| Fractured rock mass is one of the most common and important engineering materials in many industries such as energy, transportation, hydroelectric engineering, and mining. This study is focused on the meso-mechanical characteristics of fractured rock mass with nonpenetrative fissures during failure, and estimation the deformation and strength mechanical parameters by the scientific methods. To simulate the failure of fractured rock mass with nonpenetrative fissures, a meso-mechanical analysis model has been set up in this paper. A series of numerical model tests have been carried out to study the characteristics of deformation, distribution of stress, characteristics of failure, and process of failure, that related to the fractured rock mass. From the conclusions draw from the results after the numerical model tests, some laws that reflect the change of increasing and decreasing of strength for the fractured rock mass and some typical failure models of fractured rock mass have been presented. A new method of estimating the deformation and strength parameters, such as deformation modulus, poisson's ratio, shear modulus, inner cohesion, inner friction angle, have been derived by theoretic method and taking the fissure's factors and conditions of applied stress. Main summarizations listed as blow:(1) To simulate the failure of the fractured rock mass with nonpenetrative fissures, an inhomogeneous damage plasticity model is assembled in ABAQUS, by adding the Weibull distribution for mechanical parameters of rock. The numerical model is validated by the results from some typical physical model tests carried out on MTS system. The numerical model can represent the features possessed by fractured rock mass, such as discontinuous, inhomogeneous, anisotropic, and not elastic. In the numerical model, an analytical rigid body model is applied to simulate the loading board in physical model test, which shows a well simulation of boundary condition in numerical tests.(2)A series of numerical model tests are performed by the inhomogeneous damage plasticity model on ABAQUS, these tests include model rock mass sample with one crack, two cracks, or 9 cracks. The key factors influenced the strength and deformation of rock mass, such as dip of fissure, confining pressure, friction angle of fissure, layout of fissure, are studied in these numerical model tests. Some mechanical phenomena on model samples are discussed, for example 1 st principle stress, shear stress, initiation of induced crack, trace of failure and peak compressive strength. According to these results, some laws that reflect the change of increasing and decreasing of strength for fractured rock mass with the change of dip of fissure, confining pressure, friction angle of fissure, layout of fissure, and some typical failure models of fractured rock mass are presented(3)Based on the theory of equilibrium of deformation, a formula is derived by theoretic method, taking the layout of fissure and directions of applied force. The formula can be utilized to calculate the deformation modulus, poisson's ratio, and shear modulus, taking the deformation modulus, poisson's ratio of intact rock, filling, tangential stiffness, and normal stiffness. The validity of the formula is verified by the reasonable analysis. According to the formula, some change laws of deformation modulus, poisson's ratio, shear modulus, with the change of dip of fissure and layout of crack, are presented.(4)Based on the hypothesis of simultaneous failure on the failure zone and two failure models, Formulas are derived by theoretic method, taking the layout of fissures, fissure persistence, to calculate the inner cohesion, inner friction angle, and compressive strength. The validity of the formula is verified by the theoretic analysis. According to these formulas, some laws that reflect the change of inner cohesion, inner friction angle, and compressive strength, with the change of dip of fissure and layout of fissure, are presented.
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