基于蠕变模型隧道开挖的数值模拟研究

Numerical Simulation Study of Tunnel Excavation Based on Creep Model

依据西藏某隧道工程,参考该隧道的地形、岩性条件,使用有限元差分软件FLAC 3D建立数值模型。采用BURGERS黏弹塑性模型(Model Mechanical CVISC),通过正交实验,研究了Maxwell动力黏度、Kelvin动力黏度、Kelvin弹性剪切模量和Maxwell弹性剪切模量对应力和位移值大小的影响;分析了蠕变作用下围岩总位移和残余应力在不同初始应力条件下随时间的变化情况。结果表明:Maxwell动力黏度和Kelvin弹性剪切模量对位移值具有很大的影响;Maxwell弹性剪切模量、Kelvin动力黏度对位移值的影响微乎其微;对应力大小产生影响的主要因素是Maxwell动力黏度。所取得的研究成果为现场的实际施工提供了有力的理论支撑。

According to a tunnel project in Tibet,referring to the terrain and lithology conditions of the tunnel,the finite element difference software FLAC3D is used to establish the numerical model.The influence of Maxwell dynamic viscosity,Kelvin dynamic viscosity,Kelvin elastic shear modulus and Maxwell elastic shear modulus on stress and displacement value was studied by orthogonal experiment by using the URGERS Visco-Elastic-Plasticity Mechanical Model,and the change of total displacement and residual stress of surrounding rock with time under different initial stress conditions was analyzed.The results show that the Maxwell dynamic viscosity and the Kelvin elastic shear modulus have a great influence on the displacement value,the Maxwell elastic shear modulus and the Kelvin dynamic viscosity have little influence on the displacement value,and the main factor affecting the stress is the Maxwell dynamic viscosity.The research results provide a strong theoretical support for the actual construction on site.