桩周土开挖条件下桩基础承载特性数值分析

The pile bearing capacity analysis under excavation conditions

运用桩基础支撑上部既有建筑物地下增层的过程中,随着桩周土减少和桩基础的暴露,桩的承载特性会出现明显变化。文章运用ANSYS有限元程序分析了桩周土开挖前、后以及不同开挖深度等工况下,桩基础承载特性的变化规律。结果表明:随着桩周土开挖深度增大,被开挖段的桩身侧阻力消失,需要增加未开挖部分桩身侧阻力、桩端阻力来增强桩身轴力。同时,也需增大桩基沉降量和桩土间的滑移量。

The underpinning pile can be used to support the existing building for construction of basement.The soil excavation around the pile caused the piles side resistance redistribution.By using ANSYS finite element analysis program,the paper analyzes the bearing characteristics of pile foundation under the conditions before and after excavation of the soil around the pile and in different depths.The results show,with the increase of excavation depth,pile side friction resistance undigged disappeans.The side resistance and end resistance of the pile without excavation needs to be increased to enhance the axial force of pile.At the same time,the pile settlement amout and slip amount between pile and soil needs to be increased.