土壤垂直和水平复合载荷-变形关系研究

基于有限元理论分析了土壤在承受垂直和水平复合载荷下的变形规律。首先通过平板沉陷试验分析确定土壤在垂直载荷作用下的载荷-变形关系,接着考虑水平载荷的影响,通过剪切试验确定土壤的复合载荷-变形关系。研究结果表明,水平载荷会造成土壤的滑动沉陷,水平剪切位移与土壤的滑动沉陷量之间呈线性关系。对影响滑动沉陷量的因素进行了分析,其中影响比较大的因素是垂直方向的载荷以及土壤的塑性参数:黏聚力和摩擦角,而土壤的弹性参数:弹性模量和泊松比对滑动沉陷量的影响比较小。

Composite Load-deformation Relationship of Soil under Vertical and Lateral Loads

The research of composite load-deformation relationship of soil under vertical and lateral loads is the difficulty in vehicle terramechanics field now. The lateral load causing slide sinkage was put forward by some scholars in the past but the numerical relationship between lateral load and slide sinkage was not clear yet. The deformation law of soil under vertical and lateral loads was analyzed on the base of finite element theory. Firstly, the soil stress-strain characteristics was analyzed and the modified drucker-prager cap model was chosen as the constitutive model of soil considering the soil elastic behavior, yield criterion, hardening law, flow rule and failure criterion. Then the load-deformation relationship of soil under vertical load was analyzed in the way of relationship between plate sinkage and pressure by the plate-sinkage test. Finally, the composite load-deformation relationship of soil under vertical and lateral load was analyzed considering the lateral load influence by the shear test on the base of load-deformation relationship of soil under vertical load. The lateral load could cause the increase of sinkage in the vertical direction, divided the total sinkage into static load sinkage and slide sinkage, it can be found that the lateral load can cause the slide sinkage and there was a linear relationship between shear displacement and the slide sinkage. The influence factors to the value of slide sinkage were analyzed and the major factors that affected the value of sinkage were vertical load and soil plastic parameters such as soil cohesion and frication angel, the soil elastic parameters such as elastic modulus and passion ratio had little effect on the value of sinkage. The linear relationship between shear displacement and slide sinkage of soil was clearly put forward and it can be used to calculate the soil bearing characteristics more accurately in vehicle terramechanics and other research fields involved soil deformation.