地下厂房试验洞的粘弹性反分析

Visco-elastic Back-analysis of Experimental Cavity in Underground Factory

结合某地下厂房试验洞量测资料的分析,研究成层各向异性岩体中洞室工程粘弹性问题的反分析方法。反分析计算时采用分层均质模型,将计算区域内各层岩层分别视为均质各向同性体,初始地应力假设成线性分布。有限元分析中,对倾斜成层的岩层、软弱夹层及断层节理等分别划分了单元,以模拟成层岩体的分布特征及其对洞室工程在受力与变形方面所产生的一些各向异性宏观效应。为使计算过程简化,对离洞室较远的地层按地质资料对材料特性参数赋值,通过弹性反分析计算出地层初始地应力;采用三元件模型,建立围岩粘弹性反分析模型,反演求得试验洞相邻围岩的粘弹性参数值。为工程设计与支护提供了可靠的依据。

Based on the measured data of a certain experimental cavity in underground factory, the paper studied a visco-elastic back analysis method of experimental cavity. It assumed that the initial rock stresses is in linear distribution, all layers of strata are regarded as layered homogeneous in calculation districts, and this model is applied to doing calculation. As to the slant and layered stratum, flaccidity interlayer and fault texture, they separately plotted into elements to simulate the distributive character of layered rock mass and some anisotropic macro-effects of cavity engineering on the stresses and strains in finite element (FEM) analysis. According to the geological data,we evaluated rock medium characteristic parameters on these strata away from the cavity to simplify the calculation. The paper calculated the value of initial rock stresses by elastic back analysis, and achieved the material visco-elastic parameters of the surroundings in neighboring experimental cavity by applying tri-element model to back analysis. It provided reliable basis for the engineering designs and supports.