基于Hoek-Brown准则的岩石拉-拉剪破坏有限元模拟方法研究

Research on the Finite Element Simulation Method for Rock Tension and Tension-shear Failure Based on Hoek-Brown Criterion

岩石的拉伸、拉伸剪切破坏是工程中常见的破坏类型,基于Hoek-Brown准则研究提出一种模拟岩石拉伸、拉剪破坏的有限元计算方法。首先,结合岩石室内试验数据分析,Hoek-Brown准则可以很好地描述岩石拉伸、拉剪的力学性质。同时,鉴于岩石拉伸、拉剪破坏大都表现出脆性破坏的特征,可采用脆塑性本构模型近似模拟这种变形破坏。接着,推导给出Hoek-Brown准则的脆塑性本构模型有限元实现过程,将其嵌入有限元计算软件ABAQUS中。然后,对室内试验进行有限元模拟,模拟曲线与试验数据拟合良好,证明Hoek-Brown准则的脆塑性本构模型可以正确反映岩石拉伸、拉剪等破坏特征。最后,将所建模型应用于某输水隧洞工程,针对特征断面分析仅采用管片衬砌的可行性,为工程的衬砌设计提供指导。

Tensile and tensile-shear failure of rock is a common failure in engineering. Based on Hoek-Brown criterion, this paper presents a finite element method to simulate the tensile and tensile-shear failure of rock. Firstly, according to the test data of rock, Hoek-Brown criterion can well describe the mechanical properties of rock under tension and tension-shear. At the same time, brittle failure is the main feature of rock under tension and tension-shear. So brittle-plastic constitutive model is used to simulate the deformation and failure. Then, the solution method of stress drop is deduced, which is embedded in the finite element software ABAQUS. Next, the finite element simulation of the indoor test is carried out. The simulation curve fits well with the test data, the brittle-plastic constitutive model of Hoek-Brown can correctly reflect the failure characteristics of rock such as tension, tension-shear. Finally, the model is applied to a water conveyance tunnel project to analyze the feasibility of using segment lining on characteristic section, which provides a reference for the lining design of the project.