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A novel elastoplastic model for Yunnan sandstone under poly-axial loading

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International Journal of Mining Science and Technology 2023年第7期33卷 801-814页

作者： Xu Li Guangyao Si Joung Oh Ismet Canbulat Rui Kong Jian Zhang School of Minerals and Energy Resources Engineering University of New South WalesSydney NSW 2052Australia Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang 110819China School of Safety Science and Engineering Henan Polytechnic UniversityJiaozuo 454003China

The lack of understanding of plastic hardening(softening)laws,especially under anisotropic stress conditions,results in inappropriate geotechnical *** of the yielding envelopes do not consider the effect of intermediate principal stress and the influence of Lode's *** addition,the application of plastic flow rules regarding yielding surfaces compromises the softening of rock internal friction as well as the influence of Lode's angle on the plastic ***,the ductility to brittleness transition in the intermediate principal stress direction still requires a theoretical *** this study,based on poly-axial testing results of Yunnan sandstone,we adopted a failure criterion with the intermediate principal stress proposed by Menétrey and *** proposed new failure envelope was applied to capture the plastic evolution of rock samples.A plastic hardening-softening model is constructed,based on the framework of the plastic *** softening envelope is modified to better present the stress drop and considers the deterioration of rock internal friction in the post-peak stage of poly-axial *** differential of plastic potential according to the principal stresses is also modified,considering the rotation of Lode's angle in the poly-axial loading *** model results were compared with laboratory testing results,which showed great consistency across 9 different loading tests(5 under triaxial stress and 4 under poly-axial stress with 22 stress-strain curves in total).The induced brittleness by the intermediate principal stress is also well captured by the proposed model.

关键词： elastoplastic model Rock mechanics Poly-axial stress state True-triaxial

A new elastoplastic model for bolt-grouted fractured rock

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International Journal of Mining Science and Technology 2024年第7期34卷 995-1016页

作者： Haoyi Li Shuangying Zuo Peiyuan Lin State Key Laboratory for Tunnel Engineering Sun Yat-Sen UniversityGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory Zhuhai 519082China School of Civil Engineering Sun Yat-Sen UniversityGuangzhou 510275China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China

Complexities in mechanical behaviours of rock masses mainly stem from inherent discontinuities,which calls for advanced bolt-grouting techniques for stability *** the mechanical properties of bolt-grouted fractured rock mass(BGFR)and developing accurate prediction methods are crucial to optimize the BGFR support *** paper establishes a new elastoplastic(E-P)model based on the orthotropic and the Mohr-Coulomb(M-C)plastic-yielding *** elastic parameters of the model were derived through a meso-mechanical analysis of composite materials mechanics(CMM).Laboratory BGFR specimens were prepared and uniaxial compression test and variable-angle shear test considering different bolt arrangements were carried out to obtain the mechanical parameters of the *** showed that the anisotropy of BGFR mainly depends on the relative volume content of each component material in a certain ***,the mechanical parameters deduced from the theory of composite materials which consider the short fibre effect are shown to be in good agreement with those determined by laboratory experiments,and the variation rules maintained good ***,a case study of a real tunnel project is provided to highlight the effectiveness,validity and robustness of the developed E-P model in prediction of stresses and deformations.

关键词： Bolt-grouted fractured rock mass elastoplastic model Composite materials mechanics Laboratory experiment

Triaxial elastoplastic damage constitutive model of unreinforced clay brick masonry wall

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Earthquake Engineering and Engineering Vibration 2023年第1期22卷 157-172页

作者： Wu Biye Dai Junwu Bai Wen Yang Yongqiang Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina EarthquakeAdministrationHarbin 150080China Key Laboratory of Earthquake Disaster Mitigation Ministry of Emergency ManagementHarbin 150080China

Due to differences in the properties of composition materials and construction techniques,unreinforced masonry is characterized by low strength,anisotropy,nonuniformity,and low *** order to accurately simulate the mechanical behavior of unreinforced brick masonry walls under static and dynamic loads,a new elastoplastic damage constitutive model was proposed and the corresponding subroutine was developed based on the concrete material constitutive *** the proposed constitutive model,the Rankine strength theory and the Drucker-Prager strength theory were used to define the tensile and compressive yield surface function of materials,***,the stress updating algorithm was modified to consider the tensile plastic permanent deformation of masonry *** verify the accuracy of the proposed constitutive model,numerical simulations of the brick masonry under monotonic and cyclic uniaxial tension and compression loads were carried *** among the numerical and theoretical and experimental results show that the proposed model can properly reflect the masonry material mechanical ***,the numerical models of four pieces of masonry walls with different mortar strengths were *** cyclic loadings were applied and the results show that the proposed constitutive model can properly simulate the wall shear failure characteristics,and the force-displacement hysteretic curves obtained by numerical simulation are in good agreement with the ***,the proposed elastic-plastic damage constitutive model can simulate the nonlinear behavior of unreinforced brick masonry walls very well,and can be used to predict the structural response of masonry walls.

关键词： brick masonry elastoplastic model calibration parameters numerical simulation damage variable