两种径向多圈层土体平面应变模型的对比

Comparison on two kinds of radial multi-zone plane strain models

针对土体径向非均质性的多弹簧串联的多圈层平面应变模型在严密性及精确度方面存在的不足的情况,提出基于复刚度传递的多圈层平面应变的严格数学力学模型.对多弹簧串联的多圈层平面应变模型和基于复刚度传递的多圈层平面应变模型进行严格的数学论证,论证表明,前者由于数学力学上不严密,无法退化到均质情况下平面应变精确解;而后者由于数学力学上的严密性,可以退化到均质情况下平面应变精确解.分别通过对多工况条件下土体动力响应(土体复刚度)的分析比较,指出前者在只计算低频阶段桩基动力响应的工况能够近似适用,而对需精确考虑阻尼的工况则不适用.

A complex stiffness transfer model which is rigorous and precise on mathematics and physics was given aiming at the shortage of rigor and precision of multi-springs in series plane stain model used to analyze soil radial inhomogeneity. Rigorous mathematical demonstration was evolved for the multi-springs in series plane stain model and the complex stiffness transfer plane stain model. The demonstration results show that the former is not precise enough and cannot degenerate to the plane strain precise solution under the condition of homogeneous soil, but the later is accurate and can degenerate. The comparison of soil dynamic response under the condition of several different soil properties indicate the former is applicable for the pile dynamic response with lower frequency but not applicable for the pile dynamic response which needs to consider the soil damping accurately.