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A coupled elasto-plastic-damage mechanical model for marble

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Science china(Technological sciences) 2011年第S1期54卷 228-234页

作者： ZHOU Hui 1,zhang Kai 2 & FENG XiaTing 1 1 state key laboratory of geomechanics and geotechnical engineering,institute of rock and soil mechanics,chinese academy of sciences,wuhan 43.071,china 2 state key laboratory for geomechanics and Deep Underground engineering,china University of Mining&Technology,Xuzhou 221008,china state key laboratory of geomechanics and geotechnical engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan China state key laboratory for geomechanics and Deep Underground engineering China University of Mining & Technology Xuzhou China

A profound understanding of the mechanical behaviors of marble is very important for the design and construction of deep diversion tunnels in Jinping II hydropower *** this paper,a coupled elasto-plastic-damage mechanical model is presented for Jinping ***,the experimental investigations on Jinping marble are ***,based on the framework of continuum damage and plastic theories,a general mechanical model is proposed to predict the mechanical responses of Jinping *** proposed model is used to simulate the triaxial compressive tests,and there is a general good agreement between experimental data and numerical predictions in a qualitative *** proposed model is able to capture the main features of Jinping marble observed in experiments,such as progressive yielding process,damage induced by plastic distortion,dilation,elastic degradation and stress sensitivity.

关键词： mechanical model damage elasto-plastic coupling marble

3D thermo-hydro-mechanical-migratory coupling model and FEM analyses for dual-porosity medium

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Science china(Technological sciences) 2010年第8期53卷 2172-2182页

作者： zhang YuJun 1&zhang WeiQing 2 1 state key laboratory of geomechanics and geotechnical engineering,institute of rock and soil mechanics, chinese academy of sciences,wuhan 43.071,china 2School of Civil engineering,Southwest Jiaotong University,Chengdu 610031,china state key laboratory of geomechanics and geotechnical engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan China School of Civil engineering Southwest Jiaotong University Chengdu China

One kind of 3D coupled thermo-hydro-mechanical-migratory model for saturated-unsaturated dual-porosity medium was established,in which the stress field and the temperature field are single,but the seepage field and the concentration field are double,and the influences of sets,spaces,angles,continuity ratios,stiffness of fractures on the constitutive relationship of the medium can be *** relative three-dimensional program of finite element method was also *** comparing with the existing computation example,reliability of the model and the program were *** a hypothetical nuclear waste repository as a calculation example,the radioactive nuclide leak was simulated numerically with both the rock mass and the buffer being unsaturated media,and the temperatures,negative pore pressures,flow velocities,nuclide concentrations and normal stresses in the rock mass were *** results showed that the temperatures,negative pore pressures and nuclide concentrations in the buffer all present nonlinear changes and distributions that even though the saturation degree in porosity is only about 1/9 of that in fracture,the flow velocity of underground water in fracture is about 6 times of that in porosity because the permeability coefficient of fracture is almost four orders higher than that of porosity,and that the regions of stress concentration occur at the vicinity of two sides of the boundary between buffer and disposal pit wall.

关键词： dual-porosity medium thermo-hydro-mechanical-migratory coupling three-dimensional model FEM analysis

Investigation of stress-induced progressive failure of mine pillars using a Voronoi grain-based breakable block model

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International Journal of Mining Science and Technology 2024年第5期34卷 713-729页

作者： Shili Qiu Shirui zhang Quan Jiang Shaojun Li Hao zhang Qiankuan wang state key laboratory of geomechanics and geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of chinese academy of sciences Beijing 100049China state key laboratory of Ocean engineering Shanghai Jiao Tong UniversityShanghai 200240China

The Voronoi grain-based breakable block model(VGBBM)based on the combined finite-discrete element method(FDEM)was proposed to explicitly characterize the failure mechanism and predict the deformation behavior of hard-rock mine *** influence of the microscopic parameters on the macroscopic mechanical behavior was investigated using laboratory-scale *** field-scale pillar models(width-to-height,W/H=1,2 and 3)were calibrated based on the empirically predicted stress-strain curves of Creighton mine *** results indicated that as the W/H ratios increased,the VGBBM effectively predicted the transition from strain-softening to pseudo-ductile behavior in pillars,and explicitly captured the separated rock slabs and the V-shaped damage zones on both sides of pillars and conjugate shear bands in core zones of *** volumetric strain field revealed significant compressional deformation in core zones of *** the peak strains of W/H=1 and 2 pillars were relatively consistent,there were significant differences in the strain energy storage and release mechanism.W/H was the primary factor influencing the deformation and strain energy in the pillar *** friction coefficient of the structural plane was also an important factor affecting the pillar strength and the weakest discontinuity *** fracture surface was controlled by the discontinuity angle and the friction *** study demonstrated the capability of the VGBBM in predicting the strengths and deformation behavior of hard-rock pillars in deep mine design.

关键词： Pillar strength FDEM Voronoi tessellation Spalling Bulking

Coupling effect of cement-stabilization and biopolymer-modification on the mechanical behavior of dredged sediment

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Journal of rock mechanics and geotechnical engineering 2024年第8期16卷 3284-3298页

作者： Lei Lang Jiangshan Li Xiao Huang Ping wang Wei zhang state key laboratory of geomechanics and geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China Hubei Provincial key laboratory of Contaminated Sludge and soil Science and engineering Wuhan430071China University of chinese academy of sciences Beijing100049China

Nowadays,biopolymer stabilization as a promising eco-friendly approach in soft ground improvement has attracted wide ***,the feasibility of using biopolymer as a green additive of cementstabilized dredged sediment(CDS)with high water content is still *** this study,guar gum(GG)and xanthan gum(XG)were adopted as typical biopolymers,and a series of unconfined compressive strength(UCS),splitting tensile strength(STS)and scanning electron microscopy(SEM)tests were performed to evaluate the mechanical and microstructural properties of XG-and GG-modified CDSs considering several factors including biopolymer modification,binderesoil ratio and wateresolid ***,the micro-mechanisms revealing the evolutions of mechanical properties of biopolymermodified CDS were *** results indicate that the addition of XG can effectively improve the strength of CDS,while the GG has a side *** XG content of 9%was recommended,which can improve the 7 d-and 28 d-UCSs by 196%and 51.8%,together with the 7 d-and 28 d-STSs by 118.3%and 42.2%,*** the binderesoil ratio or decreasing the wateresolid ratio significantly improved the strength gaining but aggravated the brittleness characteristics of *** XG to CDS contributed to the formation of microstructure with more compactness and higher cementation degrees of ordinary Portland cement(OPC)-XG-stabilized DS(CXDS).The micro-mechanism models revealing the interactions of multiple media including OPC cementation,biopolymer film bonding and bridging effects inside CXDS were *** key findings confirm the feasibility of XG modification as a green and high-efficiency mean for improving the mechanical properties of CDS.

关键词： Dredged sediment(DS) Stabilization Biopolymer modification Mechanical properties Micro-mechanism

Intermittent disturbance mechanical behavior and fractional deterioration mechanical model of rock under complex true triaxial stress paths

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International Journal of Mining Science and Technology 2024年第1期34卷 117-136页

作者： Zhi Zheng Hongyu Xu Kai zhang Guangliang Feng qiang zhang Yufei Zhao 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 state key laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100080China state key laboratory for geomechanics and Deep Underground engineering China University of Mining and TechnologyXuzhou 221116China

Mechanical excavation,blasting,adjacent rockburst and fracture slip that occur during mining excavation impose dynamic loads on the rock mass,leading to further fracture of damaged surrounding rock in three-dimensional high-stress and even causing ***,a novel complex true triaxial static-dynamic combined loading method reflecting underground excavation damage and then frequent intermittent disturbance failure is *** triaxial static compression and intermittent disturbance tests are carried out on *** effects of intermediate principal stress and amplitude on the strength characteristics,deformation characteristics,failure characteristics,and precursors of monzogabbro are analyzed,intermediate principal stress and amplitude increase monzogabbro strength and tensile fracture *** increases in microseismic parameters during rock loading can be precursors for intermittent rock *** on the experimental result,the new damage fractional elements and method with considering crack initiation stress and crack unstable stress as initiation and acceleration condition of intermittent disturbance irreversible deformation are proposed.A novel three-dimensional disturbance fractional deterioration model considering the intermediate principal stress effect and intermittent disturbance damage effect is established,and the model predicted results align well with the experimental *** sensitivity of stress states and model parameters is further explored,and the intermittent disturbance behaviors at different f are *** study provides valuable theoretical bases for the stability analysis of deep mining engineering under dynamic loads.

关键词： True triaxial static and disturbance test Mechanical properties Failure mechanism and precursor Intermittent disturbance effect Fractional mechanical model

Numerical simulation of crack propagation in three-point bending beams

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Numerical simulation of crack propagation in three-point ben...

rock strength weakening subject to principal stress rotation:Experimental and numerical investigations

The International Young Scholars’ Symposium on rock mechanics

作者： X.L.zhang Y.Y.Jiao state key laboratory of geomechanics and geotechnical engineering institute of rock and soil mechanics chinese academy of sciences wuhan china

＜正＞In recent years,there has been growing interest in numerical modeling of the crack propagation and failure process of brittle materials using mesoscopic *** this paper,at the meso-level,the process of crack propagation in three-point bending beam with a single pre-existing crack is numerically investigated by using a modified discontinuous deformation analysis（DDA）*** parameter as well as the distance of the pre-existing crack away from the mid axis of beam is studied to examine its influence on the crack growth *** the proposed method,some modifications,including the material heterogeneity,the artificial joint concept and the linear fracture mechanics have been embedded into the original DDA algorithm,enabling the DDA to perform crack growth *** crack growth path is obtained,and it is found that the crack initials from the pre-crack tip and grows to the position of loading *** stress field results show that the crack tip is always in tensile stress concentration state and as the crack increases,the stress concentration transfers to the new crack *** simulated results agree well with the existing physical and numerical results,and the laws of crack propagation are in accordance with the phenomena observed in tests.

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Journal of rock mechanics and geotechnical engineering 2024年第9期16卷 3544-3557页

作者： Huandui Liu Guibin wang Chunhe Yang Junyue zhang Shiwan Chen state key laboratory of geomechanics and geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of chinese academy of sciences Beijing100049China state key laboratory of Coal Mine Disaster Dynamics and Control College of Resources and Environmental SciencesChongqing UniversityChongqing400044China College of Resources and Environmental engineering Guizhou UniversityGuiyang50025China

During the construction and operation of gas storage reservoirs,changes in the principal stress direction can induce fracture propagation under conditions of lower differential stress,potentially leading to failure in the surrounding ***,the weakening of strength due to pure stress rotation has not yet been *** on fracture mechanics,an enhanced Mohr-Coulomb strength criterion considering stress rotation is proposed and verified with experimental and numerical *** micro-damage state and the evolution of the rock under the pure stress-rotation condition are *** findings indicate that differential stress exceeding the crack initiation stress is a prerequisite for stress rotation to promote the development of rock *** the differential stress increases,stress rotation is more likely to induce rock damage,leading to a transition from brittle to plastic failure,characterized by wider fractures and a more complex fracture ***,a negative exponential relationship exists between the stress rotation angle required for rock failure and the differential *** feasibility of applying the enhanced criterion to practical engineering is discussed using monitoring data obtained from a mine-by *** study introduces new concepts for understanding the damage evolution of the surrounding rock under complex stress paths and offers a new theoretical basis for predicting the damage of gas storage reservoirs.

关键词： Principal stress rotation(PSR) Fracture mechanics Hollow cylinder torsional apparatus for rock (HCAR) Particle flow method rock strength

Impact of mica on geotechnical behavior of weathered granitic soil using macro and micro investigations

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Journal of rock mechanics and geotechnical engineering 2024年第6期16卷 2250-2266页

作者： Xianwei zhang Xinyu Liu Haodong Gao Gang wang Ran An Zhu Liang state key laboratory of geomechanics and geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China School of Civil and Hydraulic engineering Huazhong University of Science and TechnologyWuhan430074China College of Urban Construction Wuhan University of Science and TechnologyWuhan430065China University of chinese academy of sciences Beijing100049China Guangzhou Urban Planning&Design Survey Research institute Guangzhou510000China Guangdong Enterprise key laboratory for Urban Sensing Monitoring and Early WarningGuangzhou510000China

The micaceous weathered granitic soil(WGS)is frequently encountered in civil engineering worldwide,unfortunately little information is available regarding how mica affects the physico-mechanical behaviors of *** study prepares reconstituted WGS with different mica contents by removing natural mica in theWGS,and then mixes it with commercial mica *** geotechnical behavior as well as the microstructures of the mixtures are *** addition of mica enables the physical indices of WGS to be specific combinations of coarser gradation and high permeability but high Atterberg ***,high mica content in WGS was found to be associated with undesirable mechanical properties,including increased compressibility,disintegration,and swelling potential,as well as poor compactability and low effective frictional *** analysis indicates that the influence of mica on the responses of mixtures originates from the intrinsic nature of mica as well as the particle packing being formed *** exists in the mixture as stacks of plates that form a spongy structure with high compressibility and swelling *** among the plates give the soil high water retention and high Atterberg *** pores are also generated by soil particles with bridging packing,which enhances the permeability and water-soil interactions upon *** study provides a microlevel understanding of how mica dominates the behavior of WGS and provides new insights into the effective stabilization and improvement of micaceous soils.

关键词： Weathered granitic soil(WGS) Mica Microstructure Physical properties Mechanical properties Mechanism

Failure mechanism and safety control technology of a composite strata roadway in deep and soft rock masses:a case study

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Journal of Mountain Science 2024年第7期21卷 2427-2444页

作者： ZHAO Chengwei ZHOU Hui SUN Xiaoming zhang Yong MIAO Chengyu wang Jian state key laboratory of geomechanics and geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of chinese academy of sciences Beijing 100049China state key laboratory for geomechanics and Deep Underground engineering China University of Mining and Technology(Beijing)Beijing 100083China School of mechanics and Civil engineering China University of Mining and Technology(Beijing)Beijing 100083China

The construction of coal mines often encounters deep composite soft rock roadways,which is characterized by significant deformation and poor *** deeply study the failure mechanism and large deformation challenges of a composite strata roadway in deep and soft rock masses,a numerical model of 3DEC tetrahedral blocks was established based on the method of rock quality designation(RQD).The results showed that original support cannot prevent asymmetric failure and large deformation due to the adverse geological environment and unsuitable support *** to the failure characteristics,a coupling support of“NPR bolt/cable+mesh+shotcrete+steel pipe”was proposed to control the stability of the surrounding *** excellent mechanical properties of large deformation(approximately 400 mm)and high constant resistance force(bolt with 180 k N;cable with 350 k N)were evaluated by the tensile *** numerical results showed that the maximum deformation was minimized to 243 mm,and the bearing capacity of the surrounding rock of the roadway was *** field test results showed that the maximum deformation of the surrounding rock was 210 mm,and the forces of the NPR bolt and cable were stable at approximately 180 k N and 350 k N,*** demonstrated the effectiveness of the coupling support with the NPR bolt and cable,which could be a guiding significance for the safety control of large deformation and failure in deep composite soft rock roadways.

关键词： 3DEC Composite strata roadway Soft rock NPR bolt and cable Asymmetric large deformation