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Experimental and numerical investigations on the tensile mechanical behavior of marbles containing dynamic damage

International Journal of Mining Science and Technology 2022年第1期32卷 89-102页

作者： Tao Zhang Liyuan Yu Haijian Su Qiang Zhang Shaobo Chai State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China School of Civil Engineering Chang’an UniversityXi’an 710064China

To investigate the degradation mechanism of static tensile mechanical behaviors of marble containing dynamic damage,multiple impact loading tests were performed on the disc marble samples,and then static Brazilian tests were conducted for the damaged ***,coupling modeling technology of finite difference method(FDM)—discrete element method(DEM)was used to carry out the numerical *** results show that after multiple impacts,more white patches appear on the surface,and some microcracks,macro-fractures as well as pulverized grains are found by optical *** static tensile strength decreases with the increase of the dynamic damage variable characterized by the ultrasonic wave velocity of *** interaction between grains in the damaged sample becomes intense in the subsequent static loading process,causing a relatively large *** volume of the fragments falling off around the loading points becomes larger as impact number *** the dynamic damage increases,the absorbed energy of sample during the static loading first decreases and then tends to be *** the stress concentration and the breakage of the force chains are the root causes of the degradation of the static tensile strength.

关键词： Rock mechanics Tensile mechanical behavior Cumulative dynamic damage SHPB FDM-DEM coupling

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Deformation characteristics and novel strain criteria of strainbursts induced by low-frequency cyclic disturbance

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deep underground Science and engineering 2023年第1期2卷 52-60页

作者： Lihua Hu Minghe Ju Peng Zhao Xiaozhao Li State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouChina Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education School of Civil and Architecture EngineeringGuangxi UniversityNanningGuangxiChina

Strainbursts induced by cyclic disturbance with low frequency(termed as cyclicinduced strainbursts)are major dynamic disasters during deep excavation and *** is currently no quantitative criterion available for the prediction of such disastrous *** this study,based on true triaxial experiments,we analyzed the deformation characteristics,established two novel strain criteria for the cyclic-induced strainbursts,and explained the physical meaning of these *** strains for the cyclic-induced strainbursts were defined,including the control strain ε_(ctr),the strain caused by the combined dynamic and static loading ε_(sd),and the ultimate strain ε_(u) after *** indicated by the results,the deformation evolution of the cyclic-induced strainbursts shows remarkable fatigue characteristics,which resemble that of rock subjected to cyclic loading and *** other words,there are three stages during deformation evolution,namely,initial rapid growth,uniform velocity growth after several periods of disturbance,and sudden sharp growth preceding the *** ultimate strain ε_(u) is insensitive to the tangential static stress and disturbance amplitude,but it changes nonlinearly with disturbance *** the perspective of deformation,the occurrence of a cyclic-induced strainburst is controlled by the control strainε_(ctr).Thus,a control strain criterion is proposed;that is,when the stain ε_(sd) is larger than the control strain ε_(ctr),a strainburst will be induced by cyclic ***,based on the statistical results,a strain ratio criterion is proposed;that is,when the strain ratio ε_(sd)/ε_(u) is greater than 30%,a cyclic-induced strainburst will be induced.

关键词： dynamic disturbance low frequency strainbursts strain criteria true triaxial

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Fatigue characteristics of deep excavation-disturbed jinping marble

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Journal of Rock Mechanics and Geotechnical engineering 2025年第1期17卷 341-356页

作者： Anlin Zhang Ru Zhang Ting Ai Li Ren Zetian Zhang Jing Xie Chendi Lou Kun Xiao Zeqian Yang State Key Laboratory of Intelligent Construction&Healthy Operation&Maintenance of Deep Underground Engineering College of Water Resource&HydropowerSichuan UniversityChengdu 610065China Asian School of the Environment College of ScienceNanyang Technological University639798Singapore Key Laboratory of Deep Earth Science&Engineering Ministry of EducationSichuan UniversityChengdu 610065China State Key Laboratory of Hydraulics&Mountain River Engineering Sichuan UniversityChengdu 610065China Institute for Disaster Management&Reconstruction Sichuan UniversityChengdu 610065China

deep rocks encountered in underground engineering are frequently in complex in situ environments and experience both excavation disturbance during construction and cyclic loading throughout the long-term operation. Understanding the fatigue behavior of excavation-disturbed rocks in complex stress environments is critical for assessing the long-term stability of deep rock structures. Hence, an experimental method has been developed to capture the fatigue damage process of rocks while considering the in situ environment and excavation disturbance. Using this method, a series of triaxial fatigue damage experiments were conducted on Jinping deep marble samples from various in situ environments of 100 m, 1000 m, 1800 m, and 2400 m to better understand the variation in fatigue characteristics at different depths. With increasing depth, the samples experienced more cycles and greater fatigue deformation before failure. Further insights were gained into the fatigue damage behavior in terms of stiffness degradation, energy dissipation and irreversible strain accumulation. A decrease in the elastic modulus and an increase in the dissipated energy and irreversible strain exhibit an evolution pattern of initial→stabilization→acceleration, reflecting the nonlinear fatigue process that occurs inside marble. With increasing depth, marble samples have longer fatigue lives but exhibit more significant stiffness loss, energy dissipation and irrecoverable deformation accumulation;thus, evaluating the instability of deep rock structures solely using fatigue life alone is inadequate. Moreover, the previously reported inverted S-shaped evolution of fatigue damage was observed, and it was found that an increase in depth leads to an earlier onset of the accelerated fatigue damage stage with greater dominance of fatigue failure. Based on the nonlinear strain, loading cycle variable and fatigue life, a highly accurate nonlinear fatigue model was developed to describe the complete inverted S-

关键词： Excavation-disturbed rock In situ environment Fatigue behavior Damage model

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Mechanical properties and acoustic emission characteristics of soft rock with different water contents under dynamic disturbance

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International Journal of Coal Science & Technology 2024年第3期11卷 135-148页

作者： Yujing Jiang Lugen Chen Dong Wang Hengjie Luan Guangchao Zhang Ling Dong Bin Liang State Key Laboratory of Mining Disaster Prevention and Control Co-Founded By Shandong Province and the Ministry of Science and Technology Shandong University of Science and TechnologyQingdao266590China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyBeijing100083China Inner Mongolia Shanghaimiao Mining Co. Ltd.Ordos016299China

Uniaxial compression tests and cyclic loading acoustic emission tests were conducted on 20%,40%,60%,80%,dry and saturated muddy sandstone by using a creep impact loading system to investigate the mechanical properties and acoustic emission characteristics of soft rocks with different water contents under dynamic *** mechanical properties and acoustic emission characteristics of muddy sandstones at different water contents were *** of experimental studies show that water is a key factor in the mechanical properties of rocks,softening them,increasing their porosity,reducing their brittleness and increasing their *** uniaxial compression,the macroscopic damage characteristics of the muddy sandstone change from mono-bevel shear damage and‘X’type conjugate bevel shear damage to a roadway bottom-drum type damage as the water content *** perturbation has a strengthening effect on the mechanical properties of samples with 60%and less water content,and a weakening effect on samples with 80%and more water content,but the weakening effect is not *** damage characteristics of dry samples remain unchanged,water samples from shear damage and tensile–shear composite damage gradually transformed into cleavage damage,until saturation transformation monoclinic shear *** evolution of acoustic emission energy and event number is mainly divided into four stages:loading stage(Ⅰ),dynamic loading stage(Ⅱ),yield failure stage(Ⅲ),and post-peak stage(Ⅳ),the acoustic emission characteristics of the stages were different for different water *** characteristic value of acoustic emission key point frequency gradually decreases,and the damage degree of the specimen increases,corresponding to low water content—high main frequency—low damage and high water content—low main frequency—high damage.

关键词： Dynamic disturbance Soft rock Cyclic loading Acoustic emission Water content

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Spatial and temporal variation process of seabed dynamic response induced by the internal solitary wave

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Acta Oceanologica Sinica 2023年第2期42卷 142-149页

作者： Zhuangcai Tian Lei Jia Naili Hu Susheng Wang Mingwei Zhang Guoqing Zhou State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China Key Laboratory of Coastal Science and Integrated Management Ministry of Natural ResourcesQingdao266061China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao266100China

Internal solitary wave(ISW)is often accompanied by huge energy transport,which will change the pore water pressure in the *** on the two-dimensional Biot consolidation theory,the excess pore water pressure in seabed was simulated,and the spatiotemporal distribution characteristics of excess pore water pressure was *** the parameters of both ISW and seabed can affect the excess pore water pressure,the distribution of pore water pressure showed both dissipation and phase *** parametric studies were done on these two *** to influenced by the phase lag of excess pore water pressure,the penetration depth under the site of northern South China Sea with total water depth 327 m,induced by typical internal solitary wave increased by 26.19%,53.27%and 149.86%from T_(0)to T_(0.5)in sand silt,clayey silt and fine sand seabed,*** means the effect of ISW on seabed will be underestimated if we only take into accout the penetration depth under ISW trough,especially for fine sand *** addition,the concept of“amplitude-depth ratio”had been introduced to describe the influence of ISW on seabed dynamic response in the actual marine *** present study,it is negatively correlated with the excess pore water pressure,and an ISW with smaller amplitude-depth ratio can wide the range of lateral *** study results help understand the seabed damage induced by the interaction between ISW and seabed.

关键词： internal solitary wave pore water pressure seabed dynamic response variation process

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Effects of intermediate stress on deep rock strainbursts under true triaxial stresses

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Journal of Rock Mechanics and Geotechnical engineering 2023年第3期15卷 659-682页

作者： Lihua Hu Liyuan Yu Minghe Ju Xiaozhao Li Chun’an Tang State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China Sate Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian116024China Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education School of Civil and Architecture EngineeringGuangxi UniversityNanning530004China

The effect of intermediate stress(in situ tunnel axial)on a strainburst is studied with a threedimensional(3D)bonded block distinct element method(DEM).A series of simulations of strainbursts under true triaxial in situ stress conditions(*** tangential stress,moderate intermediate stress and low radial stress)of near-boundary rock masses are *** with the experimental results,the DEM model is able to capture the stress-strain response,failure pattern and energy balance of *** fracturing processes of strainbursts are also numerically *** results show that,as the intermediate stress increases:(1)The peak strain of strainbursts increases,the yield stress increases,the rock strength increases linearly,and the ratio of yield stress to rock strength decreases,indicating that the precursory information on strainbursts is enhanced;(2)Tensile and shear cracks increase significantly,and slabbing and bending of rock plates are more pronounced;and(3)The stored elastic strain energy and dissipated energy increase linearly,whereas the kinetic energy of the ejected rock fragments increases approximately exponentially,implying an increase in strainburst *** comparing the experimental and numerical results,the effect of intermediate stress on the rock strength of strainbursts is discussed in order to address three key ***,the Mogi criterion is applied to construct new strength criteria for strainbursts by converting the one-face free true triaxial stress state of a strainburst to its equivalent true triaxial stress *** summary,the effect of intermediate stress on strainbursts is a double-edged sword that can enhance the rock strength and the precursory information of a strainburst,but also increase its intensity.

关键词： Strainbursts Intermediate stress Distinct element method(DEM) Structural failure True triaxial Strength criterion

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Evaluation on cutting performance of novel PDC cutter for pipe jacking machine

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underground Space 2024年第1期14卷 34-52页

作者： Long-Chuan Deng Yi-Xiang Yuan Xiao-Zhao Li Qian-Wei Zhuang Chi Zhang Yi-Wei Chen School of Earth Sciences and Engineering Nanjing UniversityNanjingJiangsu 210023China Shanghai Tunnel Engineering Co.Ltd. Shanghai 200232China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouJiangsu 221116China School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China

It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated *** previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this *** on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut *** peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel *** LS-DYNA is employed to investigate the cutting performance in *** simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel ***,the linear cutting platform is adopted to investigate the force ability and damage state of PDC *** is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse *** patterns occurred in both numerical and experimental results are generally ***,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 *** tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC *** is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.

关键词： PDC cutter RC Pipe jacking machine Linear cutting tests Damage and wear LS-DYNA

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Shear failure behaviors and degradation mechanical model of rockmass under true triaxial multi-level loading and unloading shear tests

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International Journal of Mining Science and Technology 2024年第10期34卷 1385-1408页

作者： Zhi Zheng Ronghua Li Pengzhi Pan Jinghua Qid Guoshao Su Hong Zheng State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China China Energy Engineering Group Guangxi Electric Power Design Institute Co.Ltd. Nanning 530007China State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

The redistribution of three-dimensional(3D)geostress during underground tunnel excavation can easily induce to shear failure along rockmass structural plane,potentially resulting in engineering ***,the current understanding of rockmass shear behavior is mainly based on shear tests under2D stress without lateral stress,the shear fracture under 3D stress is unclear,and the relevant 3D shear fracture theory research is ***,this study conducted true triaxial cyclic loading and unloading shear tests on intact and bedded limestone under different normal stress σ_(n) and lateral stressσ_(p)to investigate the shear strength,deformation,and failure *** results indicate that under differentσ_(n)and σ_(p),the stress–strain hysteresis loop area gradually increases from nearly zero in the pre-peak stage,becomes most significant in the post-peak stage,and then becomes very small in the residual stage as the number of shear test cycles *** shear peak strength and failure surface roughness almost linearly increase with the increase inσ_(n),while they first increase and then gradually decrease asσ_(p)increases,with the maximum increases of 12.9%for strength and 15.1%for *** shear residual strength almost linearly increases withσ_(n),but shows no significant change withσ_(p).Based on the acoustic emission characteristic parameters during the test process,the shear fracture process and microscopic failure mechanism were *** the shear stressτincreases,the acoustic emission activity,main frequency,and amplitude gradually increase,showing a significant rise during the cycle near the peak strength,while remaining almost unchanged in the residual *** true triaxial shear fracture process presents tensile-shear mixture failure characteristics dominated by microscopic tensile *** on the test results,a 3D shear strength criterion considering the lateral stress effect was proposed,and the determination met

关键词： True triaxial shear test Lateral stress effect Acoustic emission monitoring Shear parameters evolution Shear degradation mechanical model

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Impact of seepage flow on sediment resuspension by internal solitary waves:parameterization and mechanism

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Journal of Oceanology and Limnology 2023年第2期41卷 444-457页

作者： Zhuangcai TIAN Chao LIU Ziyin REN Xiujun GUO Mingwei ZHANG Xiuhai WANG Lei SONG Yonggang JIA State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Coastal Science and Integrated Management Ministry of Natural ResourcesQingdao 266061China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China

Sediment incipient motion is the first step in sediment *** studies ignored the effect of seepage flow on the mobility of sediment particles and simplified the seabed surface as a rigid boundary.A flume experiment was designed to innovatively divide the seabed into two parts to control the dynamic response of the seabed and control the seepage *** the experiment,the seabed sediments and the amplitude of internal solitary waves(ISWs)were changed to compare and analyze the impact of seepage flow on the sediment resuspension by shoaling ***,parametric research and verification were carried *** indicate that seepage flow can greatly influence fine sand,promote sediment resuspension,and increase the amount of suspension by two times on ***,seepage flow had a little effect on the suspension of clayey silt and sandy ***,seepage force was added to the traditional gravity,drag force,and uplift force,and the parameterization of threshold starting shear stress of coarse-grained sediments was *** results of this parameterization were verified,and seepage force was critical to *** threshold starting shear stress was reduced by 54.6%after increasing the seepage *** physical mechanism of this process corresponded to the vertical reciprocating transient seepage in and out the seabed interface caused by the wave-induced transient excess pore water *** quantitative study on seepage flow for shear stress of coarse-grained sediments induced by ISWs is critical to geohazard assessment.

关键词： internal waves seepage flow sediment resuspension parameterization mechanism

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Settlement Mode Analysis for An Immersed Tube Tunnel Considering A Nonuniform Foundation Under Tidal Load

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China Ocean engineering 2022年第3期36卷 427-438页

作者： WANG Yan-ning ZHOU Huan-zhu WANG Le-chen Department of Civil and Environmental Engineering Shantou UniversityShantou 515063China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221000China

Immersed tube tunnels are usually placed on soft soil layers in cross-sea tunnelling *** to the influence of stratum conditions and slope design,the longitudinal distribution of substratum layers is generally ***,the inhomogeneous deformation of the element-joint becomes the key factor in the failure of the immersed tube ***,a corresponding calculation method for joint deformation is needed to explore the deformation law of immersed tube *** constructing a three-section immersed tube tunnel analysis model(TTM),the relationship between the two types of deformation of the immersed tube tunnel structure in a longitudinal nonuniform soft soil foundation is described,and the deformation characteristics of the immersed structure under different boundaries are *** on the mechanical behaviour of the joint and foundation,according to the Timoshenko beam on the Vlasov two-parameter foundation(VTM),considering the tidal cyclic load during the operation and maintenance period,an example analysis is ***,the deformation characteristics and development trend of the immersed tube tunnel under the influence of different soil layers are *** obtained results have a certain guiding significance for the deformation calculation of immersed tube tunnels.

关键词： geotechnical engineering immersed tube tunnel theoretical analysis soft soil foundation element-soil interaction

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