人工冻结黏土承载力模型试验及数值模拟分析

MODEL TEST AND NUMERICAL SIMULATION OF BEARING CAPACITY OF ARTIFICIAL FROZEN CLAY

在天然冻土地区进行工程建设需研究冻土地基承载力。在人工冻结黏土蠕变试验的基础上建立广义开尔文模型,通过改造人工冻土大型冻结试验平台,进行人工冻结黏土地基承载力试验,发现载荷–沉降曲线可以分为3个阶段,基础呈局部剪切破坏。在ANSYS中将考虑相变的温度场转化为温度载荷施加在三维实体模型上,并将广义开尔文模型应用于软件中,采用增量加载方式分级加载。对比数值模拟与模型试验结果,发现地基载荷–沉降曲线规律一致,极限承载力大小基本相等,基础破坏模式相同。结果表明ANSYS软件可以分析复杂边界、初始条件下冻土材料的性质,且能得到不同载荷下冻土材料的应力、位移、塑性区发展状况。

This paper studies the bearing capacity of the frozen soil foundation of engineering constructions in permafrost areas. Based on the creep tests of the artificial frozen clay, a generalized Kelvin model is established. The large-scale artificial frozen soil freezing test platform is used to test the bearing capacity of the artificial frozen clay. It is found that the load-settlement curve could be divided into three stages, and the foundation sees a local shear failure. For the use of the ANSYS, the temperature field with consideration of the phase transition is transformed into a temperature load and a three-dimensional solid model and a generalized Kelvin model are built, with a step loading. By comparing the numerical simulation results and the model test results, it is found that the load-settlement curve is consistent, the ultimate bearing capacity is basically the same, and the basic failure mode is the local shear failure. The results show that the ANSYS could analyze the properties of the frozen soil under complex boundary and initial conditions, and the stress and displacement of the frozen soil under different loads could be obtained.