论文部分内容阅读
以数值流形方法为基础 ,研究了岩体不连续非线性变形的数值模拟方法 ,并编制了相应的流形元程序 ,分析了岩土工程中某些具体问题的流形元模拟方法。(1)利用参变量变分原理建立了岩体弹塑性分析的数值方法。该方法能够求解非关联流动和应变软化的弹塑性问题 ,避免了在每个载荷步中迭代计算 ,提高了计算效率 ;(2 )根据覆盖接触理论 ,深入地研究了连续面上不嵌入和无张拉条件的数值实现方法 ,完成了相应的程序。在此基础上通过引入假想不连续面 ,提出了一种简化的岩体破坏分析方法 ,该方法直接根据假想不连续面上的应力状态用抗拉强度和抗剪强度进行破坏判断 ,不需要计算应力强度因子 ,也不需要增加单元或重新划分网格 ,数值实现比较方便。该简化方法还能求解采用断裂力学方法所不能模拟的岩体破坏问题 ;(3)研究了锚杆支护的流形元模拟方法 ,建立了锚杆支护的数值模型 ,该模型能够模拟普通锚杆、预应力锚杆和锚索 ;(4 )研究了地下水作用的流形元模拟方法 ,建立了地下水作用的简化计算模型 ;(5 )提出了一种用平面模型解一类特殊三维问题的方法 ,分别采用改进的二维模型和等效初始应力两种方式 ,考虑垂直于计算平面的正应力和正应变对计算平面变形的影响 ,此法比三维计算难度小 ,且节省计算时间
Based on the numerical manifold method, the numerical simulation method of discontinuous nonlinear deformation of rock mass is studied, and the corresponding manifold element program is compiled. The manifold element simulation method for some specific problems in geotechnical engineering is analyzed. (1) The numerical method of elastic-plastic analysis of rock mass is established by using the principle of variational variables. The method can solve the elasto-plastic problems of non-associated flow and strain softening, avoids the iterative calculation in each load step, and improves the computational efficiency. (2) According to the covering contact theory, Tension conditions of the numerical methods to complete the corresponding procedures. On the basis of this, by introducing imaginary discontinuities, a simplified method of rock mass failure analysis is proposed. The method is directly based on the stress state on the imaginary discontinuity, and is judged by the tensile strength and shear strength without any calculation Stress intensity factor, do not need to increase the unit or re-divide the grid, the numerical realization is more convenient. The simplified method can also solve the failure of rock mass which can not be simulated by the method of fracture mechanics. (3) The manifold element simulation method of bolt support is studied, and the numerical model of bolt support is established. The model can simulate the normal Anchor bolt, prestressed anchor rod and anchor cable. (4) The method of manifold element simulation for groundwater effect was studied and a simplified calculation model of groundwater effect was established. (5) A plane model was proposed to solve a special three-dimensional problem , Two methods of improved two-dimensional model and equivalent initial stress are respectively adopted to consider the effect of normal stress and normal strain perpendicular to the calculation plane on the calculation of plane deformation. This method is less difficult than the three-dimensional calculation and saves the calculation time