饱和砂性土流变模型的试验研究

正确合理的土体本构模型确定是地面沉降模拟的关键之一。上海和江苏地区多年来野外分层标的实际观测资料表明该区含水层系统砂层变形具有流变特征,表现出变形滞后于含水层水位变化的现象。本文基于粘弹性理论,选取了常州含水层系统原状砂性土样进行单轴压缩试验,分析了砂性土流变荷载曲线,并选择现有的相关本构模型进行识别,从而确定能更好反映研究区土体变形规律的流变模型。结果表明,研究区砂性土可采用Burgers模型进行描述,反演获得的4个流变参数随荷载的增加表现出一定的规律性。

UNIAXIAL COMPRESSION TESTS FOR CREEP MODEL OF SATURATED SAND IN CHANGZHOU

A reasonable soil constitutive model is one of the key aspects for the land subsidence simulation. Based on the data from layered marks of Shanghai and Changzhou region, the results indicate that the rheology occurs in the sandy soil. In order to investigate the lag phenomena between the deformation in the land subsidence and the variation of the water level of the aquifer, the creep behavior of the saturated sand is studied based on the uniaxial compression tests of undisturbed soils of the 1st, 2nd confined aquifers in Changzhou City. Based on visco-elastic theory, inverse models of creep curves of load tests were set up for Merchant and Burgers model. The analysis results show that the optimum rheological model is Burgers model for different load test curves. The relation between the rheological parameters and applied normal loads were analyzed and discussed.