基于三轴压缩试验的红砂岩本构模型

Constitutive model of red sandstone based on triaxial compression test

利用RMT150B型岩石力学多功能试验机对红砂岩试样在不同围压条件下的三轴压缩应力应变全过程曲线进行了系统试验研究。研究表明:围压增大,岩石的峰值强度也随着增高;红砂岩的体积应变在峰值后区表现出很大的剪胀性。基于试验结果,分析了岩石屈服强度、峰值强度、残余强度与围压之间的关系,根据试验得到了典型三轴压缩应力应变全过程曲线,建立了一个由线弹性段Ⅰ、线弹性段Ⅱ、线性软化段、线性残余塑性流动段组成的线性本构模型,给出了红砂岩4个阶段的本构方程,并确定了相关参数。

By using multi-function testing machine RMT150B for rock mechanics, the stress-strain complete process curve of red sandstone with triaxial compression under different confined pressures is systematically studied. With the increase of confined pressure, the peak intensity of the rock increases. The volumetric strain of red sandstone displays obvious dilatancy in the post-peak zone. Based on the results of the test, the relations among the rock＇s bend intensity,peak intensity, remanent intensity and the confined pressure are analyzed. And based on the stress-strain complete process curve of red sandstone from the test, a linear constitutive model, which is composed of linear elastic segment Ⅰ , linear elastic segment Ⅱ , linear softening segment,linear remanent plastic flow segment, is constructed , the constitutive equations of red sandstone in the four phases are given, and the related parameters are confirmed. 6 figs, 7 refs.