隧道围岩卸荷演化过程的Kolmogorov熵分析

Kolmogorov entropy analysis of surrounding rock system in the processing of unloading for deep-buried tunnels

岩石材料本质上是一种物理非线性的材料,在深埋条件下,隧道围岩系统的变形还表现出几何非线性,这两种非线性机制的相互作用使得围岩系统的卸荷演化具有高度的复杂性。根据重庆某深埋隧道围岩实际情况,建立了摩尔-库仑剪破坏与拉破坏复合的应变软化模型,运用三维显式有限差分程序FLAC3D软件,采用大变形方法对深埋隧道围岩系统卸荷进行数值仿真,同时基于耗散结构理论,对深埋隧道围岩系统卸荷演化的双重非线性数值计算结果行整合,提取了围岩系统演化过程中特征点演化时间序列的Kolmogorov熵值,判断了系统演化的混沌特性及其对初始条件的敏感性,分析了系统卸荷过程的能量耗散特征,研究了围岩的失稳机制。

Rock is a kind of physical nonlinear complicated medium, under deep-buried condition the surrounding rock system deformation shows geometrical nonlinear characteristic, and the interaction between the two nonlinear mechanism makes the unloading of surrounding rock system evolving complexly. Based on the Lagrangian method and large deformation caculation method, both the double-nonlinearity and nonlinear dynamics character of deep-buried tunnel surrounding rock system under unloading are studied. The numerical model results show that the Kolmogorov entropy has been extracted from the evolution data in the unloading process of surrounding rock system. The analysis indicates that the typical chaos character has been demonstrated in the process of unloading for deep-buried tunnel surrounding system and the rock mass energy dissipation is analyzed at the stage of unloading.