海口某红色粘土基坑数值模拟及本构模型分析

发布时间：2019-02-14 09:32

【摘要】：近年来,我国城市化建设高速发展,各种深大基坑不断涌现,越来越多由基坑开挖引起的安全事故也倍受人们关注。海口市作为海南省省会,是海南国际旅游岛发展的重中之重,其城市建设力度不断加大,同样存在着许多与基坑工程有关的难题。而海口地区广泛分布的海陆交互相红色粘性土是基坑设计、施工最常遇到的地基土之一,因此有必要针对该区域这种典型土质的基坑工程做相关研究。本文在总结前人基坑工程研究成果的基础上,以海口某红色粘土基坑为研究对象,通过土工试验、现场监测和有限元数值模拟相结合的方式,基于不同本构模型完成了对该基坑的数值分析,建议了适用于该地区此类红色粘土基坑的本构模型和相应的参数取值方法。本文主要研究工作和结论如下： (1)针对基坑范围内的海陆交互相红色粘性土进行了一系列的土工实验,获得了试样的物理力学性质指标。 (2)选取Mohr-Coulomb、Drucker-Prager和修正剑桥模型这三种常用本构关系,确定了现场土样的相关参数；并推导了基于土体塑性指数估算修正剑桥模型参数的计算公式。 (3)分别使用三种不同本构模型对海口某红色粘土基坑工程进行了数值模拟。结果表明：三种本构关系下基坑开挖的影响范围相似,但支护桩位移形式、坑内土体隆起变化、坑外地表位移均具有较大差别。 (4)基于该基坑的施工监测数据,获得了土体与支护结构变形的分布规律。与有限元模拟结果对比表明,修正剑桥模型的计算结果和实际值比较接近,更适用于该类红色粘土基坑的数值模拟分析。 (5)对比了不同有限元软件当基坑土体采用修正剑桥模型时的数值分析。通过调整参数,拟合出与实测值相吻合的数值计算结果,并获得了可由地勘报告确定本构参数的计算公式。
[Abstract]:In recent years, with the rapid development of urbanization in China, a variety of deep and large foundation pits have been emerging, and more safety accidents caused by excavation have been paid more and more attention. As the provincial capital of Hainan Province, Haikou City is the most important part of the development of Hainan International Tourism Island. The widely distributed red clay is one of the most common foundation soils in foundation pit design and construction, so it is necessary to do some research on the foundation pit engineering of this typical soil in Haikou area. On the basis of summarizing the previous research results of foundation pit engineering, this paper takes a red clay foundation pit in Haikou as the research object, and combines the method of geotechnical test, on-site monitoring and finite element numerical simulation. The numerical analysis of the foundation pit is completed based on different constitutive models, and the constitutive model and the corresponding parameter selection method for this kind of red clay foundation pit in this area are suggested. The main work and conclusions of this paper are as follows: (1) A series of geotechnical experiments have been carried out on the sea-land cross red clay in the area of foundation pit, and the physical and mechanical properties of the samples have been obtained. (2) three kinds of constitutive relations, Mohr-Coulomb,Drucker-Prager and modified Cambridge model, are selected to determine the relevant parameters of soil samples in situ, and the formulas for estimating the parameters of modified Cambridge model based on soil plasticity index are derived. (3) three different constitutive models were used to simulate a red clay foundation pit in Haikou. The results show that the influence range of excavation is similar under the three constitutive relations, but the displacement of supporting pile, the uplift of soil in the pit and the surface displacement of the pit are all different. (4) based on the construction monitoring data of the foundation pit, the distribution law of the deformation of soil and supporting structure is obtained. Compared with the finite element simulation results, the calculated results of the modified Cambridge model are close to the actual values and are more suitable for the numerical simulation analysis of this kind of red clay foundation pit. (5) the numerical analysis of different finite element software is compared when the soil is modified by Cambridge model. By adjusting the parameters, the numerical results are fitted in agreement with the measured values, and the formula for determining the constitutive parameters from the geological prospecting report is obtained.
【学位授予单位】：海南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU470

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