深圳前海软土本构模型的研究及工程应用

发布时间：2018-04-17 23:10

本文选题：基坑开挖 + 隧道保护　；参考：《深圳大学》2017年硕士论文

【摘要】：由于资本投资及土地资源稀缺,地铁沿线将会出现高密度的物业开发,各种高大建筑拔地而起,越来越多的深大基坑将会出现在地铁隧道的周边。深圳广泛分布着深厚的软土,在软土中开挖的深基坑容易遇到诸多工程难题,如基坑容易出现变形过大甚至出现垮塌、倾覆等安全事故,对社会及经济产生重大影响。另外,由于基坑开挖容易诱发周边土体的位移及应力场发生变化,对邻近地铁隧道产生不利影响,进而对隧道的安全运营及结构安全构成威胁。因此在施工前准确分析及预测基坑及隧道的变形将具有重要的意义。有限元数值模拟分析是常用的有效手段,但在计算过程中设计人员往往面临如何选取合的适本构模型及确定合理参数的难题。基于实际需求,本文的主要研究工作如下:(1)以深圳前海区原状软土为试验对象,通过一系列室内试验研究软土的力学特性及测定H-S模型参数,并建立参数之间的相关关系,使得可以从简单室内试验或岩土勘察报告中推算出主要模型刚度参数。同时对比分析试样在侧向卸荷与加载条件下的参考割线模量之间的关系。(2)在前海某基坑开挖的基础上,分别运用不同的本构模型及不同的H-S模型刚度参数建立三维有限元模型进行计算分析,将计算结果与实测结果进行对比,分析模型的适用性。(3)通过从改变支护结构刚度、地下连续墙的厚度及插入比、隧道与基坑的间距、隧道埋深等方面研究了不同因素在基坑开挖过程中对隧道的影响。(4)从“控制基坑变形、阻断变形传递、隧道保护”三方面总结基坑开挖对隧道影响控制的措施,为设计优化及施工提供参考依据。
[Abstract]:Because of the capital investment and the scarcity of land resources, the property along the MTR will be the development of high density, all the tall buildings, the surrounding foundation pit will be more and more appear in the subway tunnel. Shenzhen is widely distributed in deep soft soil, deep foundation pit excavation in soft soil is easy to encounter many engineering problems, such as prone to deformation of foundation pit too large or even collapse, overturning safety accidents, have a significant impact on society and economy. In addition, the displacement of surrounding soil excavation and induced stress field change, have an adverse effect on the adjacent subway tunnels, pose a threat to the safe operation and safety of the tunnel structure. Therefore in the construction of the accurate analysis deformation prediction of foundation pit and tunnel and will be of great significance. The finite element numerical simulation analysis is an effective method used in the calculation process, but the designer How to select the problems often face the constitutive model and determine reasonable parameters. Based on the actual demand, the main research work of this paper is as follows: (1) in Shenzhen District of Qianhai undisturbed soft soil as the research object, through the determination of the parameters of H-S model and mechanical properties of a series of laboratory test on the soft soil, and the establishment of related parameters between the calculated parameters, the stiffness model mainly from simple laboratory test report or geotechnical investigation and comparative analysis. The relationship between the reference specimen unloading secant modulus load and loading conditions on the side. (2) based on the excavation of a foundation pit in Qianhai, respectively, using different constitutive parameters of stiffness model and the H-S model to establish a three-dimensional finite element model for calculation and analysis of calculation results and measured results are compared. The applicability of the model is analyzed. (3) through the change from the supporting structure stiffness, underground continuous The thickness of the wall and the insertion ratio, distance between tunnel and excavation, tunnel depth and other aspects of the influence of different factors on the tunnel in the excavation process. (4) from the "deformation control of foundation pit deformation, block transfer, tunnel protection" three aspects on control measures of tunnel excavation, provide a reference for the optimization design and construction.

【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU447

【参考文献】