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矿业科学技术学报(英文版)
矿业科学技术学报(英文版)

骆振福

双月刊

2095-2686

journal@cumt.edu.cn

0516-83885569

221008

江苏省徐州市中国矿业大学内

矿业科学技术学报(英文版)/Journal International Journal of Mining Science and TechnologyCSCDCSTPCD北大核心EISCI
正式出版
收录年代

    Estimation of the anisotropy of hydraulic conductivity through 3D fracture networks using the directional geological entropy

    Chuangbing ZhouZuyang YeChi YaoXincheng Fan...
    137-148页
    查看更多>>摘要:With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directional entropic scale is used to measure the anisotropy of spatial order in different directions.Compared with the traditional connectivity indexes based on the statistics of fracture geometry,the directional entropic scale is capable to quantify the anisotropy of connectivity and hydraulic conductivity in heterogeneous 3D fracture networks.According to the numerical analysis of directional entrogram and fluid flow in a number of the 3D fracture networks,the hydraulic conductivities and entropic scales in different directions both increase with spatial order(i.e.,trace length decreasing and spacing increasing)and are independent of the dip angle.As a result,the nonlinear correlation between the hydraulic con-ductivities and entropic scales from different directions can be unified as quadratic polynomial function,which can shed light on the anisotropic effect of spatial order and global entropy on the heterogeneous hydraulic behaviors.

    Experimental and numerical study on dynamic mechanical behaviors of shale under true triaxial compression at high strain rate

    Xiaoping ZhouLinyuan HanJing BiYundong Shou...
    149-165页
    查看更多>>摘要:High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic mechanical properties of shale.Dynamic experiments on shale subjected to true triaxial com-pression at different strain rates are first conducted in this research.The dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are investigated.The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate increases.The character-istics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression.Additionally,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of shale.The dynamic mechanical characteristics of shale subjected to dif-ferent confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method.The numerical results are in good agreement with the experimental data.

    Transfer learning framework for multi-scale crack type classification with sparse microseismic networks

    Arnold Yuxuan XieBing Q.Li
    167-178页
    查看更多>>摘要:Rock fracture mechanisms can be inferred from moment tensors(MT)inverted from microseismic events.However,MT can only be inverted for events whose waveforms are acquired across a network of sensors.This is limiting for underground mines where the microseismic stations often lack azimuthal coverage.Thus,there is a need for a method to invert fracture mechanisms using waveforms acquired by a sparse microseismic network.Here,we present a novel,multi-scale framework to classify whether a rock crack contracts or dilates based on a single waveform.The framework consists of a deep learning model that is initially trained on 2400000+manually labelled field-scale seismic and microseismic waveforms acquired across 692 stations.Transfer learning is then applied to fine-tune the model on 300000+MT-labelled lab-scale acoustic emission waveforms from 39 individual experiments instrumented with different sensor layouts,loading,and rock types in training.The optimal model achieves over 86%F-score on unseen waveforms at both the lab-and field-scale.This model outperforms existing empirical methods in clas-sification of rock fracture mechanisms monitored by a sparse microseismic network.This facilitates rapid assessment of,and early warning against,various rock engineering hazard such as induced earthquakes and rock bursts.

    Three-dimensional stress variation characteristics in deep hard rock of CJPL-Ⅱ project based on in-situ monitoring

    Minzong ZhengShaojun LiZejie FengHuaisheng Xu...
    179-195页
    查看更多>>摘要:In deep hard rock excavation,stress plays a pivotal role in inducing stress-controlled failure.While the impact of excavation-induced stress disturbance on rock failure and tunnel stability has undergone com-prehensive examination through laboratory tests and numerical simulations,its validation through in-situ stress tests remains unexplored.This study analyzes the three-dimensional stress changes in the sur-rounding rock at various depths,monitored during the excavation of B2 Lab in China Jinping Underground Laboratory Phase Ⅱ(CJPL-Ⅱ).The investigation delves into the three-dimensional stress variation characteristics in deep hard rock,encompassing stress components and principal stress.The results indicate changes in both the magnitude and direction of the principal stress during tunnel exca-vation.To quantitatively describe the degree of stress disturbance,a series of stress evaluation indexes are established based on the distances between stress tensors,including the stress disturbance index(SDI),the principal stress magnitude disturbance index(SDIm),and the principal stress direction distur-bance index(SDId).The SDI indicates the greatest stress disturbance in the surrounding rock is 4.5 m from the tunnel wall in B2 Lab.SDIm shows that the principal stress magnitude disturbance peaks at 2.5 m from the tunnel wall.SDId reveals that the largest change in principal stress direction does not nec-essarily occur near the tunnel wall but at a specific depth from it.The established relationship between SDI and the depth of the excavation damaged zone(EDZ)can serve as a criterion for determining the depth of the EDZ in deep hard rock engineering.Additionally,it provides a reference for future construc-tion and support considerations.

    Experimental study of the damage characteristics of rocks containing non-penetrating cracks under cyclic loading

    Jun XuXiaochun XiaoLu MaSen Luo...
    197-210页
    查看更多>>摘要:The damage evolution process of non-penetrating cracks often causes some unexpected engineering dis-asters.Gypsum specimens containing non-penetrating crack(s)are used to study the damage evolution and characteristics under cyclic loading.The results show that under cyclic loading,the relationship between the number of non-penetrating crack(s)and the characteristic parameters(cyclic number,peak stress,peak strain,failure stress,and failure strain)of the pre-cracked specimens can be represented by a decreasing linear function.The damage evolution equation is fitted by calibrating the accumulative plas-tic strain for each cycle,and the damage constitutive equation is proposed by the concept of effective stress.Additionally,non-penetrating cracks are more likely to cause uneven stress distribution,damage accumulation,and local failure of specimen.The local failure can change the stress distribution and relieve the inhibition of non-penetrating crack extension and eventually cause a dramatic destruction of the specimen.Therefore,the evolution process caused by non-penetrating cracks can be regarded as one of the important reasons for inducing rockburst.These results are expected to improve the under-standing of the process of spalling formation and rockburst and can be used to analyze the stability of rocks or rock structures.

    Predicting impact forces on pipelines from deep-sea fluidized slides:A comprehensive review of key factors

    Xingsen GuoNing FanDefeng ZhengCuiwei Fu...
    211-225页
    查看更多>>摘要:Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental protection.However,the place-ment of these pipelines on the seabed surface exposes them to potential risks arising from the complex deep-sea hydrodynamic and geological environment,particularly submarine slides.Historical incidents have highlighted the substantial damage to pipelines due to slides.Specifically,deep-sea fluidized slides(in a debris/mud flow or turbidity current physical state),characterized by high speed,pose a significant threat.Accurately assessing the impact forces exerted on pipelines by fluidized submarine slides is crucial for ensuring pipeline safety.This study aimed to provide a comprehensive overview of recent advance-ments in understanding pipeline impact forces caused by fluidized deep-sea slides,thereby identifying key factors and corresponding mechanisms that influence pipeline impact forces.These factors include the velocity,density,and shear behavior of deep-sea fluidized slides,as well as the geometry,stiffness,self-weight,and mechanical model of pipelines.Additionally,the interface contact conditions and spatial relations were examined within the context of deep-sea slides and their interactions with pipelines.Building upon a thorough review of these achievements,future directions were proposed for assessing and characterizing the key factors affecting slide impact loading on pipelines.A comprehensive under-standing of these results is essential for the sustainable development of deep-sea pipeline projects asso-ciated with seabed resource development and the implementation of disaster prevention measures.

    Pressure stimulated current in progressive failure process of combined coal-rock under uniaxial compression:Response and mechanism

    Tiancheng ShanZhonghui LiXin ZhangHaishan Jia...
    227-243页
    查看更多>>摘要:Effective monitoring of the structural health of combined coal-rock under complex geological conditions by pressure stimulated currents(PSCs)has great potential for the understanding of dynamic disasters in underground engineering.To reveal the effect of this way,the uniaxial compression experiments with PSC monitoring were conducted on three types of coal-rock combination samples with different strength combinations.The mechanism explanation of PSCs are investigated by resistivity test,atomic force microscopy(AFM)and computed tomography(CT)methods,and a PSC flow model based on progressive failure process is proposed.The influence of strength combinations on PSCs in the progressive failure pro-cess are emphasized.The results show the PSC responses between rock part,coal part and the two com-ponents are different,which are affected by multi-scale fracture characteristics and electrical properties.As the rock strength decreases,the progressive failure process changes obviously with the influence range of interface constraint effect decreasing,resulting in the different responses of PSC strength and direction in different parts to fracture behaviors.The PSC flow model is initially validated by the relation-ship between the accumulated charges of different parts.The results are expected to provide a new ref-erence and method for mining design and roadway quality assessment.

    Fatigue properties and damage constitutive model of salt rock based on CT scanning

    Junbao WangXiao LiuQiang ZhangXinrong Liu...
    245-259页
    查看更多>>摘要:To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,and the mesoscopic pore structures of salt rock before and after fatigue tests and under different cycle numbers were measured using CT scanning instrument.Based on the test results,the effects of the cycle number and the upper-limit stress on the evolution of cracks,pore morphology,pore number,pore volume,pore size,plane porosity,and volume porosity of salt rock were analyzed.The failure path of salt rock specimens under cyclic loading was analyzed using the distribution law of plane porosity.The damage variable of salt rock under cyclic loading was defined on basis of the variation of volume porosity with cycle number.In order to describe the fatigue deformation behavior of salt rock under cyclic loading,the nonlinear Burgers damage constitutive model was further established.The results show that the model established can better reflect the whole development process of fatigue deformation of salt rock under cyclic loading.

    Ash removal from inferior coal via ammonium fluoride roasting and simultaneous yield of white carbon black

    Xuqin DuanShuaiyu LuYuxiao FuJiazhe Zhang...
    261-279页
    查看更多>>摘要:The quality upgrading and deashing of inferior coal by chemical method still faces great challenges.The dangers of strong acid,strong alkali,waste water and exhaust gas as well as high cost limit its industrial production.This paper systematically investigates the ash reduction and desilicification of two typical inferior coal utilizing ammonium fluoride roasting method.Under the optimal conditions,for fat coal and gas coal,the deashing rates are 69.02%and 54.13%,and the desilicification rates are 92.64%and 90.27%,respectively.The molar dosage of ammonium fluoride remains consistent for both coals;how-ever,the gas coal,characterized by a lower ash and silica content(less than half that of the fat coal),achieves optimum deashing effect at a reduced time and temperature.The majority of silicon in coal transforms into gaseous ammonium fluorosilicate,subsequently preparing nanoscale amorphous silica with a purity of 99.90%through ammonia precipitation.Most of the fluorine in deashed coal are assigned in inorganic minerals,suggesting the possibility of further fluorine and ash removal via flotation.This research provides a green and facile route to deash inferior coal and produce nano-scale white carbon black simultaneously.