裂隙岩体中隧道变形破坏的节理有限元模拟计算

裂隙岩体是地下工程施工中经常遇到的一类岩体,研究其变形和破坏机理是工程安全施工的保证。以天平线关山隧道工程为例,采用基于修正Goodman单元的节理网络有限元法,将裂隙岩体看作由岩块和节理、裂隙组成的二元结构,其中岩块和节理、裂隙分别采用线性Mohr-Coulomb强度准则和非线性Barton-Bandis剪切强度准则。通过有限元软件Phase~2模拟分析了隧道开挖过程中裂隙岩体的变形破坏特点以及不同工况下隧道拱顶的沉降量,并讨论了Barton-Bandis准则中节理粗糙程度(J_(RC))的取值对围岩稳定性的影响。研究方法为裂隙岩体的数值计算提供了新手段,节理粗糙度(J_(RC))的反演结果能为支护设计和加固措施提供参考依据。

The Calculation of Tunnel Deformation and Failure in Fracture Rock Using Jointed#$NLFinite Element Simulation Method

The fractured rock massed are often met in underground engineering construction, Therefore, damage and deformation mechanism must be researched to ensure construction safety. In this paper, it is based on the projects of Guan Shan tunnel of Tian Ping railway, the joint finite element method(JFEM) based on modified Goodman element is proposed, regarding the fractured rock massed as rock block and fracture network, The Mohr-Coluomb criterion and Barton-Bandis criterion are applied to rock block and joint, respectively. Using the finite element software Phase2 to analyze the deformation and failure mechanisms of the fractured rock during the process of the tunnel excavation, and different influencing factors on the settlement of tunnel roof. The effect of the value of joint roughness coefficient(JRC) to the stability of the surrounding rock is also discussed. The new idea is proposed for the numerical modeling of the fractured rock, and the inversionSresults of JRC can also provide a reference for the support design and reinforcement measures.