【作者】 王宗魁；

【导师】 任大春；

【作者基本信息】 长江科学院 ， 岩土工程， 2008， 硕士

【摘要】 地下洞室工程一般都是建在地下几十米甚至上百米深,且规模越来越大,空间布置越来越复杂,因此对围岩结构稳定性分析尤其重要,而影响结构稳定性的很重要原因是变形。本文基于非线性有限元理论基础,利用MSC.MARC有限元分析软件模拟三峡右岸地下电站洞室群的开挖,分析洞室应力变形规律。本文对洞室围岩稳定性及洞室群开挖相互影响的研究现状进行了系统地综述,详细描述了研究区工程概况与地质条件,介绍了弹塑性屈服理论、非线性有限元分析方法以及MSC.MARC工程应用软件。运用MARC有限元软件建立地下洞室平面应变模型,首先建立三个平行布置的平面应变洞室模型,通过调整间距,分析洞室群间距对洞室围岩应力变形的影响;其次,对地下电站主厂房进行一次开挖和分层开挖模拟,一方面对比分析不同开挖方案的优缺点,另一方面研究分层开挖时拱顶和边墙变形规律。收集三峡地下电站主厂房开挖实施过程中的岩体变形监测成果,与上述数值计算结果进行对比分析,说明上述研究成果的正确性。主要结论如下:1、地下洞室群的变形与各洞室之间的间距有关,当间距小于2倍洞径,变形开始迅速增大,说明本文条件下地下洞室群的影响范围为2倍洞径。2、一次成洞开挖与分层多次开挖相比,产生的应力大小和塑性屈服区均有所增加,但开挖产生的位移量有所减小,但总的来说这些差异不是很大。3、随着主厂房自上而下的逐渐开挖,地下洞室两侧边墙向洞室内变形,顶拱的垂直变形呈现先向开挖面沉降,后回弹并向上隆起的现象。4、地下电站主厂房边墙水平位移最大值在开挖初期发生在洞室顶角,相对高度为1.0,当开挖高程达到相应洞宽时,相对高度降至0.5,随着开挖的继续进行,相对高度逐渐减小,最终基本稳定于0.38。更多还原

【Abstract】 The underground hole room project is generally constructed several dozens meters even over a hundred meter depth underground, and the scale is getting larger and larger, the spatial arrangement is getting more and more complex, therefore it is important to analysis the adjacent formation structural stress distortion. This article is based on nonlinear finite element rationale, simulated Three Gorges right bank underground power plant hole room group excavation by MSC.MARC finite element analysis software and analysised hole room strain rule.This article summarized the stability of the wall rock and the mutual influence to the hole room groups systematically. Described the engineering general situation and the geologic condition of the research zone, introduced the elastoplasticity submitted the theory, the finite element analysis method as well as the MSC.MARC software, elaborated the research area project survey and the geological condition in detail.To establishment the underground hole room plane strain mechanical model using the MARC finite element software, firstly,establishes finite element model which three hole room parallel arrangement excavates, adjustment hole room size, analysis hole room group size to hole room adjacent formation strain influence.Secondly,carries on one time excavates and the lamination excavates the simulation, carries on the analysis comparison to two kind of plan computed result, discovers the respective good and bad points.Collceting the rock deforming monitoring outcome in the process of excavation about Three Gorges main plant,and contrasted analyzing with the calculated outcome in the previous description,we can illustrate the axaction of the research findings.Main conclusions:1. The distortion of the mass of underground room is affected by the distance of each other. The distortion increases rapidly when the distance is less than 2 times of the room’s width. This indicated that the affecting scope of excavation is twice width of the room under the cause of this paper.2. If excavation is done in a short time, the stress and yield zone is larger than that when the excavation is preceded in many steps. But the displacement is smaller in later case. However, the difference is very little.3.As exacavating from the top of hole to the bottom, the side walls of underground hole deform to the inner of the hole. the direction of vertical distortion of the crown is upside at first and then the direction is downside.4.The maximal horizontal displacement of edge wall is appeared in top corner of grotto during the first period of excavating, and the relative height is 1.0. When the excavation altitude is as high as the width of chamber, the relative height reduces to 0.5. The value is reducing when the excavation goes on and finally steadied at 0.38.更多还原