交通荷载作用下软土地基的累积沉降分析

An analysis of cumulative settlement of soft soil under traffic loading

针对交通荷载作用下软土地基的累计沉降问题,提出采用土体刚度衰减修正公式计算累计塑形变形的方法.基于饱和软土循环三轴试验数据,建立刚度衰减系数与循环次数间的关系.对有限元软件ABAQUS进行二次开发,将刚度衰减模型嵌入到有限元分析程序中去,再通过数值分析计算出任意循环周数后土体的累积塑性变形.采用该方法对交通荷载作用下典型上海软土地基的累积沉降进行预测.计算结果表明,路面结构层的存在有助于减小软土地基的沉降,交通荷载所引起的沉降主要发生在软土地基的浅层,并且随着深度的增加而迅速减小.

Using a modified stiffness degradation model, a method for calculating the cumulative deforma- tion induced by traffic load was proposed. Firstly, based on the cyclic triaxial test results, the relationship between the degradation index and the number of cycles was built. Then, the stiffness degradation model was embedded into ABAQUS software by secondary development method. And the accumulated plastic de- formation after each cyclic loading could also be obtained. Finally, the new method presented herein was applied to predict the long-term settlement of shanghai soft soil under the traffic load. It is found that the existence of the pavement structure layer can contribute to reduce the settlement of soft soil. The settle- ment due to the traffic load mainly occur in the shallow area of soft soil and decreases quickly along with the increase of the depth.