改进的Poyting-Thomson岩石蠕变模型研究

Study of Improved Poyting-Thomson Creep Model for Rock

一般情况下,岩石蠕变分为3个阶段,即衰减阶段,稳态阶段及加速蠕变阶段,目前用于描述岩石蠕变的传统元件虽然可以较好地模拟蠕变的前两个阶段,但是对岩石蠕变第3个阶段的模拟效果并不是很好.因此,本文在Poyting-Thomson模型的基础上,引入一种非线性流变元件并对其进行改进,将改进后的元件与Poyting-Thomson模型进行串联,形成四元件流变模型,该模型不仅能够较好地模拟出岩石蠕变全过程,而且具有结构形式简单,参数较少等优点.然后,本文推导出四元件模型的本构及蠕变方程,并研究加速蠕变阶段的参数辨识方法.其次,利用前人所研究的岩石蠕变试验曲线对本文提出的蠕变模型进行参数确定及模型验证,最后将得出的理论蠕变曲线与试验曲线进行比较,结果表明,本文所构建的四元件非线性蠕变模型具有一定的正确性与可行性.

In general, the process of rock creep can be divided into three stages, namely the attenuation stage, the steady-state stage and the accelerative creep stage recently, the components used to describe rock creep are linear components. Although, these traditional components can simulate the first two stages of rock creep, but it can not well simulate the accelerative creep stage. Based on the Poyting-Thomson model, this paper introduces an improved nonlinear rheological component and connects the improved component with the Poyting-Thomson model~ the four- component rheological model not only can simulate the whole process of rock creep, but also has the advantages of simple structure and less parameters. The constitutive and creep e- quations of the four-component model are deduced~ and the method of parameter identification creep is inves- tigated. Finally, the model parameters are determined by using the rock creep curve. The paper compares the theoretical creep curve with the experimental curve so as to verify the correctness and feasibility of the four- component nonlinear creep model.