三维离散元改进算法及其在三峡永久船闸高边坡工程中的应用
文献类型：学位论文
| 作者 | 高波
|
| 学位类别 | 硕士 |
| 答辩日期 | 1999 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 李世海 |
| 关键词 | 三维离散元 面-面接触模型 平行六面体单元 滑动块体 船闸 水利工程 3-dimensional distinct element plane to plane contact model parallelepiped element sliding-blocks |
| 学位专业 | 工程力学 |
| 中文摘要 | 本文根据面－面接触模型，写出了三维离散元的物理方程及运动方程，对于接触刚度、阻尼系数、时步、计算控制及块体的滑动失稳判据等作了讨论。在NURBM－3D 长方体单元基础上改进了其划分单元的算法，依据岩体中三组真实的节理面划分平行六面体单元，实现了网格的自动剖分，从而可以将单元视为真实的岩块，更客观地体现了节理面对岩体稳定性的影响。运用改进后的三维离散元方法，编制了计算程序，对三峡工程永久船闸高连坡开挖进行了模拟。计算过程包括初始地应力场模拟、岩体开挖过程两个阶段。模拟计算首先给出了为水平、垂直节理面所切割的长方体单元情况下的应力场分析，考证了程序的可行性。将已有的三峡永久船闸实测节理简化为三组节理，完成了初始地应力场的模拟，给出了分四步开挖后的岩体位移场和应力场，计算出岩体开挖过程中产生滑动块体的位置，其结果可以定性地表明：沿节理面的块体滑动是边坡失稳的主要模式。编制的后处理程序提供了计算数据库与绘图软件Origin的接口，可以画出任意剖面或节理面上的应力等值线、位移矢量图及滑动块体分布图，由此可以直观判断岩体不稳定区域和高应力区范围。编制的计算程序在PC机上计算了10万块体单元，用于模拟大型工程，其计算结果与有限元及类似的连续介质模型相比更为合理，为用离散元法进一步研究可变形块体及岩体的蠕变提供了一种切实可行的工具。将离散元法应用于大型工程三维计算是可行的，但在本构模型建立、岩体破坏参数选择等方面均有等于更深入的研究，其结果也有待于更多工程的验证。 |
| 索取号 | 29859 |
| 英文摘要 | According to plane to plane contact model, the constitutive and dynamic equations for 3-dimensional distinct element have been derived in this thesis. The contact stiffness, damping coefficient, time step, computation control and slide instability for blocks have also been discussed. Based on the regular cuboid elements of NURBM-3D, the algorithm to generate elements is modified. The parallelepiped elements have been created by the intersection of three sets of physical joints in rock mass and an automatic mesh generation program has been completed. Thus the elements can be regarded as natural blocks, which reflects the effect of the joints on the stability of the rock mass objectively. A new procedure have been developed by using the modified algorithm, and numerical analysis has been made of the process while the rock mass are being excavated of high steep slopes of permanent navigation lock at the Three-Gorges Project. The computation consists of the simulation of the initial stress and the process of excavation. First the stress field has been simulated for cuboid elements intersected by horizontal and vertical joints, which verified the validation for the code. By simplified the natural joints in the Three-Gorges permanent lock area to three sets of joints, the simulation of initial stress field and four-step excavation have been completed, Both the corresponding displacement and stress field and the locations of the sliding blocks have also been obtained. It is showed that block-sliding along joints is the main reason resulting in slope instability. The post-disposing code provides an interface between the computational data and the plot software-Origin. Stress graphs, displacement vector graphs on every section plane or joint plane and the sliding blocks distribution can be plotted. The unstable area and high stress area in rock mass are given out for analysis. Using PC the new 3-D code performed computation for 100,000 blocks to simulate the large-scale project. Comparing with finite element method and other continuous medium model, the results of discrete element method is more reasonable. The result provides a practical tool for later research in deformable blocks and rock mass creep. It is feasible to use the distinct element method in large-scale project. Of course, further research is needed in establishing constitutive model and choosing rock failure factors. The results of this thesis also require to be verified by more projects. |
| 学科主题 | 工程力学 |
| 语种 | 中文 |
| 公开日期 | 2009-04-13 ; 2009-08-25 |
| 出处 | [硕士论文].北京.中国科学院力学研究所,1999 |
| 源URL | [http://dspace.imech.ac.cn/handle/311007/23034]  |
| 专题 | 力学研究所_力学所知识产出(1956-2008) |
| 推荐引用方式 GB/T 7714 | 高波. 三维离散元改进算法及其在三峡永久船闸高边坡工程中的应用[D]. 北京. 中国科学院研究生院. 1999. |
入库方式： OAI收割
来源：力学研究所
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