Title of Paper:岩体尺寸效应及其特征参数计算

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Date of Publication:2022-06-30

Journal:岩石力学与工程学报

Affiliation of Author(s):建设工程学部

Issue:6

Page Number:1157-1166

ISSN No.:1000-6915

Abstract:The rock size effect, including intact rock size effect and size effect of jointed rock mass, is a hot topic in rock mechanics and rock engineering. However, determining the parameters of intact rocks and the rock mass with randomly distributed joints is much difficult in numerical simulations. In this paper, it is assumed that the rock mass is composed of intact rock with joints. Based on physico-mechanical test and microscopic parameter statistical theory, a statistical model is built to study the intact rock scale effect. Based on the statistical analysis of macro joint distribution, a macroscopic rock mass model is put forward to investigate the rock mass scale effect. The main idea is described as follows: (1) A statistical model can be established by analyzing the data of the laboratory experimental tests of intact rocks. The representative element size and its strength can be obtained by studying the scale effect of the intact rocks. (2) By determining the mechanical parameters of the joints and the geometric distribution parameter of the joints, the numerical network model of joints can be established. (3) The rock mass model with different scales can be built to study the rock mass scale effect, and then, the representative element size and its strength can be calculated. By using the strength reduction FEM or centrifugal loading method, the stability of the rock engineering can be analyzed according to the mechanical parameters of the jointed rock mass. Finally, the influences of the heterogeneity, confining pressure and density of joints on rock size effect are discussed. With increase of heterogeneity, representative element volume of rock sample increases; with increase of confining pressure, the representative strength increases but the increase of representative element volume is not obvious; with increase of density of joints, the representative element volume and strength decrease. The results will be useful for understanding the rock mass scale effect and provide a helpful way to obtain the mechanical parameters of jointed rock mass.

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