工程硕士论文-深基坑开挖数值模拟与参数优化研究.docVIP

摘 要 基坑工程面对各种各样的地基土和复杂的环境条件进行施工作业，存在各种不确定因素，所以很难对基坑工程的设计与施工制定一套标准模式，或用一套严密的理论和计算方法，能够把握施工中可能发生的各种变化。 本文首先介绍了目前常用的几种计算基坑受力与变形的方法和有限元理论，在此基础上，对如何将有限元理论应用于基坑工程，以合理地指导设计与施工做了深入的研究。并就以下两方面应用进行实例分析。 ⑴ 基坑的计算与分析。采用有限元方法对基坑工程进行模拟计算。本文对重力式挡墙围护结构基坑工程进行了有限元模拟计算，根据与实际监测资料的对比分析，表明本文所采用有限元方法是合理可行的。另外本文还比较了增量法与全量法计算结果的差异，讨论了桩体刚度、桩土弹性模量、地面超载、土体性质等因素对支护结构的影响，得到了一些可供工程参考的结论。 ⑵ 基坑围护结构的优化设计。本文选取支撑截面尺寸等作为设计变量（DVs），通过改变这些变量的数值来实现结果的优化。同时以测点的内力、位移等作为状态变量（SVs），通过这些变量可以约束设计，以保证基坑工程的安全。最后以整个支撑系统所用混凝土的体积为目标函数，希望计量减小这个数值，以降低工程的造价，最终得到了令人满意的结果。 关键词：深基坑，支护体系，有限元，优化设计 ABSTRACT Because of various foundation conditions and complicated environment， some uncertain factors consist in the constructing of foundation pit， so it is difficult in establishing a suit of standard mode for the design and constructing of foundation pit project， or settling all potential movement in constructing of foundation pit project with a suit of narrow theory and cacluational method. In the first part of this paper， the current calculational methods in common use are introduced，and the main FEM theories are studied， and the characteristic of each theory are analysed， some corresponding improvement is maked. In the second part， how to apply the FEM theories in foundation pit project to guide design and construction is studied， and two main application methods are advanced. ⑴ Calculate and Analyse. Simulate and Calculate the foundation pit project with the bar system FEM or the planar or spacial finite element method. The pile building enclosure with two or three bracing pieces and the gravity retaining wall are particularized as example in this paper. From the antithesis with datum practically measured， it indicates that the FEM which is adopt by this paper is logical and feasible. In addition， in this paper， the calculate results of incremental calculation method and total calculation method are compared； the infection of the piles tiffness、the elastic modulus of soil and pile、the excess load、the soil character to building