单一岩石变形特性及本构关系的研究

Research on distortion of singlerock and constitutive relation

利用MTS815岩石材料试验机试验,得到了在不同围压下砂岩的应力-应变全过程曲线及曲线上的压密、弹性、应变硬化(塑性)和应变软化(破裂)的4个阶段。分析了各阶段岩石的变形特性和围压对岩石强度的影响。根据岩石的变形特性提出以Duncan模型为基础的、能够描述岩石压密、弹塑性和破裂段的单一岩石本构模型,用改进的模型分析了岩石变形破坏机理。实验表明,提出的改进本构关系能更好地描述岩石的变形和破裂。

The experiment conducted on MTS815 Rock Testing Machine recorded the whole-process curve of sandrock stress-strain under different confining pressures and investigated the four different phases on the curve as compacting, elastic behavior, strain hardening (plasticity) and strain softening (abruption). It analyzed at the same time the distortion character at each individual phase and the effect on rock hardness subjected to confining pressure. Then, according to this distortion character of rock, a single rock constitutive model based on Duncan Model is developed which is capable to describe rock compacting, elastic behavior and abruption. The improved model is used to illustrate the mechanism of rock distortion and abruption. It has been tested in experiment that the improved constitutive relation can do better in describing rock distortion and abruption.