深厚回填土中桩基承载性能的数值模拟研究

Numerical Simulation Study on Bearing Capacity of Pile Foundation in Deep Backfill Soil

基于工程实例对深厚回填土中单桩的承载性能进行数值模拟,研究桩端土层弹性模量变化时单桩受力与变形特性的变化情况,得出以下结论:桩端土层弹性模量与深厚回填土中单桩桩身负摩阻力、轴力和桩身中性点深度成正比。桩端土弹性模量由8 MPa增加到300 MPa时,桩身负摩阻力增大了115%,桩身最大轴力增大了85%,中性点深度比由0.35增加到0.75,桩顶最终沉降减小了66%。回填土的厚度与单桩负摩阻力、轴力和桩身中性点深度成正比。

Based on an engineering example,the bearing capacity of a single pile in deep backfilled soil is numerically simulated to study the variation of the stress and deformation characteristics of a single pile when the elastic modulus of soil layer and the thickness of backfilled soil change.The following conclusions are drawn:the elastic modulus of the soil layer at the pile tip is directly proportional to the negative friction resistance,axial force and neutral depth of the pile in the deep backfill soil.When the elastic modulus of soil at the pile tip increased from 8 MPa to 300 MPa,the negative friction resistance of the pile increased by 115%,the maximum axial force of the pile increased by 85%,the neutral depth ratio increased from 0.35 to 0.75,and the final settlement of the pile tip gradually decreased by 66%.The thickness of backfill is directly proportional to negative friction,axial force and neutral depth of pile.