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Mechanical response features and failure process of soft surrounding rock around deeply buried three-centered arch tunnel

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Journal of Central South University 2015年第10期22卷 4064-4073页

作者：赵瑜张志刚 Key Laboratory of New Technology for Construction of Cities in Mountain Area of Ministry of Education (Chongqing University) School of Civil Engineering Chongqing University National Key Laboratory of Gas Disaster Detecting Preventing and Emergency Controlling China Coal Technology Engineering Group Chongqing Research Institute

Due to the extreme complexity of mechanical response of soft surrounding rock(SR) around a tunnel under high geostatic stress conditions, the integration of physical and numerical modeling techniques was adopted. Based on the similarity theory, new composite-similar material was developed, which showed good agreement with the similarity relation and successfully simulated physico-mechanical properties(PMP) of deep buried soft rock. And the 800 mm×800 mm×200 mm physical model(PM) was conducted, in which the endoscopic camera technique was adopted to track the entire process of failure of the model all the time. The experimental results indicate that the deformation of SR around a underground cavern possessed the characteristics of development by stages and in delay, and the initial damage of SR could induce rapid failure in the later stage, and the whole process could be divided into three stages, including the localized extension of crack(the horizontal load(HL) was in the range of 130 k N to 170 k N, the vertical load(VL) was in the range of 119 k N to 153.8 k N), rapid crack coalescence(the HL was in the range of 170 k N to 210 k N, the VL was in the range of 153.8 k N to 182.5 k N) and residual strength(the HL was greater than 210 k N, the VL was greater than 182.5 k N). Under the high stress conditions, the phenomenon of deformation localization in the SR became serious and different space positions show different deformation characteristics. In order to further explore the deformation localization and progressive failure phenomenon of soft SR around the deeply buried tunnel, applying the analysis software of FLAC3 D three-dimensional explicit finite-difference method, based on the composite strain-softening model of Mohr-Coulomb shear failure and tensile failure, the calculation method of large deformation was adopted. Then, the comparative analysis between the PM experiment and numerical simulation of the three centered arch tunnels was implemented and the rel

关键词： deeply buried tunnel physical model(PM) surrounding rock(SR) failure process

Numerical modeling of the failure process of the heterogeneous karst rock mass using the DDA-SPH method

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Underground Space 2023年第6期13卷 1-22页

作者： Jingyao Gao Guangqi Chen Zhijie Wang Liping Li Yasuhiro Mitani Changze Li Hongyun Fan Xinyan Peng Yifan Jiang Department of Civil and Structural Engineering Kyushu UniversityFukuoka 819-0395Japan School of Civil and Transportation Engineering Hebei University of TechnologyTianjin 300401China Key Laboratory of Transportation Tunnel Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 610065China School of Qilu Transportation Shandong UniversityJinanShandong 250000China MOE Key Laboratory of Deep Earth Science and Engineering Institute for Disaster Management and ReconstructionSichuan UniversityChengdu 610031China

The sanding process caused by karstification in dolomite creates a special sandy dolomite stratum,where the frequent catastrophic instability of the surrounding rock occurred during tunnel *** this study,the micro-origin and macro-performance of the sandy dolomite stratum are first ***,a numerical model based on the coupling method between the discontinuous deformation analysis and smoothed particle hydrodynamics is proposed to depict the heterogeneous dolomite formation with different sanding ***,the mechanical behaviors of the heterogeneous dolomite samples under uniaxial compression are studied after calibrating the numerical parameters with the two single materials sampled from the tunnel site ***,the instability disasters of the dolomite surrounding rock with different sanding degrees are reproduced,and the failure behaviors of tunnels are explained with respect to the stress distribution and plastic *** obtained results show that the rotation and dislocation of the remained dolomite block contribute to the unsmooth stress–strain curve and deterioration in uniaxial compressive ***,the block serves as the skeleton in the transmission of field stress in underground space,which improves the stability of the formation.

关键词： Karst sanding effect DDA-SPH method Uniaxial compressive test Tunnel excavation failure process

Numerical analysis of tunnel reinforcing influences on failure process of surrounding rock under explosive stress waves

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Journal of Central South University of Technology 2008年第5期15卷 632-638页

作者：左宇军唐春安朱万成李地元李术才 Research Center for Numerical Test of Material failure Dalian University Center for Rock Instability and Seismicity Research Northeastern University Shenyang 110004 China School of Civil and Hydraulic Engineering Dalian University of TechnologyDalian 116024 China Center for Rock Instability and Seismicity Research Northeastern UniversityShenyang 110004 China School of Resources and Safety Engineering Central South UniversityChangsha 410083 China Geotechnical and Structural Engineering Research Center Shandong UniversityJinan 250061 China

Based on mesoscopic damage mechanics, numerical code RFPA2D （dynamic edition） was developed to analyze the influence of tunnel reinforcing on failure process of surrounding rock under explosive stress waves. The results show that the propagation phenomenon of stress wave in the surrounding rock of tunnel and the failure process of surrounding rock under explosive stress waves are reproduced realistically by using numerical code RFPA2O; from the failure process of surrounding rock, the place at which surrounding rock fractures is transferred because of tunnel reinforcing, and the rockfall and collapse caused by failure of surrounding rock are restrained by tunnel reinforcing; furthermore, the absolute values of peak values of major principal stress, and the minimal principal stress and shear stress at center point of tunnel roof are reduced because of tunnel reinforcing, and the displacement at center point of runnel roof is reduced as well, consequently the stability of tunnel increases.

关键词： tunnel reinforcing numerical simulation explosive stress wave failure process inhomogeneity

Numerical Simulation on failure process in Brittle and Heterogeneous Matrix Filled with Randomly Distributed Particles

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Journal of Wuhan University of Technology(Materials Science) 2006年第2期21卷 150-153页

作者：张亚芳 School of Civil Engineering Guangzhou UniversityGuangzhou 510405ChinaSchool of Resource & Civil EngineeringNortheastern UniversityShenyang 110004China 3.Halcrow China 4/F Devon House979 King's Road Taikoo Place HongKong

Based on an essential assumption of meso-heterogeneity of material, the macro characteristic of composite reinfiorced with particles, the crack initiation, propagation and the failure process in composite were studied by using a numerical code. The composite is subjected to a uniaxial tension, aact stiff or soft particles are distributed at random manner but without overlapping or contacting. The effect of reinforcement particle properties on the fracture process aact mechanism of composite with brittle matrix, furthermore, the influence of the particle volumetric fraction is also investigated. Numerical results present the different failure mode and re-produce the crack initiation, propagation aurl coalescence in brittle aurl heterogeneons matrix. The mechanism of sach failure was also elucidated.

关键词： composite particle failure process numerical simulation

Impact failure of Flattened Brazilian Disc with Cracks——process and Mechanism

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Journal of Wuhan University of Technology(Materials Science) 2020年第5期35卷 1003-1010页

作者： ZHANG Yafang LIU Hao YIN Guoqi OU Chenggui LU Juan HE Juan School o f Civil Engineering Guangzhou UniversityGuangzhou 510006China Shenzhen Municipal Design Research Institute Co.Ltd. Shenzhen 518029China

Split Hopkinson pressure bar(SHPB)has been used to study the dynamic failure pattern of flattened mortar Brazilian disc under impact *** disc contains several prefabricated cracks paralleled to each *** FEM has also been adopted to simulate such failure *** mechanism of crack initiation,propagation and cut-through have been scrutinized with both experimental and numerical *** of the number of the prefabricated cracks on the specimen strength and acoustic emission(AE)performance can be observed and *** results show that the strength decreases and AE counts increases,when the number of the prefabricated cracks increases.

关键词： paralleled cracks flattened brazilian disc impact load SHPB failure process acoustic emission

Influence of Intersection Angle of Prefabricated Cracks on Impact failure of Flattened Brazilian Disc

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Journal of Wuhan University of Technology(Materials Science) 2021年第6期36卷 884-890页

作者： LIU Hao ZHANG Yafang YIN Guoqi OU Chenggui LU Juan HUO Yongjie Shenzhen Municipal Design Research Institute Co.Ltd Shenzhen 518029China School of Civil Engineering Guangzhou UniversityGuangzhou 510006China

Both experimental and numerical approaches were used to study dynamic failure properties and patterns of flattened Brazilian discs,containing two prefabricated cracks intersected at a varying *** of crack initiation,propagation,and cut-through were scrutinized and influences of the intersection angle on specimen strength and acoustic emission performance were also *** primary cracks initialize near the middle or the tip points of the upper prefabricated crack,and they continue to develop along the load direction and finally cut through the *** secondary cracks could be observed in directions almost horizontal or parallel to the directions of prefabricated ***,it is found that stress intensity factor reaches its maximum for specimen with intersection angle of 0 degree.

关键词： crack flattened brazilian disc impact load SHPB failure process acoustic emission

Catastrophic failure mechanism of rock masses system and earthquake prediction based on percolation theory

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Rock Mechanics Bulletin 2022年第1期1卷 119-125页

作者： Zhaoxing Lv Yangsheng Zhao Zijun Feng Key Laboratory of In-situ Property-improving Mining of Ministry of Education Taiyuan University of TechnologyTaiyuan030024China College of Mining Engineering Taiyuan University of TechnologyTaiyuan030024China

The failure of rocks is a complicated process as the mechanical properties of the rock are governed by loading history and cumulative *** geometric aspects of fractures,such as the size and shape of the fractures,the spatial distribution of the fracture networks,and the relations among these aspects also depend on the loads acting on rock *** general,the fractures are randomly generated in space which is difficult to be described using mathematical *** this paper,the failure processes of rock have been analyzed using the percolation *** results indicate that the failure process of rock is a transition from a stable state to an unstable *** phenomenon is essentially consistent with the phase transition in the percolation *** on this consistency,a theoretical model of percolation for earthquake prediction is proposed.A large number of seismic data provided strong evidence in support of the reliability and applicability of this model.

关键词： Rock mass system failure process Fracture Earthquake prediction Percolation theory

NUMERICAL SIMULATION ON TUNNEL DEFORMATION process AND FORMING MECHANISM OF SELF-ADJUSTMENT PRESSURE ARCH

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NUMERICAL SIMULATION ON TUNNEL DEFORMATION PROCESS AND FORMI...

Effects of loading waveforms on rock damage using particle simulation method

庆祝中国力学学会成立50周年暨中国力学学会学术大会’2007

作者： ZHANG Z~(*,+1)) TANG CA~(**,+) MA TH~(**) LI LC~* *(Center for Rock Instability and Seismicity Research,Northeastern University,Shenyang 110004,China) **(School of Civil and Hydraulic Engineering,Dalian University of Technology,Dalian 116024,China) +(Center for Material failure Modeling Research,Dalian University,Dalian 116622,China)

With the knowledge of heterogeneous characteristics of rock at mesoscopic level,a newly numerical analysis method,Rock failure process Analysis(RFPA) code is firstly introduced to evaluate surrounding rock stability,analyze tunnel deformation process,and describe pressure self-adjustment forming arch mechanism. The heterogeneity of surrounding rock,and displacement field of pressure arch are present to analyze stress

关键词： surrounding rock stability pressure arch numerical simulation fracture heterogeneity failure process

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Journal of Central South University 2018年第7期25卷 1755-1765页

作者： XIA Ming GONG Feng-qiang Hunan Key Laboratory of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan 411105China College of Civil Engineering and Mechanics Xiangtan UniversityXiangtan 411105China School of Resources and Safety Engineering Central South UniversityChangsha 410083China

The particle simulation method is used to study the effects of loading waveforms （i.e. square, sinusoidal and triangle waveforms） on rock damage at mesoscopic scale. Then some influencing factors on rock damage at the mesoscopic scale, such as loading frequency, stress amplitude, mean stress, confining pressure and loading sequence, are also investigated with sinusoidal waveform in detail. The related numerical results have demonstrated that： 1） the loading waveform has a certain effect on rock failure processes. The square waveform has the most damage within these waveforms, while the triangle waveform has less damage than sinusoidal waveform. In each cycle, the number of microscopic cracks increases in the loading stage, while it keeps nearly constant in the unloading stage. 2） The loading frequency, stress amplitude, mean stress, confining pressure and loading sequence have considerable effects on rock damage subjected to cyclic loading. The higher the loading frequency, stress amplitude and mean stress, the greater the damage the rock accumulated; in contrast, the lower the confining pressure, the greater the damage the rock has accumulated. 3） There is a threshold value of mean stress and stress amplitude, below which no further damage accumulated after the first few cycle loadings. 4） The high-to-low loading sequence has more damage than the low-to-high loading sequence, suggesting that the rock damage is loading-path dependent.

关键词： rock damage failure process crack initiation and propagation loading waveform cycle loading particle simulation method