洞庭湖软土蠕变特性研究

发布时间：2018-01-11 22:23

本文关键词：洞庭湖软土蠕变特性研究　出处：《长沙理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：以洞庭湖地区软土为研究对象,进行大量的室内土工试验,对该地区软土的物理力学参数进行统计分析,并以常规三轴蠕变试验为基础,研究洞庭湖软土的蠕变特性。得出了如下研究成果：(1)通过大量室内土工试验,得到了洞庭湖地区软土的物理力学指标。并运用最小二乘法,将各指标间的相互关系进行分析,求得指标之间的回归方程,为洞庭湖地区软土地基上进行工程建设提供技术参数。(2)在不同加载方式下进行室内常规三轴蠕变试验,得出了不同加载方式下软土的蠕变曲线。通过对比分析表明：围压越大,软土蠕变变形越小,围压越小,软土蠕变变形越大,在相同围压下,等差加载方式产生的蠕变变形明显小于等比加载方式的蠕变变形。(3)通过对围压为100kPa时在等差加载方式下的软土蠕变曲线进行分析,采用麦钦特模型进行拟合,发现该模型因无蠕变稳定阶段而不适合于描述洞庭湖软土蠕变特性。采用传统的西原模型拟合,低于临界应力值的偏应力水平作用时,存在同一问题。因此,本文提出了对低于临界应力值的西原模型进行修正,即在传统西原模型中增加一个宾哈姆体描述蠕变稳定阶段,该修正的西原模型适合于描述洞庭湖软土的蠕变特性。(4)通过工程实例分析,修正西原模型能较好地预测洞庭湖地区软土路基的沉降过程,验证了修正西原模型的合理性,能准确描述洞庭湖软土蠕变特性。
[Abstract]:Soft soil in Dongting Lake area as the research object, indoor geotechnical tests, statistical analysis of physical and mechanical parameters of soft soil in this area, and the conventional three axis creep test, the creep properties of Dongting Lake soft soil. The results of the research results are as follows: (1) through a large number of indoor soil test the physical and mechanical indexes of soft soil in the Dongting Lake area. And by the least square method, the relationship between each index were analyzed, obtained the regression equation between the indexes, to provide technical parameters for the soft soil foundation in Dongting Lake area on the construction of the project. (2) indoor conventional three axis creep test under different loading modes the creep curves of soft soil under different loading modes are obtained. Through the comparative analysis showed that the increase of confining pressure, soft soil creep deformation is small, the smaller the pressure, the soft soil creep deformation is large, under the same confining pressure, loading arithmetic Creep deformation mode is significantly less than the creep loading geometric deformation. (3) through the analysis of the confining pressure of soft soil creep curves in arithmetic load of 100kPa, the merchant model, found the model because there is no stable creep phase and not suitable for describing the creep characteristics of soft soils in Dongting Lake. The Xiyuan model fitting tradition, below the critical stress value of the partial stress level, has the same problem. Therefore, this paper puts forward to Xiyuan model is lower than the critical value of the stress was modified, that is adding a Bingham material in traditional Nishihara model describe the creep steady stage, the creep characteristics of the West the original model is suitable for describing the Dongting Lake soft soil amendment. (4) through the analysis of engineering example, modified Xiyuan model can better predict the settlement process of soft soil subgrade in the Dongting Lake area, verify the modified Nishihara model is reasonable It can accurately describe the creep properties of Dongting Lake soft soil.

【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU447

【共引文献】