结构性花岗岩残积土的试验研究和数值分析

发布时间：2018-04-05 01:31

本文选题：花岗岩残积土　切入点：结构性　出处：《华南理工大学》2015年硕士论文

【摘要】：结构性模型是21世纪岩土工程研究的核心问题。花岗岩残积土是一种典型的结构性土,在华东与华南地区分布较广泛,在工程中经常遇到。但是由于结构性花岗岩残积土的研究还不够深入,远远落后于黄土、膨胀土等特殊土。特别是花岗岩残积土的结构性,会对土体变形产生非常大的影响。为了更加准确的预测工程中结构性花岗岩残积土的变形,避免保守的工程计算导致的人力物力的浪费,结构性花岗岩残积土的研究具有重要的意义。本文在收集了相关文献与了解前人成果的基础上,对花岗岩残积土的研究历程做出了介绍,对研究结构性的方法的发展进行了总结。首先,以深圳某超大深基坑所取的花岗岩残积土为研究对象,通过土工试验,获取土样的基本物理性质参数;通过三轴试验与压缩试验分别对结构性花岗岩残积土的原状土与重塑土进行对比分析,分析土体结构性在花岗岩残积土剪切破坏的表现形式。其次,在试验的基础上对花岗岩残积土的剑桥模型参数进行分析,结构性在剑桥模型中主要表现为破坏线平移以及e-lnp压缩曲线的多段化;利用结构性参数表征结构性对剑桥模型参数的影响,引入到修正剑桥模型当中,建立新的结构性剑桥模型,并进行屈服函数的推导。再次,利用适合岩土工程的ABAQUS软件对结构性剑桥模型进行逐步验证,模拟室内的三轴不排水试验,与传统的MCC模型计算结果进行对比发现,结构性模型更好的反映土体的应变软化,应力-应变关系上也有更高的拟合度。最后,建立深圳某超大深基坑的数值分析模型,利用结构性剑桥模型,对基坑开挖过程进行数值模拟。证明结构性剑桥模型相比MCC模型更能反映工程中的土体变形。
[Abstract]:Structural model is the core of geotechnical engineering research in the 21 st century.Granite residual soil is a typical structural soil, which is widely distributed in East China and South China, and is often encountered in engineering.However, the study of structural granite residual soil is not deep enough and lags far behind the special soil such as loess and expansive soil.In particular, the structure of granite residual soil will have a great impact on soil deformation.In order to predict the deformation of structural granite residual soil more accurately and avoid the waste of manpower and material resources caused by conservative engineering calculation, the study of structural granite residual soil is of great significance.On the basis of collecting relevant documents and understanding the previous achievements, this paper introduces the research course of granite residual soil, and summarizes the development of research methods of structure.Firstly, the basic physical parameters of the soil samples are obtained by the geotechnical test, taking the granite residual soil from a large deep foundation pit in Shenzhen as the research object.By means of triaxial test and compression test, the undisturbed soil and remolded soil of structural granite residual soil were compared and analyzed, and the forms of soil structure in shear failure of granite residual soil were analyzed.Secondly, based on the experiments, the parameters of the Cambridge model of the granite residual soil are analyzed. The structural characteristics in the Cambridge model are mainly the translation of the failure line and the multi-section of the e-lnp compression curve.The influence of structural parameters on the parameters of Cambridge model is represented by structural parameters. The modified Cambridge model is introduced to establish a new structural Cambridge model and the yield function is derived.Thirdly, the structural Cambridge model is verified step by step by using ABAQUS software which is suitable for geotechnical engineering, and the triaxial undrained test is simulated in the laboratory. The results are compared with those of the traditional MCC model.The structural model can better reflect the strain softening of soil, and the stress-strain relationship also has higher fitting degree.Finally, the numerical analysis model of a large deep foundation pit in Shenzhen is established, and the excavation process of the foundation pit is simulated by using the structural Cambridge model.It is proved that the structural Cambridge model can reflect the deformation of soil better than the MCC model.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43

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