岩石非线性拉、压蠕变模型及其参数识别

基于岩石单轴拉、压作用下加速蠕变曲线的幂函数拟合分析，推导了二元件黏塑性蠕变模型中黏性元件的非线性表达式，并将建立的非线性黏塑性模型与Burgers蠕变模型串联建立一个新的非线性黏弹塑性拉、压蠕变模型。分析显示该模型能够描述岩石在直接拉伸、压缩作用下的衰减蠕变、稳态蠕变和加速蠕变3个阶段。结合对重庆红砂岩单轴直接拉伸与单轴压缩蠕变试验结果，通过Matlab编写Quasi-Newton优化算法(BFGS)实现了岩石非线性黏弹塑性拉、压蠕变模型的参数辨识，辨识参数相关性系数平方R 2均在96%以上。将模型与修正西原模型比较发现非线性黏弹塑性拉、压蠕变模型线型吻合程度均高于修正西原模型，表现出拉、压蠕变特性的适用性，从而进一步验证了模型描述岩石拉伸以及压缩蠕变特性的正确性。

Nonlinear creep model of rock in tensile or compressive stress and its parameter identification

Based on the power function fitting analysis of acceleration creep curves of rocks in tensile and compressive stress,a nonlinear expression of viscous components in the visco-plastic creep model was derived,which then incorporated with the Burgers creep model to achieve the building of a new nonlinear creep model.This new model can well describe the decay,steady-state and acceleration creep stages of rocks in tensile or compressive stress.Combined with creep test results of red sandstones in Chongqing under...