循环荷载下天津软黏土不排水强度弱化模型研究及应用

发布时间：2018-02-14 22:49

本文关键词： 软黏土循环荷载不排水强度弱化模型二次开发　出处：《天津大学学报(自然科学与工程技术版)》2015年04期 　论文类型：期刊论文

【摘要】：波浪等循环荷载作用下,饱和软黏土产生超孔隙水压力,土体强度弱化,导致地基承载力和防波堤等近海结构稳定性降低.基于土体强度弱化的原理,建立一种表示土体不排水强度在不同动应力水平下随循环荷载作用次数变化的强度弱化模型.模型通过建立软黏土不排水强度与孔隙水压力增长规律的关系,表示出软黏土不排水强度弱化的具体过程.在有限元软件ABAQUS上进行二次开发,对天津港防波堤地基软黏土的动、静三轴试验进行数值模拟运算,并与试验数据对比.结果表明,文中建立的强度弱化模型简单准确,能够较好地表示土体不排水强度弱化过程.将模型应用到波浪荷载作用下部分回填换砂处理的软土地基上沉箱结构进行沉降变形分析,并与未考虑土体强度弱化的静力、拟静力有限元分析结果进行对比,研究了强度弱化对结构沉降变形的影响.
[Abstract]:Under the action of wave and equal cyclic load, saturated soft clay produces excess pore water pressure and weakens the strength of soil, which results in the reduction of foundation bearing capacity and stability of offshore structures such as breakwater. A strength weakening model is established to describe the variation of undrained strength of soil with cyclic load under different dynamic stress levels. The relationship between undrained strength of soft clay and pore water pressure is established. The concrete process of weakening the undrained strength of soft clay is indicated. The dynamic and static triaxial tests of soft clay on the foundation of Tianjin Port breakwater are numerically simulated and compared with the test data by the second development of finite element software ABAQUS. The results show that the dynamic and static triaxial tests of soft clay on the foundation of Tianjin Port breakwater are carried out. The strength weakening model established in this paper is simple and accurate and can better represent the weakening process of undrained soil strength. The model is applied to analyze the settlement and deformation of caisson structure on soft soil foundation with partial backfill and sand replacement under wave load. Compared with the results of pseudostatic finite element analysis without considering the weakening of soil strength, the influence of strength weakening on the settlement deformation of the structure is studied.
【作者单位】：天津大学水利工程仿真与安全国家重点实验室;
【基金】：国家自然科学基金资助项目(51279128)
【分类号】：U652.2

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