位移反分析在隧道工程有限元数值模拟中的应用

Application of displacement back analysis in finite element numerical calculation of tunnel project

如何更加准确地获取岩土体的力学参数是提高有限元计算结果准确性的前提。以江西寻乌—全南高速公路桂云山隧道为例,提出采用位移反分析的方法获取围岩的力学参数。根据现场监控量测数据,基于位移反分析程序得到围岩的等效弹性模量及侧压力系数,并将由反分析得到的等效弹性模量及侧压力系数和规范建议的取值分别代入到MIDAS/GTS有限元模拟计算,相比之下,发现基于位移反分析的计算结果与实测值更为接近,表明通过反分析的方法获取岩土体力学参数的途径是可行的。

How to acquire the mechanical parameters of rock and soil more precisely is a typical premise to improve the precision of finite element calculation. On the basis of Guiyunshan tunnel under construction of Xunwu-Quannan expressway,the method of displacement back analysis was proposed to acquire the mechanical parameters of surrounding rock. Based on the displacement back analysis procedure,the equivalent elastic modulus and lateral pressure coefficient were acquired according to the spot measured value. In the process of MIDAS/GTS finite element calculation,the equivalent elastic modulus and lateral pressure coefficient and the parameters suggested from related standard were adopted respectively. Facts and figures show that the calculated results based on the back analysis are more consistent with the field measurement raw data,and it is feasible to acquire the mechanical parameters of rock and soil by means of the way of back analysis.