洞庭湖区软土抗剪强度特性及本构模型研究

发布时间：2018-04-21 22:50

本文选题：洞庭湖区软土 + 抗剪强度　；参考：《湖南科技大学》2017年硕士论文

【摘要】：随着洞庭湖区高速公路和铁路的建设,对洞庭湖区软土现有的研究已经难以满足工程建设需求,为此,本文以南(南阳)益(益阳)高速公路软土路基饱和软土为研究对象,通过室内土工试验和数值模拟分析,对洞庭湖区软土的抗剪强度特性和本构模型进行了一系列研究,主要工作包括以下方面:(1)洞庭湖区软土的工程特性研究。在总结洞庭湖区软土已有的工程特性研究的基础上,进行了一系列的基本物理力学性质试验,求得洞庭湖区软土的物理力学参数,然后对各物理力学参数间相关性进行了研究和分析,拟合了洞庭湖区软土各物理力学参数之间的回归方程,用以指导实际工程。(2)洞庭湖区软土抗剪强度增长规律试验研究。针对洞庭湖区公路软土路基的稳定性问题,通过进行大量室内单向压缩固结试验和直剪试验,研究了在不同固结压力、不同固结度下,洞庭湖区软土抗剪强度指标c、(?)的变化规律,给出固结度和固结压力与抗剪强度指标之间的拟合公式,为洞庭湖地区公路软土路基的设计和施工提供参考依据。(3)洞庭湖区软土应力应变关系试验研究。以洞庭湖区软土为研究对象,利用GDS非饱和土三轴仪进行固结不排水剪切试验和固结排水剪切试验,研究了洞庭湖区软土的强度和变形特征。(4)洞庭湖区软土本构模型研究。对修正剑桥模型理论进行论述,然后在室内土工试验的基础上对适用于洞庭湖区软土的修正剑桥模型参数进行计算;基于ABAQUS有限元程序,对三轴排水剪切试验和三轴不排水剪切试验进行模拟,通过对比数值模拟结果和实际测试数据,分析比较修正剑桥模型对洞庭湖软土的适用性,并分析修正剑桥模型参数取值的影响。
[Abstract]:With the construction of highway and railway in Dongting Lake area, the existing research on soft soil in Dongting Lake area has been difficult to meet the needs of engineering construction. Therefore, this paper takes the saturated soft soil of soft soil subgrade of South (Nanyang) Yi (Yiyang) Expressway as the research object. A series of studies on shear strength and constitutive model of soft soil in Dongting Lake region are carried out by means of laboratory geotechnical tests and numerical simulation. The main work includes the following aspects: 1) the engineering characteristics of soft soil in Dongting Lake region. On the basis of summarizing the existing engineering characteristics of soft soil in Dongting Lake region, a series of basic physical and mechanical properties tests are carried out, and the physical and mechanical parameters of soft soil in Dongting Lake region are obtained. Then, the correlation between physical and mechanical parameters is studied and analyzed, and the regression equation between physical and mechanical parameters of soft soil in Dongting Lake region is fitted to guide the experimental study of shear strength growth law of soft soil in Dongting Lake region. Aiming at the stability of soft soil subgrade of highway in Dongting Lake region, a large number of indoor unidirectional compression consolidation tests and direct shear tests were carried out to study the shear strength index of soft soil in Dongting Lake region under different consolidation pressures and different consolidation degrees. A fitting formula between consolidation degree, consolidation pressure and shear strength index is given, which provides a reference basis for the design and construction of soft soil subgrade in Dongting Lake area. The experimental study on stress-strain relationship of soft soil in Dongting Lake region is carried out. Taking the soft soil in Dongting Lake region as the research object, the undrained shear test and the consolidated drainage shear test were carried out by using GDS unsaturated soil triaxial instrument. The strength and deformation characteristics of soft soil in Dongting Lake region were studied. The constitutive model of soft soil in Dongting Lake region was studied. The modified Cambridge model theory is discussed, and then the parameters of the modified Cambridge model suitable for soft soil in Dongting Lake region are calculated on the basis of indoor geotechnical tests, and based on ABAQUS finite element program, The triaxial drainage shear test and triaxial undrained shear test are simulated. The applicability of the modified Cambridge model to Dongting Lake soft soil is analyzed and compared by comparing the numerical simulation results and the actual test data. The influence of modified Cambridge model parameters is analyzed.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU447

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