三维应力作用下岩体层面效应分析

为得到层状岩体在真三轴压缩情况下的强度变形特征,利用数值分析方法建立计算模型,得到不同结构面倾角β下试样的应力和变形响应,结果表明,(1)加载初期,结构面倾角β=0°和β=90°试样对应的初始弹性模量最大;随着试样变形的增大,对应的弹性模量以β=90°、60°、0°的顺序逐渐减小;β=90°和β=0°试样发生破坏的脆性特征比较明显;(2)随着围压σ3=σ2的增大,压缩强度σ1不断增大;围压对强度极值发生的位置影响不大;(3)最小主应力与结构面走向平行情况下,随着中间主应力σ2的增大,试样压缩强度呈现先增大后减小的趋势;随着最小主应力σ3的增大,σ1逐渐增大;当σ3较小时,二者符合线性关系;随着σ3的增大,二者的关系逐渐呈现非线性特征;并且结构面滑移破坏型试样的非线性特征更加明显;(4)最小主应力与结构面走向垂直的情况下层状岩体的压缩强度与中间主应力和最小主应力的关系均呈现显著的线性特征。

The effect of structure plane in rock mass under tri-axial stress condition

In order to reflect the characteristics of strength and deformation of stratified rock mass under true triaxial compression, the calculation model is founded by numerical analysis method to obtain the stress and deformation responses of rock samples with different structure plane inclinations ?. The analysis results show that: (1) in the initial loading phase, the initial elastic modulus for samples with ? = 0° and ? = 90° are larger; with the increase of sample deformation, the elastic modulus of rock samples with ? = 90°, 60°, 0° decrease gradually; the brittle characteristics of samples with ? =90° and ? =0° of structure plane are obvious; (2) with the increase of surrounding stress ? 3 =? 2, the compressive strength ? 1 increases correspondingly; the surrounding stress does not have great effect on the location where the peak strength occurs; (3) for the situation of minor principal stress parallel to the structure plane strike, with the increase of intermediate principal stress ? 2, the compressive strength of rock samples shows the trend of first increase then decrease; with the increase of the minor principal stress ? 3, ? 1 increases gradually; when ? 3 is small, their relationship meets in the linear way; but with the increase of ? 3 their relationship transfers to the nonlinear way; and the rock sample with the failure model of slipping along structure plane shows the more obvious nonlinear characteristic; (4) for the situation of minor principal stress perpendicular to the structure plane strike, the compressive strength of stratified rock mass shows the obvious linear relationship with intermediate principal stress and minor principal stress.