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Triaxial strength behaviour of rockmass satisfying Modified Mohr-Coulomb and Generalized Hoek-Brown criteria

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International Journal of Mining Science and Technology 2018年第6期28卷 901-915页

作者： Saurav Rukhaiyar Narendra Kumar Samadhiya Department of Civil Engineering Indian Institute of Technology Roorkee

The Triaxial strength of twenty rockmass types was predicted using two non-linear Triaxial strength criteria for rockmass i.e. Modified Mohr-Coulomb(MMC) criterion and Generalized Hoek-Brown(GHB)criterion. Four different rockmass classification systems were used for the calculation of MMC criterion parameters while only GSI classification system has been used for calculation of GHB parameters. The representative value of the uniaxial compressive strength and elastic modulus of rockmass have been estimated using probabilistic approach. A hypothetical case of an unsupported tunnel has been analyzed considering both MMC and GHB criteria. The analysis was done using the convergence-confinement method with two different approaches. The first approach predicts the tunnel response using GHB criterion directly. The second approach predicts the tunnel response using equivalent Mohr-Coulomb parameters obtained by linearization of Triaxial data points obtained from MMC and GHB criteria. The tunnel response has been estimated in terms of radius of plastic zone, tunnel convergence and tunnel convergence strain. For very poor rockmasses the tunnel response predicted by MMC criterion is less than that predicted by GHB criterion. For poor and fair rockmass, the tunnel response estimated considering both the criteria are comparable except for few cases. Squeezing condition in rockmass has been also evaluated.

关键词： Triaxial strength Modified Mohr-Coulomb criterion Generalised Hoek-Brown criterion Convergence-confinement method

Rockburst characteristics of several hard brittle rocks:A true Triaxial experimental study

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第2期12卷 279-296页

作者： Shaobin Zhai Guoshao Su Shunde Yin Bin Zhao Liubin Yan Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education School of Civil and Architecture EngineeringGuangxi UniversityNanning530004China Department of Civil and Environmental Engineering University of WaterlooWaterlooON N2L 3G1Canada State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China

Rockburst is a typical rock failure which frequently threatens both human life and construction equipment during highly stressed underground excavation.Rock lithology is a control factor of rockburst.In this paper,rockburst tests were conducted on rectangular prismatic specimens of six types of intact hard brittle rocks,i.***.granodiorite,granite,marble,basalt,sandstone and limestone,under one-free-face true Triaxial loading conditions.With the use of high-speed cameras,an acoustic emission(AE)system and a scanning electron microscope(SEM),rockburst of different rocks was investigated.The results show that the strainbursts of granodiorite,granite and marble were accompanied by tensile splitting near the free face,and consequently were relatively strong with a large amount of fragment ejection and kinetic energy release.For basalt,sandstone and limestone,failure was primarily dominated by shear rupture.The strainbursts of basalt and sandstone were relatively small with minor fragment ejection and kinetic energy release;while no burst failure occurred on limestone due to its relatively low peak strength.Rock strength,fracturing and fragmentation characteristics,and failure modes of different rocks can significantly affect rockburst proneness and magnitude.The AE evolution coupled with SEM analysis reveals that the differences in the inhe rent microstructures and fracture evolution under loading are the primary factors accounting for different rockbursts in various rock types.

关键词： Rockburst Strainburst Hard brittle rocks True Triaxial test Acoustic emission(AE)

Numerical solutions of rotational normal modes of a Triaxial two-layered anelastic Earth

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Geodesy and Geodynamics 2019年第2期10卷 118-129页

作者： Wenbin Shen Zhuo Yang Zhiliang Guo Wenying Zhang Department of Geophysics School of Geodesy and Geomatics/Key Laboratory of Geospace Environment and Geodesy of Ministry of EducationWuhan University State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan University

The Earth's rotational normal modes depend on Earth model used, including the layer structures,principal inertia moments of different layers and the compliances. This study focuses on providing numerical solution of the rotational normal modes of a Triaxial two-layered anelastic Earth model without external forces but with considering the complex forms of compliances and the electromagnetic coupling between the core and mantle. Based on the present knowledge of the Chandler wobble(CW) and Free Core Nutation(FCN), we provide a set of complete compliances which could be used for reference in further investigations. There are eight rotational normal mode solutions, four of which might exist in nature. However, in reality only two of these four solutions correspond to the present motion status of the prograde CW and the retrograde FCN. On one hand, our numerical calculations show that the periods and quality factors(Qs) of CW and FCN are respectively 434.90 and 429.86 mean solar days(d) and 76.56 and 23988.47 under frequency-dependent assumption, and the Triaxiality prolongs CW about 0.01 d and has hardly effect on FCN. On the other hand, we analyze the sensibility of compliances and electromagnetic coupling parameter on the periods and Qs of CW and FCN and find the sensitive parameters with respect to them.

关键词： Earth rotation Triaxial two-layered anelastic Earth model Compliances Rotational normal modes Numerical solution

Mechanical property of artificial methane hydrate under Triaxial compression

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Journal of Natural Gas Chemistry 2010年第3期19卷 246-250页

作者： Yongchen Song Feng Yu Yanghui Li Weiguo Liu Jiafei Zhao Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian 116024 Liaoning China

Methane production from hydrate reservoir may induce seabed slide and deformation of the hydrate-bearing strata.The research on mechanical properties of methane hydrate is considered to be important for developing an efficient methane exploitation technology.In this paper,a Triaxial test system containing a pressure crystal device was developed with the conditions to stabilize the hydrate.A series of Triaxial shear tests were carried out on artificial methane hydrate specimen.In addition,mechanical characteristics of methane hydrate were studied with the strain rates of 0.1 and 1.0 mm/min,respectively,under the conditions of different temperatures（T =-5,-10,and-20 ℃） and confining pressures（P = 0,5,10,15,and 20 MPa）.The preliminary results show that when the confining pressure was less than 10 MPa,the increase of confining pressure leaded to the enhancement of shear strength.Furthermore,the decreasing temperature and the increasing strain rate both caused the increase in shear strength.

关键词： Triaxial mechanical properties confining pressure temperature strain rate

Triaxial high-gaccelerometer of microelectro mechanical systems

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Journal of Beijing Institute of Technology 2015年第4期24卷 427-431页

作者：何昫张振海李科杰林然 School of Mechatronical Engineering Beijing Institute of Technology

A Triaxial high-g accelerometer of microelectro mechanical systems （MEMS） has a struc- ture of multi-chips combination and will be used in aerospace field, civil and military fields. The ac- celerometer can measure the acceleration of the carrier. The chips with island-membrane structures on its back surfaces are made by MEMS dry processing. The chip is reasonable and can work well under high impact load; Titanium alloy base is also stronger in high shock environment, these are proved by finite element analysis. Finally, the MEMS combined Triaxial high-g accelerometer is vali- dated by high impact calibration experiments in order to get a key performance index, including range, sensitivity and transverse sensitivity and so on. These data can satisfy the need of design but some problems remain, these will be eliminated by improvement of the processing technology and materials.

关键词： combined finite element analysis Triaxial high-g accelerometer

A tentative method for assigning the configuration of a Triaxial nuclei in TRS

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Chinese Physics C 2012年第9期36卷 827-830页

作者：李晓伟陆景彬于少英白洪波沈彩万 College of Physics Jilin University College of Physics and Electronic Information Engineering Chifeng University School of Science Huzhou Teachers College

A tentative method based on the principle of minimum energy is put forward for assigning the reasonable configuration of a Triaxial nucleus in TRS. This method is proved by the TSD of 167Lu nucleus that has been calcu... 详细信息

关键词： configuration Triaxial quasiparticle signature

Acoustic emission from gas-filled coal under Triaxial compression

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International Journal of Mining Science and Technology 2012年第6期22卷 775-778页

作者： Yin Guangzhi Qin Hu Huang Gun Lv Youchang Dai Zhixu State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University State and Local Joint Engineering Laboratory of Methane Drainage in Complex Coal Gas Seam Chongqing University College of Resource and Environmental Sciences Chongqing University Gas Research Institute Energy and Chemical Research InstituteZhongping Energy and Chemical Group

Acoustic emission(AE) experiments have been performed on gas-saturated coal specimens under conventional Triaxial compression.The AE characteristics were investigated for a methane gas flow through the coal specimen.One AE parameter,AE count,when normalized by the total count number was used to represent the damage evolution in the gassy coal.It is shown that this AE parameter is a reasonable indicator for damage occurring within the coal specimen since its envelope has almost the same shape as the complete stress-strain curve,except for a short time delay.In addition,the change in AE count is highly consistent with the change in coal permeability.Test results also show that methane containing coal emits a small number of AE events before entering the yield stage.AE activity gradually increases during the yield process up to the peak stress.The lowest permeability corresponds to the highest AE activity,implying failure will soon occur.An AE based constitutive model was constructed and the theoretical results agree well with those of experiments.

关键词： Rock mechanics Conventional Triaxial compression Failure process Permeability Acoustic emission

Study on the Constitutive Model of Marble Based on the Conventional Triaxial Compression Test

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上海交通大学学报 2004年第z2期38卷 8-13页

作者： Tian Sheng-li Lu Yun-de Ge Xiu-run School of Civil Engineering and Mechanics Shanghai Jiaotong University Shanghai200240China School of Civil Engineering and Mechanics Shanghai Jiaotong University Shanghai200240China School of Civil Engineering and Mechanics Shanghai Jiaotong University Shanghai200240China Institute of Rock and Soil Mechanics The Chinese Academy of Sciences Wuhan430071 China

The RMB-150B rock mechanics test system was employed to obtain the complete stress-strain test curves under confining pressures of 0-30MPa for marble samples from Ya'an ,Sichuan province. On the basis of former study and the convention Triaxial pressure test results ,the complete procedures curves which described the relationships between yielding strength、 peak strength、 residual strength and confining pressure was obtained. Taking the strain softening of rock into account, the bilinear elastic-linear softening-residual perfect plasticity four-linear model was put forward in this paper on the basis of the test results and theory of plasticity. This model was adopted to describe the behaviors of marble in different phases under Triaxial compression with the constitutive equation of strain softening phase as focus. The results indicated that the theoretic model fitted in well with the test results.

关键词： theory of plasticity conventional Triaxial compression test constitutive model control equation linear softening bilinear elastic

An anisotropic constitutive model of geomaterials based on true Triaxial testing and its application

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Journal of Central South University 2017年第6期24卷 1430-1442页

作者：张坤勇 Frederick Nai Charkley Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Nanjing 210098China Geotechnical Research Institute Hohai UniversityNanjing 210098China

Series of testing on coarse grained soils were carried out with a true Triaxial testing apparatus. The loads were applied from the major principal and minor principal directions, respectively, to simulate the construction and water impounding process of a rock fill dam. The stress and strain relationships induced by the different loading methods were investigated. A remarkable stress-induced anisotropy under complex stress state was observed. Contrary to popular assumptions in traditional numerical analysis and constitutive models, it was found that different elastic modulus and Poisson ratio exist in different principal directions in rock fill dams. From the testing results, an anisotropic constitutive model based on Duncan-Chang nonlinear model is presented to overcome the limitations of axi-symmetric assumptions in conventional Triaxial experiments and constitutive models. Both models were then applied in FEM analysis of an under-construction earth core high rock soil filled dam with the focus on hydraulic fracturing. The study reveals the major biases that exist when numerical analysis and constitutive models do not give serious consideration to the intermediate principal stress and anisotropy effects in soil rock built structures.

关键词： true Triaxial test stress induced anisotropy constitutive model complex stress state finite element method (FEM)