层状岩体开洞地基稳定性分析

发布时间：2018-04-23 19:29

本文选题：开洞地基 + 层状岩体　；参考：《重庆大学》2014年硕士论文

【摘要】：在社会不断发展和国家城市化发展战略的推进下，城市化进程迅速加快，地面与地下空间综合利用成为发展重点。在重庆，地表高楼林立，地下防空洞、地铁隧道、大型地下商场众多。随着时代发展，势必面临地面建筑的改建，拆迁，再建等工程，这些工程由于地下洞室的存在，既要考虑到上部建筑的稳定性，又要考虑洞室的稳定性，如果洞室出现稳定性问题，则影响建筑基础，而基础直接影响上部建筑，此即为洞室地基稳定性问题，是地面地下空间综合开发利用需要考虑的重点问题。而占世界陆地面积达2/3的层状岩体由于其明显的各向异性特点以及复杂的破坏机制更为这些工程的安全进行增加了复杂性。因此本文利用能够比较好的反映层状岩体力学特性及破坏模式且易应用于工程实际的Ubiquitous-Joint本构模型分析了在不同荷载位置以及不同层理参数下层状岩体开洞地基稳定性。论文的主要内容和结论有： ①从理论和实践的角度出发，总结分析了层状围岩洞室的失稳机理及破坏模型，表明层状围岩洞室的破坏模式及形态与其层理倾角等层理特性密切相关。同时，洞室地基的稳定性涉及建筑地基和洞室围岩两者的稳定性，，论文分别总结了两者的稳定性判据，整体作为洞室地基的稳定性判据。 ②论文总结并比较了层状岩体常用的计算模型，因为Ubiquitous-Joint能够比较好的模拟层状岩体洞室围岩的各向异性特点及破坏模式，以及便于应用的特点，本文选取Ubiquitous-Joint本构模型分析洞室地基的稳定性。 ③运用有限差分法，开展层状岩体开洞地基动态数值模拟分析，将洞室开挖后的结果与传统的Mohr-Coulomb本构计算结果进行比较，表明Ubiquitous-Joint本构能比较好的反应层状岩体各向异性的特点。同时，施加上部荷载及改变其位置进行动态分析，结果表面荷载位置对洞室受力变形有一定影响，荷载位置不同应力变形传递路径有所不同，破坏形式有所改变。 ④以层理摩擦角、层理粘聚力、层理倾角和层理抗拉强度作为4因素，以洞顶、地表及边墙相对变形作为评价指标，开展4因素4水平的正交试验，并对试验数据进行极差分析和方差分析，在此基础上进行单因素敏感性分析，总结层理特性对洞室地基稳定性的影响，计算结果表明，层理参数对洞室地基的稳定性影响较大，各有不同。 ⑤将Ubiquitous-Joint本构模型运用于东大门隧道上方修建培训综合楼工程，通过基坑开挖和建筑荷载分步施加的动态施工模拟，分析了在东大门隧道上方修建培训综合楼时洞室地基的受力变形特点及其稳定性，并与监测资料进行比较，计算结果与监测数据一致，洞室地基安全稳定。
[Abstract]:With the development of society and the development strategy of urbanization, the process of urbanization is speeding up rapidly, and the comprehensive utilization of surface and underground space becomes the key point of development. In Chongqing, the surface tall buildings, underground bomb shelters, subway tunnels, large underground shopping malls. With the development of the times, we are bound to face the reconstruction, demolition, reconstruction and other projects of ground buildings. Due to the existence of underground caverns, these projects should not only take into account the stability of the upper buildings but also the stability of the caverns. If the stability of the cavern appears, it will affect the foundation of the building, and the foundation directly affects the upper building, which is the stability problem of the foundation of the cave, which is the key problem that needs to be considered in the comprehensive development and utilization of the surface and underground space. Because of its obvious anisotropy and complex failure mechanism, the layered rock mass, which accounts for 2 / 3 of the world's land area, increases the complexity of the safety of these projects. In this paper, Ubiquitous-Joint constitutive model which can reflect the mechanical characteristics and failure mode of layered rock mass and is easy to be applied to engineering practice is used to analyze the stability of layered rock mass foundation with different load positions and different bedding parameters. The main contents and conclusions of the paper are as follows: 1. From the angle of theory and practice, the failure mechanism and failure model of layered surrounding rock cavern are summarized and analyzed. It is shown that the failure mode and morphology of layered surrounding rock cavern are closely related to the bedding characteristics such as bedding dip angle. At the same time, the stability of the cavern foundation is related to the stability of both the building foundation and the surrounding rock. (2) the paper summarizes and compares the commonly used calculation models of layered rock mass, because Ubiquitous-Joint can simulate the anisotropic characteristics and failure mode of the surrounding rock mass of layered rock mass, and it is easy to be applied. In this paper, Ubiquitous-Joint constitutive model is chosen to analyze the stability of cavern foundation. 3 using finite difference method, the dynamic numerical simulation analysis of layered rock opening foundation is carried out, and the results after excavation are compared with the traditional Mohr-Coulomb constitutive calculation results. It shows that Ubiquitous-Joint constitutive law can well reflect the anisotropy of layered rock mass. At the same time, the dynamic analysis is carried out by applying the upper load and changing its position. The results show that the surface load position has a certain influence on the stress and deformation of the cavern, the different stress and deformation transfer paths are different in the load position, and the failure form is changed. (4) taking bedding friction angle, bedding cohesion, bedding dip angle and bedding tensile strength as four factors, taking the relative deformation of roof, surface and side wall as evaluation index, the orthogonal experiments of 4 factors and 4 levels are carried out. On the basis of the range analysis and variance analysis of test data, single factor sensitivity analysis is carried out, and the influence of bedding characteristics on the stability of cavern foundation is summarized. The calculation results show that the bedding parameters have great influence on the stability of cavern foundation. Each is different. (5) the Ubiquitous-Joint constitutive model is applied to the construction of training complex building above the Dongmen tunnel, and the dynamic construction simulation is carried out through excavation of foundation pit and application of building load step by step. This paper analyzes the mechanical deformation characteristics and stability of the cavern foundation when the training complex building is built above the Dongmen tunnel, and compares with the monitoring data. The calculated results are consistent with the monitoring data, and the cavern foundation is safe and stable.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU470

【参考文献】