segmentation method based on deep learning algorithms,utilizing scanning electron microscopy and image process-ing techniques.The method successfully segments crowded grains and eliminates the interference from misplaced particles.In addition,indoor uniaxial compression tests were conducted to obtain the mechanical properties of sandstone samples with different water content.By quantitatively characterizing the macroscopic and microscopic deterioration degree of red sandstone samples with different water contents,the relationship between the strength changes of rock samples and the pet-rographic parameters such as grain size and grain shape is analyzed,and the influence law of soft lithology deterioration in CMUR engineering is revealed.The results indicate:(1)Water significantly weakens the mechanical properties and stability of soft rock.With increasing water content,the strength of sandstone samples continuously decreases,and the failure mode transitions from brittle to ductile failure.(2)The deterioration of micro-micro structures is the main cause of the decrease in mechanical properties of water-eroded soft rock.Grain size,grain area,and aspect ratio are negatively correlated with water content,indicating that hydrophilic minerals in soft rock dissolve under the action of water,leading to rock damage.(3)Grain size,area,and aspect ratio can serve as significant indicators for quantifying the strength changes of water-eroded soft rock.The research findings can be applied to stability assessment and disaster prevention in CMUR engineering.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
To investigate the fracture propagation characteristics and failure mechanism of anti-dip rock slope induced by underground mining,the Jiguanling landslide in Wulong,Chongqing,China is taken as the prototype,and physi...To investigate the fracture propagation characteristics and failure mechanism of anti-dip rock slope induced by underground mining,the Jiguanling landslide in Wulong,Chongqing,China is taken as the prototype,and physical model test is utilized to study the fracture evolution process,deformation characteristics and failure mechanism of anti-dip rock slope.In this study,the digital image correlation(DIC)technique and pressure acquisition system are combined to analyze the displacement and stress field of rock slope during underground mining stages.The results show that the anti-dip rock slope experiences four stages during underground coal mining:tensile fracture propagation in upper toppling zone,shallow damage in the lower shear zone,coal seam roof caving,failure of the whole slope.There is a phenomenon of local tensile and compressive stress conversion in upper toppling zone after roof caving.The appearance of coal seam roof caving increases the compressive area and pressure of the shear zone,leading to the failure of the shear blocks at the front edge,and ultimately causing failure of the whole slope.Mining with retained coal pillar before shallow failure in the shear zone can effectively block the impact of lower mining on the upper toppling zone,achieve a 16%contraction in toppling zone,and improve the stability of the slope.The failure mode of slope can be summarized as shear–slip–toppling collapse failure.This paper improves the understanding on the failure mechanism of anti-dip rock slope caused by underground mining.展开更多
This special issue of Deep Underground Science and Engineering(DUSE)showcases pioneering research on the transformative role of machine learning(ML)and Big Data in deep underground engineering.Edited by vip editors ...This special issue of Deep Underground Science and Engineering(DUSE)showcases pioneering research on the transformative role of machine learning(ML)and Big Data in deep underground engineering.Edited by vip editors Prof.Asoke Nandi(Brunel University of London,UK),Prof.Ru Zhang(Sichuan University,China),Prof.Tao Zhao(Chinese Academy of Sciences,China),and Prof.Tao Lei(Shaanxi University of Science and Technology,China),this issue highlights the innovative applications of ML technique in reshaping structural safety,tunneling operations,and geotechnical investigations.展开更多
The supply of energy is a severe challenge for every country,particularly those that are industrially developed and highly populated.Natural gas is among the most essential energy sources due to its reasonably low cos...The supply of energy is a severe challenge for every country,particularly those that are industrially developed and highly populated.Natural gas is among the most essential energy sources due to its reasonably low cost and high heating value.One of the elements of a sustainable energy supply is underground gas storage(UGS).UGS systems consist of a cushion gas(base gas)and a working gas.The cushion gas is injected into a reservoir to sustain the pressure and remain there until the period of storage ends,while the working gas is the main gas to be stored and produced.Unlike prior studies on fully depleted fields,our research emphasizes the potential of UGS in the presence of remaining oil and integrates key concepts,such as enhanced oil recovery and CO_(2)sequestration.A simulation study was conducted using Qatari Advanced Simulator for Reservoirs software to determine the feasibility of a UGS system in a partially depleted oil reservoir.N_(2) and CO_(2)gases were considered and analyzed over short,medium,and long injection/withdrawal cycles to investigate their potential as cushion gases for natural gas storage in a partially depleted oil reservoir.It was found that using CO_(2)as a cushion gas produces 32%,57%,and 90%of CH_(4) according to short-,medium-,and long-term energy storage scenarios,respectively,with the CH_(4) production higher than when using N2.This study sheds light on the feasibility of implementing underground gas storage systems in partially depleted oil reservoirs.展开更多
The big underground powerhouse cavern of the China Baihetan hydropower plant is 438m long,34m wide,and 88.7m high.It is cut by a weak interlayer shear zone and its high sidewall poses a huge stability problem.This pap...The big underground powerhouse cavern of the China Baihetan hydropower plant is 438m long,34m wide,and 88.7m high.It is cut by a weak interlayer shear zone and its high sidewall poses a huge stability problem.This paper reports our successful solution of this problem through numerical simulations and a replacement-tunnel scheme in the detailed design stage and close site monitoring in the excavation stage.Particularly,in the detail design stage,mechanical parameters of the shear zone were carefully determined through laboratory experiments and site tests.Then,deformation of the surrounding rocks and the shear zone under high in situ stress conditions was predicted using 3 Dimensional Distinct Element Code(3DEC).Subsequently,a replacement-tunnel scheme was proposed for the treatment on the shear zone to prevent severe unloading relaxation of surrounding rocks.In the construction period,excavation responses were closely monitored on deformations of surrounding rocks and the shear zone.The effect of local cracking in the replacement tunnels on sidewall stability was evaluated using the strength reduction method.These monitoring results were compared with the predicted numerical simulation in the detailed design stage.It is found that the shear zone greatly modified the deformation mode of the cavern surrounding rocks.Without any treatment,rock mass deformation on the downstream sidewall was larger than 125mm and the shearing deformation of the shear zone was 60–70 mm.These preset replacement tunnels can reduce not only the unloading and relaxation of rock masses but also the maximum shearing deformation of the shear zone by 10–20 mm.The predictions by numerical simulation were in good agreement with the monitoring results.The proposed tunnel-replacement scheme can not only restrain the shear zone deformation but also enhance the safety of surrounding rocks and concrete tunnels.This design procedure offers a good reference for interaction between a big underground cavern and a weak layer zone in the future.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
Within the transition process of urban rail transit systems,the challenges of high energy consumption,increasing carbon emissions,limited economic viability,and intricate risks emerge as significant hurdles.This paper...Within the transition process of urban rail transit systems,the challenges of high energy consumption,increasing carbon emissions,limited economic viability,and intricate risks emerge as significant hurdles.This paper proposes a novel energy utilization framework for the urban rail transit system that incorporates underground energy storage systems characterized by high resilience and low carbon.First,existing methods employed in urban rail transit are comprehensively reviewed.Then,a novel framework and strategic significance of the urban rail transit system incorporating underground energy storage systems are introduced.This integration effectively utilizes and manages diverse renewable energy sources and the available space resources.The viability is demonstrated through a case study by combining Nanjing metro.Finally,suggestions for research in pivotal areas are summarized.展开更多
Urban growth has promoted the use of underground spaces,where explosion accidents can be catastrophic.In this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane ex...Urban growth has promoted the use of underground spaces,where explosion accidents can be catastrophic.In this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane explosion protection by using an experimental platform and adjusting the blockage rate and spacing of the obstacles.It aims to reduce the risk of gas explosions in urban underground spaces.The results of the study show that the flame propagation peak speed and peak overpressure are reduced with the decrease in the blocking rate of the flexible obstacle when the blocking rate of the flexible obstacle is less than or equal to the blocking rate of the rigid obstacle,with the decrease in the spacing,the better the protection effect of the methane explosion.When the blockage rate of the flexible obstacle is greater than the blockage rate of the rigid obstacle and spacing is less than the height of the flexible obstacle,rigid and flexible obstacles are connected as a whole,increasing the strength of the explosion.This study can provide a theoretical basis and scientific guidance for optimizing rigid and flexible object hybrid layouts and methane explosion protection technology in urban underground spaces.展开更多
Geo-monitoring provides quantitative and reliable information to identify hazards and adopt appropriate measures timely.However,this task inherently exposes monitoring staff to hazardous environments,especially in und...Geo-monitoring provides quantitative and reliable information to identify hazards and adopt appropriate measures timely.However,this task inherently exposes monitoring staff to hazardous environments,especially in underground settings.Since 2000s,robots have been widely applied in various fields and many studies have focused on establishing autonomous mobile robotic systems as well as solving the issue of underground navigation and mapping.However,only a few studies have conducted quantitative evaluations of these methods,and almost none have provided a systematic and comprehensive assessment of the suitability of mapping robots for underground geo-monitoring.In this study,a methodology for objective and quantitative assessment of the applicability of SLAM methods in underground geo-monitoring is proposed.This involves the development of an underground test field and some specific metrics,which allow detailed local accuracy analysis of point measurements,line segments,and areas using artificial targets.With this proposed methodology,a series of repeated experimental measurements has been performed with an autonomous driving robot and the selected LiDAR-and visual-based SLAM methods.The resulting point cloud was compared with the reference data measured by a total station and a terrestrial laser scanner.The accuracy and precision of the selected SLAM methods as well as the verifiability and reliability of the results are evaluated and discussed by analysing quantities such as the deviations of the control points coordinates,cloudto-cloud distances between the test and reference point cloud,normal vector,centre point coordinates and area of the planar objects.The results demonstrate that the HDL Graph SLAM achieves satisfactory precision,accuracy,and repeatability with a mean cloud-to-cloud distance of 0.12 m(with a standard deviation of 0.13 m)in an 80 m closed-loop measurement area.Although RTAB-Map exhibits better plane-capturing capabilities,the measurement results reveal instability and inaccuracies.展开更多
Coal pillars are critical supporting structures between underground coal gasification gasifiers.Its bearing capacity and structural stability are severely threatened by high-temperature environments.To elucidate the h...Coal pillars are critical supporting structures between underground coal gasification gasifiers.Its bearing capacity and structural stability are severely threatened by high-temperature environments.To elucidate the high-temperature deterioration mechanism of coal pillars at multiple scales,coal strength features as a function of temperature were investigated via uniaxial compression and acoustic emission equipment.The pyrolysis reaction process and microstructure evolution were characterized via X-ray diffractometer(XRD),scanning electron microscope(SEM),thermogravimetric(TG),Fourier transform infrared spectroscopy(FTIR),and computed tomography(CT)tests.Experimental results reveal a critical temperature threshold of 500℃for severe degradation of the coal bearing capacity.Specifically,both the strength and elastic modulus exhibit accelerated degradation above this temperature,with maximum reductions of 45.53%and 61.34%,respectively.Above 500℃,coal essentially undergoes a pyrolysis reaction under N_(2)and CO_(2)atmospheres.High temperatures decrease the quantity of O_(2)-based functional groups,growing aromaticity and the degree of graphitization.These changes induce dislocation and slip inside the coal crystal nucleus and then lead to deformation of the coal molecular structural units and strain energy generation.This process results in a great increase in porosity.Consequently,the stress deformation of coal increases,transforming the type of failure from brittle to ductile failure.These findings are expected to provide scientific support for UCG rock strata control.展开更多
[Objectives]This study was conducted to investigate water pollution in the Huanghou Underground River Basin.[Methods]Five representative water quality indicators,ammonia nitrogen(NH+4-N),nitrate nitrogen(NO_(3)^(-)-N)...[Objectives]This study was conducted to investigate water pollution in the Huanghou Underground River Basin.[Methods]Five representative water quality indicators,ammonia nitrogen(NH+4-N),nitrate nitrogen(NO_(3)^(-)-N),permanganate index(COD Mn),total phosphorus(TP),and nitrite nitrogen(NO_(2)^(-)-N),were selected.The single-factor pollution index(P i),Nemerow pollution index(P N),and water quality index(WQI)were calculated to quantitatively assess pollution characteristics and evaluate water quality in the basin.[Results]The overall water quality in the Huanghou Underground River Basin fell within the"slightly polluted to good"range,with pollution primarily concentrated in the upstream areas.The downstream water quality was generally better,as most pollutants from the upstream were diluted or degraded during migration,resulting in little impact on the downstream areas.[Conclusions]This study provides a theoretical basis for understanding the pollution characteristics and evaluation of water quality in the Huanghou Underground River Basin.展开更多
Gas explosions are a frequent hazard in underground confined spaces in the process of urban development.Liquid sedimentary layers,commonly present in these environments,have not been sufficiently studied in terms of t...Gas explosions are a frequent hazard in underground confined spaces in the process of urban development.Liquid sedimentary layers,commonly present in these environments,have not been sufficiently studied in terms of their impact on explosion dynamics.This study aims to investigate how gas-liquid two-phase environments in confined underground spaces affect the explosion characteristics of natural gas.To achieve this,experiments are conducted to examine the propagation of natural gas explosions in water and diesel layers,focusing on the influence of liquid properties and the liquid fullness degree(Lx)on explosion behavior.The results indicate that the presence of a liquid layer after the initial ignition stage significantly attenuates both the peak overpressure and the rise speed of pressure,in comparison to the natural gas conditions.During the subsequent explosive reaction,the evaporation and combustion of the diesel surface resulted in a distinct double-peak pressure rise profile in the diesel layer,with the second peak notably exceeding the first peak.Under conditions with a liquid sedimentary layer,the flame propagation velocities range from 6.53 to 34.1 m/s,while the overpressure peaks vary between 0.157 and 0.255 MPa.The explosion duration in both the water and diesel layer environments is approximately twice as long as that of the natural gas explosion,although the underlying mechanisms differ.In the diesel layer,the prolonged explosion time is attributed to the evaporation and combustion of the diesel,while in the water layer,the flame propagation velocity is significantly reduced.Under the experimental conditions,the maximum explosion energy reached 7.15×10~6J,corresponding to a TNT equivalent of 1.7.The peak overpressure surpassed the threshold for human fatality as defined by overpressure standards,posing a potential risk of damage to large steel-frame structures.The explosion shockwave in diesel layer conditions(L_(d)=0%,5%,7.5%,12.5%)and water layer(L_(w)=12.5%)conditions is observed to be sufficient to damage earthquake-resistant reinforced concrete.This study investigates the impact of sediment layer thickness and composition on gas explosions,and evaluates the associated explosion energy to assess human injuries and structural damage in underground environments.The findings of this study provide a scientific reference for urban underground safety.展开更多
Surface space constraints and the associated massive carbon emissions present significant challenges to the sustainable development of megacities.Urban underground space(UUS)construction is expected to provide a pract...Surface space constraints and the associated massive carbon emissions present significant challenges to the sustainable development of megacities.Urban underground space(UUS)construction is expected to provide a practical approach for alleviating the space constraints of surface construction.However,indepth examinations of the overall UUS system to reveal carbon emissions in the complex matrix are lacking.This study demonstrates the vital role of UUS development in achieving carbon neutrality using a streamlined life-cycle assessment method.Carbon emissions and the mitigation potential of building underground spaces,metro systems,and geothermal energy sources are analyzed.The construction of underground spaces in buildings is the largest carbon emitter within the entire UUS system,releasing a considerable 547.2 Mt in 2020.However,geothermal carbon sequestration,a significant element of the UUS system,provided an unexpected and impressive contribution,sequestering 170 Mt of carbon in 2020.This study shows that UUS addresses the lack of space for urban development and is a lowcarbon method of urban construction.Therefore,developing low-carbon building technologies and improving the UUS development model is imperative to achieving better low-carbon balance.This helps to promote more coordinated and sustainable urban development.展开更多
The Rock-soil interface is a common geological interface.Due to mechanical differences between soil and rock,the stress waves generated by underground blasting undergo intense polarization when crossing the rock-soil ...The Rock-soil interface is a common geological interface.Due to mechanical differences between soil and rock,the stress waves generated by underground blasting undergo intense polarization when crossing the rock-soil interface,making propagation laws difficult to predict.Currently,the characteristics of the impact of the rock-soil interface on blasting stress waves remain unclear.Therefore,the vibration field caused by cylindrical charge blasting in elastic rock and partial-saturation poro-viscoelastic soil was solved.A forward algorithm for the underground blasting vibration field in rock-soil sites was proposed,considering medium damping and geometric diffusion effects of stress waves.Further investigation into the influence of rock and soil parameters and blasting source parameters revealed the following conclusions:stress waves in soil exhibit dispersion,causing peak particle velocity(PPV)to display a discrete distribution.Soil parameters affect PPV attenuation only within the soil,while blasting source parameters affect PPV attenuation throughout the entire site.Multi-wave coupling effects induced by the rocksoil interface result in zones of enhanced and attenuated PPV within the site.The size of the enhancement zone is inversely correlated with the distance from the blasting source and positively correlated with the blasting source attenuation rate and burial depth,providing guidance for selecting explosives and blasting positions.Additionally,PPV attenuation rate increases with distance from the rock-soil interface,but an amplification effect occurs near the interface,most noticeable at 0.1 m.Thus,a sufficient safety distance from the rock-soil interface is necessary during underground blasting.展开更多
The configuration of underground powerhouses is crucial in pumped-storage hydropower projects,which play a vital role in maintaining grid stability,facilitating the integration of renewable energy sources,and managing...The configuration of underground powerhouses is crucial in pumped-storage hydropower projects,which play a vital role in maintaining grid stability,facilitating the integration of renewable energy sources,and managing flood risks.However,geotechnical challenges,such as complex joint orientations,anisotropy in in-situ stress,and rock damage caused by excavation,require thorough stability assessments.This research employs the ubiquitous anisotropic joint model within FLAC3D to investigate the effects of joint dip angle,joint dip direction,and the alignment of in-situ stress on the stability of surrounding rock formations.The key parameters analyzed include joint cohesion,friction angle,and the magnitude of in-situ stress.The numerical results indicate that deformation is minimized when the axis of the powerhouse is aligned with the major principal stress.Furthermore,joint dip angles between 65°and 70°lead to a 50%reduction in both displacement and plastic zone volume.Additionally,angles less than 40°between the joint dip direction and the powerhouse axis enhance stability.These findings provide practical recommendations for optimizing the orientation of powerhouses in geomechanical contexts similar to those characterized by foliated sericite phyllite with moderate joint persistence.展开更多
This work proposes an optimization method for gas storage operation parameters under multi-factor coupled constraints to improve the peak-shaving capacity of gas storage reservoirs while ensuring operational safety.Pr...This work proposes an optimization method for gas storage operation parameters under multi-factor coupled constraints to improve the peak-shaving capacity of gas storage reservoirs while ensuring operational safety.Previous research primarily focused on integrating reservoir,wellbore,and surface facility constraints,often resulting in broad constraint ranges and slow model convergence.To solve this problem,the present study introduces additional constraints on maximum withdrawal rates by combining binomial deliverability equations with material balance equations for closed gas reservoirs,while considering extreme peak-shaving demands.This approach effectively narrows the constraint range.Subsequently,a collaborative optimization model with maximum gas production as the objective function is established,and the model employs a joint solution strategy combining genetic algorithms and numerical simulation techniques.Finally,this methodology was applied to optimize operational parameters for Gas Storage T.The results demonstrate:(1)The convergence of the model was achieved after 6 iterations,which significantly improved the convergence speed of the model;(2)The maximum working gas volume reached 11.605×10^(8) m^(3),which increased by 13.78%compared with the traditional optimization method;(3)This method greatly improves the operation safety and the ultimate peak load balancing capability.The research provides important technical support for the intelligent decision of injection and production parameters of gas storage and improving peak load balancing ability.展开更多
With the continuous expansion of deep underground engineering and the growing demand for safety monitoring,microseismic monitoring has become a core method for early warning of rock mass fracture and engineering stabi...With the continuous expansion of deep underground engineering and the growing demand for safety monitoring,microseismic monitoring has become a core method for early warning of rock mass fracture and engineering stability assessment.To address problems in existing methods,such as low data processing efficiency and poor phase recognition accuracy under low signal-to-noise ratio(SNR)conditions in complex geological environments,this study proposes an intelligent phase picking model based on ResUNet.The model integrates the residual learning mechanism of ResNet with the multi-scale feature extraction capability of UNet,effectively mitigating the vanishing gradient problem in deep networks.It also achieves cross-layer fusion of shallow detail features and deep semantic features through skip connections in the encoder-decoder structure.Compared with traditional short-time average/long-time average(STA/LTA)algorithms and advanced neural network models such as PhaseNet and EQTransformer,ResUNet shows superior performance in picking P-and S-wave phases.The model was trained on 400000 labeled microseismic signals from the Stanford earthquake dataset(STEAD)and was successfully applied to the Shizhuyuan polymetallic mine in Hunan Province,China.The results demonstrate that ResUNet achieves high picking accuracy and robustness in complex geological conditions,offering reliable technical support for early warning of disasters such as rockburst in deep underground engineering.展开更多
Rockfalls are among the frequent hazards in underground mines worldwide,requiring effective methods for detecting unstable rock blocks to ensure miners’and equipment’s safety.This study proposes a novel approach for...Rockfalls are among the frequent hazards in underground mines worldwide,requiring effective methods for detecting unstable rock blocks to ensure miners’and equipment’s safety.This study proposes a novel approach for identifying potential rockfall zones using infrared thermal imaging and image segmentation techniques.Infrared images of rock blocks were captured at the Draa Sfar deep underground mine in Morocco using the FLUKE TI401 PRO thermal camera.Two segmentation methods were applied to locate the potential unstable areas:the classical thresholding and the K-means clustering model.The results show that while thresholding allows a binary distinction between stable and unstable areas,K-means clustering is more accurate,especially when using multiple clusters to show different risk levels.The close match between the clustering masks of unstable blocks and their corresponding visible light images further validated this.The findings confirm that thermal image segmentation can serve as an alternative method for predicting rockfalls and monitoring geotechnical issues in underground mines.Underground operators worldwide can apply this approach to monitor rock mass stability.However,further research is recommended to enhance these results,particularly through deep learning-based segmentation and object detection models.展开更多
文摘Deep Underground Science and Engineering(DUSE)is pleased to release this issue with feature articles reporting the advancement in several research topics related to deep underground.This issue contains one perspective article,two review articles,six research articles,and one case study article.These articles focus on underground energy storage,multiscale modeling for correlation between micro-scale damage and macro-scale structural degradation,mineralization and formation of gold mine,interface and fracture seepage,experimental study on tunnel-sand-pile interaction,and high water-content materials for deep underground space backfilling,analytical solutions for the crack evolution direction in brittle rocks,and a case study on the squeezing-induced failure in a water drainage tunnel and the rehabilitation measures.
基金supported by the National Natural Science Foundation of China(51774196,52304093)China Postdoctoral Science Foundation(2023M741968)Shandong Provincial Natural Science Foundation(ZR2023ME086).
文摘Soft rock is one of the common geological conditions in coal mine underground water reservoir engineering.The cross-scale correlation analysis of water erosion soft lithology deterioration is very important for the safety and stability of coal mine underground reservoir(CMUR)engineering.To address the issues of grain crowding and segmentation difficulties in cross-scale corelation analysis,as well as the limitations of traditional etching methods,this study proposes an image grain segmentation method based on deep learning algorithms,utilizing scanning electron microscopy and image process-ing techniques.The method successfully segments crowded grains and eliminates the interference from misplaced particles.In addition,indoor uniaxial compression tests were conducted to obtain the mechanical properties of sandstone samples with different water content.By quantitatively characterizing the macroscopic and microscopic deterioration degree of red sandstone samples with different water contents,the relationship between the strength changes of rock samples and the pet-rographic parameters such as grain size and grain shape is analyzed,and the influence law of soft lithology deterioration in CMUR engineering is revealed.The results indicate:(1)Water significantly weakens the mechanical properties and stability of soft rock.With increasing water content,the strength of sandstone samples continuously decreases,and the failure mode transitions from brittle to ductile failure.(2)The deterioration of micro-micro structures is the main cause of the decrease in mechanical properties of water-eroded soft rock.Grain size,grain area,and aspect ratio are negatively correlated with water content,indicating that hydrophilic minerals in soft rock dissolve under the action of water,leading to rock damage.(3)Grain size,area,and aspect ratio can serve as significant indicators for quantifying the strength changes of water-eroded soft rock.The research findings can be applied to stability assessment and disaster prevention in CMUR engineering.
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 National Natural Science Foundation of China(52474092 and 52074042).
文摘To investigate the fracture propagation characteristics and failure mechanism of anti-dip rock slope induced by underground mining,the Jiguanling landslide in Wulong,Chongqing,China is taken as the prototype,and physical model test is utilized to study the fracture evolution process,deformation characteristics and failure mechanism of anti-dip rock slope.In this study,the digital image correlation(DIC)technique and pressure acquisition system are combined to analyze the displacement and stress field of rock slope during underground mining stages.The results show that the anti-dip rock slope experiences four stages during underground coal mining:tensile fracture propagation in upper toppling zone,shallow damage in the lower shear zone,coal seam roof caving,failure of the whole slope.There is a phenomenon of local tensile and compressive stress conversion in upper toppling zone after roof caving.The appearance of coal seam roof caving increases the compressive area and pressure of the shear zone,leading to the failure of the shear blocks at the front edge,and ultimately causing failure of the whole slope.Mining with retained coal pillar before shallow failure in the shear zone can effectively block the impact of lower mining on the upper toppling zone,achieve a 16%contraction in toppling zone,and improve the stability of the slope.The failure mode of slope can be summarized as shear–slip–toppling collapse failure.This paper improves the understanding on the failure mechanism of anti-dip rock slope caused by underground mining.
文摘This special issue of Deep Underground Science and Engineering(DUSE)showcases pioneering research on the transformative role of machine learning(ML)and Big Data in deep underground engineering.Edited by vip editors Prof.Asoke Nandi(Brunel University of London,UK),Prof.Ru Zhang(Sichuan University,China),Prof.Tao Zhao(Chinese Academy of Sciences,China),and Prof.Tao Lei(Shaanxi University of Science and Technology,China),this issue highlights the innovative applications of ML technique in reshaping structural safety,tunneling operations,and geotechnical investigations.
基金support provided by Hamad bin Khalifa University,Qatar Foundation,Qatar(210028127).
文摘The supply of energy is a severe challenge for every country,particularly those that are industrially developed and highly populated.Natural gas is among the most essential energy sources due to its reasonably low cost and high heating value.One of the elements of a sustainable energy supply is underground gas storage(UGS).UGS systems consist of a cushion gas(base gas)and a working gas.The cushion gas is injected into a reservoir to sustain the pressure and remain there until the period of storage ends,while the working gas is the main gas to be stored and produced.Unlike prior studies on fully depleted fields,our research emphasizes the potential of UGS in the presence of remaining oil and integrates key concepts,such as enhanced oil recovery and CO_(2)sequestration.A simulation study was conducted using Qatari Advanced Simulator for Reservoirs software to determine the feasibility of a UGS system in a partially depleted oil reservoir.N_(2) and CO_(2)gases were considered and analyzed over short,medium,and long injection/withdrawal cycles to investigate their potential as cushion gases for natural gas storage in a partially depleted oil reservoir.It was found that using CO_(2)as a cushion gas produces 32%,57%,and 90%of CH_(4) according to short-,medium-,and long-term energy storage scenarios,respectively,with the CH_(4) production higher than when using N2.This study sheds light on the feasibility of implementing underground gas storage systems in partially depleted oil reservoirs.
基金Program of China Three Gorges Corporation,Grant/Award Number:BHT 0679-1。
文摘The big underground powerhouse cavern of the China Baihetan hydropower plant is 438m long,34m wide,and 88.7m high.It is cut by a weak interlayer shear zone and its high sidewall poses a huge stability problem.This paper reports our successful solution of this problem through numerical simulations and a replacement-tunnel scheme in the detailed design stage and close site monitoring in the excavation stage.Particularly,in the detail design stage,mechanical parameters of the shear zone were carefully determined through laboratory experiments and site tests.Then,deformation of the surrounding rocks and the shear zone under high in situ stress conditions was predicted using 3 Dimensional Distinct Element Code(3DEC).Subsequently,a replacement-tunnel scheme was proposed for the treatment on the shear zone to prevent severe unloading relaxation of surrounding rocks.In the construction period,excavation responses were closely monitored on deformations of surrounding rocks and the shear zone.The effect of local cracking in the replacement tunnels on sidewall stability was evaluated using the strength reduction method.These monitoring results were compared with the predicted numerical simulation in the detailed design stage.It is found that the shear zone greatly modified the deformation mode of the cavern surrounding rocks.Without any treatment,rock mass deformation on the downstream sidewall was larger than 125mm and the shearing deformation of the shear zone was 60–70 mm.These preset replacement tunnels can reduce not only the unloading and relaxation of rock masses but also the maximum shearing deformation of the shear zone by 10–20 mm.The predictions by numerical simulation were in good agreement with the monitoring results.The proposed tunnel-replacement scheme can not only restrain the shear zone deformation but also enhance the safety of surrounding rocks and concrete tunnels.This design procedure offers a good reference for interaction between a big underground cavern and a weak layer zone in the future.
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supported by the National Natural Science Foundation of China(Grant numbers 52177112 and 52278419)the Chinese Academy of Engineering(Grant number 2022--XY-75).
文摘Within the transition process of urban rail transit systems,the challenges of high energy consumption,increasing carbon emissions,limited economic viability,and intricate risks emerge as significant hurdles.This paper proposes a novel energy utilization framework for the urban rail transit system that incorporates underground energy storage systems characterized by high resilience and low carbon.First,existing methods employed in urban rail transit are comprehensively reviewed.Then,a novel framework and strategic significance of the urban rail transit system incorporating underground energy storage systems are introduced.This integration effectively utilizes and manages diverse renewable energy sources and the available space resources.The viability is demonstrated through a case study by combining Nanjing metro.Finally,suggestions for research in pivotal areas are summarized.
基金supported by the National Natural Science Foundation of China(Grant No.52274177)Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202401501)+1 种基金Chongqing Graduate Student Research Innovation Program(Grant No.CYS240800)The Science and Technology Innovation Project for Graduate Students of Chongqing University of Science and Technology(Grant No.YKJCX2420702).
文摘Urban growth has promoted the use of underground spaces,where explosion accidents can be catastrophic.In this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane explosion protection by using an experimental platform and adjusting the blockage rate and spacing of the obstacles.It aims to reduce the risk of gas explosions in urban underground spaces.The results of the study show that the flame propagation peak speed and peak overpressure are reduced with the decrease in the blocking rate of the flexible obstacle when the blocking rate of the flexible obstacle is less than or equal to the blocking rate of the rigid obstacle,with the decrease in the spacing,the better the protection effect of the methane explosion.When the blockage rate of the flexible obstacle is greater than the blockage rate of the rigid obstacle and spacing is less than the height of the flexible obstacle,rigid and flexible obstacles are connected as a whole,increasing the strength of the explosion.This study can provide a theoretical basis and scientific guidance for optimizing rigid and flexible object hybrid layouts and methane explosion protection technology in urban underground spaces.
基金supported by the German Academic Scholarship Foundation,the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation,Project number 422117092)the Saxon Ministry of Science and Arts.
文摘Geo-monitoring provides quantitative and reliable information to identify hazards and adopt appropriate measures timely.However,this task inherently exposes monitoring staff to hazardous environments,especially in underground settings.Since 2000s,robots have been widely applied in various fields and many studies have focused on establishing autonomous mobile robotic systems as well as solving the issue of underground navigation and mapping.However,only a few studies have conducted quantitative evaluations of these methods,and almost none have provided a systematic and comprehensive assessment of the suitability of mapping robots for underground geo-monitoring.In this study,a methodology for objective and quantitative assessment of the applicability of SLAM methods in underground geo-monitoring is proposed.This involves the development of an underground test field and some specific metrics,which allow detailed local accuracy analysis of point measurements,line segments,and areas using artificial targets.With this proposed methodology,a series of repeated experimental measurements has been performed with an autonomous driving robot and the selected LiDAR-and visual-based SLAM methods.The resulting point cloud was compared with the reference data measured by a total station and a terrestrial laser scanner.The accuracy and precision of the selected SLAM methods as well as the verifiability and reliability of the results are evaluated and discussed by analysing quantities such as the deviations of the control points coordinates,cloudto-cloud distances between the test and reference point cloud,normal vector,centre point coordinates and area of the planar objects.The results demonstrate that the HDL Graph SLAM achieves satisfactory precision,accuracy,and repeatability with a mean cloud-to-cloud distance of 0.12 m(with a standard deviation of 0.13 m)in an 80 m closed-loop measurement area.Although RTAB-Map exhibits better plane-capturing capabilities,the measurement results reveal instability and inaccuracies.
基金supported by Young Scholar Program(Category A Continuation Funding)of National Natural Science Foundation of China(No.52525401)General Program of National Natural Science Foundation of China(No.52174125)+4 种基金Outstanding Youth Cultivation Project in Shanxi Province(No.202103021222008)Major Program of National Natural Science Foundation of China(No.52334005)New Cornerstone Science Foundation through the XPLORER PRIZEShanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SX-TD010)Shanxi Science and Technology Major Project(No.20201102004).
文摘Coal pillars are critical supporting structures between underground coal gasification gasifiers.Its bearing capacity and structural stability are severely threatened by high-temperature environments.To elucidate the high-temperature deterioration mechanism of coal pillars at multiple scales,coal strength features as a function of temperature were investigated via uniaxial compression and acoustic emission equipment.The pyrolysis reaction process and microstructure evolution were characterized via X-ray diffractometer(XRD),scanning electron microscope(SEM),thermogravimetric(TG),Fourier transform infrared spectroscopy(FTIR),and computed tomography(CT)tests.Experimental results reveal a critical temperature threshold of 500℃for severe degradation of the coal bearing capacity.Specifically,both the strength and elastic modulus exhibit accelerated degradation above this temperature,with maximum reductions of 45.53%and 61.34%,respectively.Above 500℃,coal essentially undergoes a pyrolysis reaction under N_(2)and CO_(2)atmospheres.High temperatures decrease the quantity of O_(2)-based functional groups,growing aromaticity and the degree of graphitization.These changes induce dislocation and slip inside the coal crystal nucleus and then lead to deformation of the coal molecular structural units and strain energy generation.This process results in a great increase in porosity.Consequently,the stress deformation of coal increases,transforming the type of failure from brittle to ductile failure.These findings are expected to provide scientific support for UCG rock strata control.
基金Supported by Guizhou Provincial Key Technology R&D Program(No.2202023QKHZC).
文摘[Objectives]This study was conducted to investigate water pollution in the Huanghou Underground River Basin.[Methods]Five representative water quality indicators,ammonia nitrogen(NH+4-N),nitrate nitrogen(NO_(3)^(-)-N),permanganate index(COD Mn),total phosphorus(TP),and nitrite nitrogen(NO_(2)^(-)-N),were selected.The single-factor pollution index(P i),Nemerow pollution index(P N),and water quality index(WQI)were calculated to quantitatively assess pollution characteristics and evaluate water quality in the basin.[Results]The overall water quality in the Huanghou Underground River Basin fell within the"slightly polluted to good"range,with pollution primarily concentrated in the upstream areas.The downstream water quality was generally better,as most pollutants from the upstream were diluted or degraded during migration,resulting in little impact on the downstream areas.[Conclusions]This study provides a theoretical basis for understanding the pollution characteristics and evaluation of water quality in the Huanghou Underground River Basin.
基金supported by the National Natural Science Foundation of China(Project Approval Number:52404270)Postdoctoral Innovative Talent Support Program(BX20230427)+2 种基金Postdoctoral Surface Fund Grants(2023M743874)Research Start-up Fund of China University of Petroleum(Beijing)(2462023XKBH017)Fundamental Research Project Grant of China Academy of Safety Science and Technology(2023JBKY07)。
文摘Gas explosions are a frequent hazard in underground confined spaces in the process of urban development.Liquid sedimentary layers,commonly present in these environments,have not been sufficiently studied in terms of their impact on explosion dynamics.This study aims to investigate how gas-liquid two-phase environments in confined underground spaces affect the explosion characteristics of natural gas.To achieve this,experiments are conducted to examine the propagation of natural gas explosions in water and diesel layers,focusing on the influence of liquid properties and the liquid fullness degree(Lx)on explosion behavior.The results indicate that the presence of a liquid layer after the initial ignition stage significantly attenuates both the peak overpressure and the rise speed of pressure,in comparison to the natural gas conditions.During the subsequent explosive reaction,the evaporation and combustion of the diesel surface resulted in a distinct double-peak pressure rise profile in the diesel layer,with the second peak notably exceeding the first peak.Under conditions with a liquid sedimentary layer,the flame propagation velocities range from 6.53 to 34.1 m/s,while the overpressure peaks vary between 0.157 and 0.255 MPa.The explosion duration in both the water and diesel layer environments is approximately twice as long as that of the natural gas explosion,although the underlying mechanisms differ.In the diesel layer,the prolonged explosion time is attributed to the evaporation and combustion of the diesel,while in the water layer,the flame propagation velocity is significantly reduced.Under the experimental conditions,the maximum explosion energy reached 7.15×10~6J,corresponding to a TNT equivalent of 1.7.The peak overpressure surpassed the threshold for human fatality as defined by overpressure standards,posing a potential risk of damage to large steel-frame structures.The explosion shockwave in diesel layer conditions(L_(d)=0%,5%,7.5%,12.5%)and water layer(L_(w)=12.5%)conditions is observed to be sufficient to damage earthquake-resistant reinforced concrete.This study investigates the impact of sediment layer thickness and composition on gas explosions,and evaluates the associated explosion energy to assess human injuries and structural damage in underground environments.The findings of this study provide a scientific reference for urban underground safety.
基金supported by the Shenzhen Science and Technology Plan(JCYJ20190808123013260).
文摘Surface space constraints and the associated massive carbon emissions present significant challenges to the sustainable development of megacities.Urban underground space(UUS)construction is expected to provide a practical approach for alleviating the space constraints of surface construction.However,indepth examinations of the overall UUS system to reveal carbon emissions in the complex matrix are lacking.This study demonstrates the vital role of UUS development in achieving carbon neutrality using a streamlined life-cycle assessment method.Carbon emissions and the mitigation potential of building underground spaces,metro systems,and geothermal energy sources are analyzed.The construction of underground spaces in buildings is the largest carbon emitter within the entire UUS system,releasing a considerable 547.2 Mt in 2020.However,geothermal carbon sequestration,a significant element of the UUS system,provided an unexpected and impressive contribution,sequestering 170 Mt of carbon in 2020.This study shows that UUS addresses the lack of space for urban development and is a lowcarbon method of urban construction.Therefore,developing low-carbon building technologies and improving the UUS development model is imperative to achieving better low-carbon balance.This helps to promote more coordinated and sustainable urban development.
基金supported by the National Natural Science Foundation of China(Grant Nos.41972286 and 42102329).
文摘The Rock-soil interface is a common geological interface.Due to mechanical differences between soil and rock,the stress waves generated by underground blasting undergo intense polarization when crossing the rock-soil interface,making propagation laws difficult to predict.Currently,the characteristics of the impact of the rock-soil interface on blasting stress waves remain unclear.Therefore,the vibration field caused by cylindrical charge blasting in elastic rock and partial-saturation poro-viscoelastic soil was solved.A forward algorithm for the underground blasting vibration field in rock-soil sites was proposed,considering medium damping and geometric diffusion effects of stress waves.Further investigation into the influence of rock and soil parameters and blasting source parameters revealed the following conclusions:stress waves in soil exhibit dispersion,causing peak particle velocity(PPV)to display a discrete distribution.Soil parameters affect PPV attenuation only within the soil,while blasting source parameters affect PPV attenuation throughout the entire site.Multi-wave coupling effects induced by the rocksoil interface result in zones of enhanced and attenuated PPV within the site.The size of the enhancement zone is inversely correlated with the distance from the blasting source and positively correlated with the blasting source attenuation rate and burial depth,providing guidance for selecting explosives and blasting positions.Additionally,PPV attenuation rate increases with distance from the rock-soil interface,but an amplification effect occurs near the interface,most noticeable at 0.1 m.Thus,a sufficient safety distance from the rock-soil interface is necessary during underground blasting.
文摘The configuration of underground powerhouses is crucial in pumped-storage hydropower projects,which play a vital role in maintaining grid stability,facilitating the integration of renewable energy sources,and managing flood risks.However,geotechnical challenges,such as complex joint orientations,anisotropy in in-situ stress,and rock damage caused by excavation,require thorough stability assessments.This research employs the ubiquitous anisotropic joint model within FLAC3D to investigate the effects of joint dip angle,joint dip direction,and the alignment of in-situ stress on the stability of surrounding rock formations.The key parameters analyzed include joint cohesion,friction angle,and the magnitude of in-situ stress.The numerical results indicate that deformation is minimized when the axis of the powerhouse is aligned with the major principal stress.Furthermore,joint dip angles between 65°and 70°lead to a 50%reduction in both displacement and plastic zone volume.Additionally,angles less than 40°between the joint dip direction and the powerhouse axis enhance stability.These findings provide practical recommendations for optimizing the orientation of powerhouses in geomechanical contexts similar to those characterized by foliated sericite phyllite with moderate joint persistence.
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202401501,KJZD-M202401501).
文摘This work proposes an optimization method for gas storage operation parameters under multi-factor coupled constraints to improve the peak-shaving capacity of gas storage reservoirs while ensuring operational safety.Previous research primarily focused on integrating reservoir,wellbore,and surface facility constraints,often resulting in broad constraint ranges and slow model convergence.To solve this problem,the present study introduces additional constraints on maximum withdrawal rates by combining binomial deliverability equations with material balance equations for closed gas reservoirs,while considering extreme peak-shaving demands.This approach effectively narrows the constraint range.Subsequently,a collaborative optimization model with maximum gas production as the objective function is established,and the model employs a joint solution strategy combining genetic algorithms and numerical simulation techniques.Finally,this methodology was applied to optimize operational parameters for Gas Storage T.The results demonstrate:(1)The convergence of the model was achieved after 6 iterations,which significantly improved the convergence speed of the model;(2)The maximum working gas volume reached 11.605×10^(8) m^(3),which increased by 13.78%compared with the traditional optimization method;(3)This method greatly improves the operation safety and the ultimate peak load balancing capability.The research provides important technical support for the intelligent decision of injection and production parameters of gas storage and improving peak load balancing ability.
基金Project(2022YFC2905100)supported by the National Key Research and Development Program of ChinaProject(52174098)supported by the National Natural Science Foundation of China。
文摘With the continuous expansion of deep underground engineering and the growing demand for safety monitoring,microseismic monitoring has become a core method for early warning of rock mass fracture and engineering stability assessment.To address problems in existing methods,such as low data processing efficiency and poor phase recognition accuracy under low signal-to-noise ratio(SNR)conditions in complex geological environments,this study proposes an intelligent phase picking model based on ResUNet.The model integrates the residual learning mechanism of ResNet with the multi-scale feature extraction capability of UNet,effectively mitigating the vanishing gradient problem in deep networks.It also achieves cross-layer fusion of shallow detail features and deep semantic features through skip connections in the encoder-decoder structure.Compared with traditional short-time average/long-time average(STA/LTA)algorithms and advanced neural network models such as PhaseNet and EQTransformer,ResUNet shows superior performance in picking P-and S-wave phases.The model was trained on 400000 labeled microseismic signals from the Stanford earthquake dataset(STEAD)and was successfully applied to the Shizhuyuan polymetallic mine in Hunan Province,China.The results demonstrate that ResUNet achieves high picking accuracy and robustness in complex geological conditions,offering reliable technical support for early warning of disasters such as rockburst in deep underground engineering.
基金supported by the Moroccan Ministry of Higher Education,Scientific Research,and Innovationthe Moroccan Digital Development Agency(DDA)+2 种基金the National Center for Scientific and Technical Research of Morocco(CNRST)through the Al-Khawarizmi projectthe MANAGEM groupMASCIR supporting this project.
文摘Rockfalls are among the frequent hazards in underground mines worldwide,requiring effective methods for detecting unstable rock blocks to ensure miners’and equipment’s safety.This study proposes a novel approach for identifying potential rockfall zones using infrared thermal imaging and image segmentation techniques.Infrared images of rock blocks were captured at the Draa Sfar deep underground mine in Morocco using the FLUKE TI401 PRO thermal camera.Two segmentation methods were applied to locate the potential unstable areas:the classical thresholding and the K-means clustering model.The results show that while thresholding allows a binary distinction between stable and unstable areas,K-means clustering is more accurate,especially when using multiple clusters to show different risk levels.The close match between the clustering masks of unstable blocks and their corresponding visible light images further validated this.The findings confirm that thermal image segmentation can serve as an alternative method for predicting rockfalls and monitoring geotechnical issues in underground mines.Underground operators worldwide can apply this approach to monitor rock mass stability.However,further research is recommended to enhance these results,particularly through deep learning-based segmentation and object detection models.
