【作者】 梁军；

【导师】 苏超；

【作者基本信息】 河海大学 ， 水工结构工程， 2007， 硕士

【摘要】 岩土工程中的非连续变形问题随处可见，多种基于离散体系模型的非连续变形数值分析方法能够较好的分析这些问题，但每种方法都有其一定的局限性。DDA方法是解决非连续变形问题的一种比较有效的方法。本文重点研究了DDA方法的基本理论，发现其中存在两点主要不足：①块体的弹性变形采用等应变假设：②接触问题的处理采用虚拟弹簧，导致块体间可能相互嵌入。针对这两个问题开展研究并引入多体有限元方法，主要工作有：(1)详细介绍了多体有限元方法的基本原理。将有限单元法和多体系统动力学基本理论相结合，对每一弹性块体，用有限单元法计算块体的相对变形，块体与块体间通过接触力相互联系，系统的未知量为块体内部的位移和接触面的接触力以及块体的整体移动，通过接触面的位移协调条件和块体的整体平衡方程控制。最终形成一套完整的解决非连续变形分析的多体系统有限元方法；(2)在对接触问题作了一系列的假定基础上，给出了接触问题的接触判定条件。运用多体有限元理论，借助FORTRAN语言编制了多体有限元程序，叠梁算例表明计算方法可行，计算程序有效；(3)将多体有限元方法应用于层状岩体中的地下洞室围岩变形分析。相比于目前非连续变形分析使用的方法，多体有限元方法的能够很好的反应出接触面的接触状态和接触力，计算结果更符合工程实际的变化规律。更多还原

【Abstract】 In the geotechnical engineering, discontinuous modification question can be found everywhere, many kinds of discontinuous deformation numerical analysis methods based on the separate system model can well analyze these questions, but each method has its certain limitation.The DDA method is one of the effective methods for solving the problems of discontinuous modification.In this paper, the theory of DDA was studied in the key point and two disadvantages were found: First, each block was assumed to have constant strain; Second, virtual spring was used to settle contact problems, which led to the possible insertion among blocks. Based on these two problems studies were carried out and the multi-body FEM was put forward.The main contents can be shown as follows:(1) The basic principle of multi-body FEM was introduced in detail. Combined the theory of FEM with multi-body system dynamics ,the relative deformation of each block was calculated by FEM.the blocks were interrelated by contact force.and the deformation of each block,contact forces among blocks, whole motion of the block were considered as unknown quantities.which were governed by displacement compatibility on interface and global system balance equations. In this way, a complete set of multi-body FEM was formatted to make discontinuous deformation analysis.(2)Based on a series of assumptions, the criterion of contact problem was presented. Applied the basic principle of multi-body FEM, a program of the multi-body FEM was exploited with Fortran.The feasibility of the calculating method and the validity of the calculating program were indicated by the examples of stop logs.(3) The method of Multi-body FEM was applied in the deformation analysis of surrounding rock of underground cavern in the laminated rock. Compared with other methods adopted most presently in deformation analysis of underground cavern, the method of Multi-body FEM could better response the contact condition and contact force of the contact face,and the results made better agreement with the rule of the project real case.更多还原