岩体裂隙模拟的扩展有限元法应用研究

Application of extended finite element method in modelling fracture of rock mass

岩体中普遍存在着断层﹑节理和裂隙等结构面,这些结构面的存在和发展对岩体的整体强度﹑变形及稳定性有极大的影响。因此,研究岩体中原生结构面的萌生﹑发展以及贯通演化过程对评估岩体工程安全性和可靠性具有非常重要的理论与现实意义。扩展有限元法(XFEM)作为一种求解不连续问题的有效数值方法,模拟裂隙时独立于网格,因此,在模拟岩体裂隙扩展﹑水力劈裂等方面具有独特优势。针对扩展有限元法的基本理论及其在岩体裂隙扩展模拟中的应用展开了研究,建立了扩展有限元法求解岩体裂隙摩擦接触、岩体裂隙破坏等问题的数值模型,并将计算模型应用于岩质边坡稳定性分析和重力坝坝基断裂破坏等工程问题。

Faults, joints and fractures are widely distributed in rock masses, and these discontinuities of existence and development have a significant effect on the whole strength, deformation and stability of rock mass. Thus, studying the evolvement of initiation, propagation and coalescence of primary flaws is of significance in theory and practice for estimating the safety and reliability of rock engineering. The extended finite element method （XFEM） is a numerical method for modelling discontinuities within the classical finite element framework. Since the computation mesh in XFEM is independent of the discontinuities, re-meshing for moving discontinuities can be overcome. Owing to the unique advantage for fracture analysis, XFEM has been employed to simulate hydraulic fracture and crack propagation of rock mass. The basic theory of XFEM and its application in simulating crack propagation are studied in detail. The numerical model of solving the frictional contact problem and hydraulic fracture propagation is developed. The calculation model is used to solve some geotechnical problems, such as deformation and failure of jointed rock slopes and modelling fracture propagation of gravity dam foundations.