考虑桩侧土性参数变化影响的灌注桩竖向承载特性分析

Vertical bearing characteristic analysis of cast-in-place pile considering the influence of soil property parameters on pile side

为研究灌注桩成孔开挖过程导致的桩侧土体弹性模量弱化对桩基承载特性的影响,利用有限元分析软件ABAQUS构建了10组竖向受荷单桩承载特性数值模型,结合桩顶荷载-位移曲线、桩身轴力变化曲线、桩端荷载-沉降曲线,分析了竖向荷载作用下桩周土体内摩擦角与桩侧土体弹性模量对桩基承载特性的影响。结果表明:当桩周土体内摩擦角和桩侧土体弹性模量变化时,桩端荷载-沉降曲线与桩顶荷载-位移曲线趋势均大致相同;在同一竖向荷载作用下,桩顶竖向位移与桩端竖向位移均随着桩周土体内摩擦角和桩侧土体弹性模量的增大而减小;当桩顶竖向位移相同时,桩顶竖向荷载随着桩周土体内摩擦角和桩侧土体弹性模量的增大而增大,桩基承载力与桩周土体内摩擦角和桩侧土体弹性模量呈正相关;桩身轴力均先大致呈线性递减后再保持不变;当桩顶竖向荷载相同时,同一桩身深度下的桩身轴力随桩侧土体弹性模量的减小而增大,而桩侧土体弹性模量对桩侧摩阻力不发挥作用的位置无明显影响;桩周土体内摩擦角对同一桩身深度下的桩身轴力与桩侧摩阻力不发挥作用的位置不敏感。

In order to study the influence of the weakening of the elastic modulus of the soil at the pile side on the bearing characteristics of the pile foundation caused by the process of hole-forming and excavation of the cast-in pile,this paper used the finite element software ABAQUS to construct 10 sets of numerical models of the bearing characteristics of the vertically loaded monopile,and combined the pile top load-settlement curves,the pile axial force curves,and the pile end load-settlement curves to analyze the influence of the internal friction angle in the soil surrounding the pile and the elasticity modulus of the soil on the pile side bearing characteristics under the action of vertical load.The results show that when the internal friction angle in the soil surrounding the pile and the elasticity modulus of the soil on the pile side change,the trends of the load-settlement curve at the pile end and the load-settlement curve at the top of the pile are more or less the same.Under the same vertical load,the vertical displacement of the pile top and the vertical displacement of the pile end decrease as the internal friction angle of the soil surrounding the pile and the elasticity modulus of the soil on the pile side increase.When the vertical displacement of the pile top is the same,the vertical load of the pile top increases with the increase of the internal friction angle in the soil surrounding the pile and the elasticity modulus of the soil on the pile side,and the bearing capacity of pile foundation is positively correlated with the internal friction angle in the soil surrounding the pile and the elasticity modulus of the soil on the pile side.The axial force of the pile body decreases roughly linearly first and then stays unchanged.When the vertical load at the top of the pile is the same,the axial force of the pile body at the same pile depth increases with the decrease of the elasticity modulus of the soil on the pile side,while the elasticity modulus of the soil on the pile side has no significant effect on the position of the pile lateral friction force not to be exerted.The internal friction angle in the soil surrounding the pile is insensitive to the fact that the pile axial force does not play a positional role in relation to the pile lateral friction force at the same pile depth.