基于三轴压缩数值试验的岩石损伤特性

Rock damage characteristic based on triaxial compression numerical experiment

为研究岩石的损伤特性,基于连续损伤力学理论和岩石微元强度服从Weibull分布函数,利用FLAC3D有限差分数值模拟软件,在围压分别为3,6,10 MPa的情况下,对岩石进行了不同变形参数(E和μ)和强度参数(c和φ)的常规三轴压缩数值试验研究。数值试验结果表明,(1)在加载初期,岩石出现负损伤(压密强化效应),随着轴向应力的增大,割线模量减小,泊松比增大;(2)黏聚力或内摩擦角或围压越大,岩石抗压强度越高,岩石变形过程中的塑性变形阶段越长;(3)损伤起点对应的轴向应变不随强度参数(c和φ)的变化而变化,但随计算初始弹性模量的增大而减小,随围压的增大而增大;(4)泊松比对岩石力学特性和损伤特性影响甚少,可忽略不计。

The study of rock whose the damage characteristic is carried out on the basis of the theory of continuum damage mechanics and rock infinitesimal strength obeys Weibull distribution function.The conventional triaxial numerical experiment under different deformation parameters(E,μ)and strength parameters(c,φ)and confining pressure which is respectively3/6/10MPa are carried out for the rock by using FLAC3D finite different numerical simulation software.The results of numerical experiment show that:①In the initial stage of loading,the rock shows negative damage(compaction reinforcement effect).With the increase of the axial stress,the cutting modulus decreases and Poisson′s ratio increases.②The higher the cohesion or internal friction angle or confining pressure is,the higher the compressive strength of rock is,and the longer the plastic deformation stage is during rock deformation.③The axial strain corresponding to the starting point of damage does not change with the change of the intensity parameters(c,φ),but decreases with the increase of the calculated initial elastic modulus and increases with the increase of confining pressure.④Poisson’s ratio has little influence on the mechanical properties and damage characteristics of rocks,and is negligible.