Rock and Soil Mechanics ›› 2020, Vol. 41 ›› Issue (7): 2179-2188.doi: 10.16285/j.rsm.2019.6673

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Study on constitutive model of fractured rock mass based on statistical strength theory

GAO Wei1, 2, HU Cheng-jie1, 2, HE Tian-yang1, 2, CHEN Xin1, 2, ZHOU Cong1, 2, CUI Shuang1, 2   

  1. 1. College of Civil and Transportation Engineering, Hohai University, Nanjing, Jiangsu 210098, China 2. Key Laboratory of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China
  • Online:2020-07-10 Published:2020-12-22
  • About author:GAO Wei, male, born in 1971, PhD, Professor, research interests: rock mechanics theories, stability analysis and big data application in engineering.
  • Supported by:
    the National Natural Science Foundation of China (41831278) and the Fundamental Research Funds for the Central Universities (2016B10214).

Abstract: With the aid of damage mechanics and on the basis of statistical strength theory, a method for establishing the constitutive model of deep fractured rock mass is proposed and verified by laboratory and numerical tests. The fractured rock mass is divided into numerous micro-cubes. The strength of micro-cubes is related to the fracture degree and the strength of each micro-cube is randomly distributed. Thus the strength can be used to reflect the fracture degree of the rock mass. Among them, based on the fact that the work done by friction between fracture surfaces is equal to the strain energy released after the material fracture, the rock fracture degree variable defined from the mechanical point of view is obtained. In addition, it is assumed that the strength distribution of micro-cubes obeys the Weibull distribution and the stress behavior satisfies Hoek-Brown criterion. The constitutive model of fractured argillaceous sandstone rock mass is then established and verified based on typical triaxial test results of fractured rock samples. The results show that the calculated curve from theoretical model is in good agreement with the test results. At last, a supplementary numerical test is carried out using discrete element software PFC, which further proves the good calculation performance of theoretical model for argillaceous sandstone and the feasibility of the constitutive model establishing method proposed in this paper.

Key words: fractured rock mass, constitutive model, statistical strength theory, Hoek-Brown criterion, Weibull distribution, argillaceous sandstone