砂井地基的一个简化计算模型

A Simplified Computation Model for Sand Well Foundations

基于三维有限元方法,提出了一个预测和评价砂井地基的简化计算模型。该计算模型采用块体单元模拟砂井周围的土体,用砂井单元模拟砂井的竖向排水和水平排水过程,并且推导了反映土体单元和砂井单元之间排水过程的连续性方程。克服了以往有限元法计算砂井地基时,需要将砂井和周围土体作均质化等价的缺点,并可用弹塑性模型反映砂井周围土体的非线性变形和强度特性。计算了单个砂井地基固结排水过程,通过和理论解的比较表明,用本文简化计算模型得到的结果和理论解比较接近。同时,还计算了日本某高速公路路基用砂井+堆载预压法处理的过程,通过分析表明,该简化模型能反映砂井地基的固结排水过程,可以应用于实际工程。

Based on 3D finite element method, a simplified computation model of sandwell considering 3D draining procedure was presented. The computation model is contained by solid elements to simulate the soil around the sandwell and sandwell elements to simulate the horizontal and vertical drainage of sandwell. The continuous equation representing drainage process between a soil element and a sandwell element was also presented. It overcomes the shortcomings of conventional equivalent models which used to simulate sandwell foundations. It can also employ a 3D elastoplastic soil model to evaluate the stress-strain behavior of clay soils around the sandwell. The consolidation problem of a single sandwell was calculated by using the proposed computation model and the result is closed to that of the theoretical calculatoin. Furthermore, this computation model was applied to assess the settlement and consolidation of a Japanese highway soft foundation which use of sandwell and surcharge method. Results show that the model can represent the process of consolidation of sandwell ground and it is applicable to practical problems.