基于透明土材料的斜桩承载机理模型试验与数值模拟

Model test and numerical simulation study on bearing mechanism of inclined pile based on transparent soil

针对桩身倾斜影响基桩承载能力的问题,引入粒子图像测速(particle image velocimetry,PIV)技术,设计了透明土可视化模型试验,并对砂土中单根斜桩进行了颗粒流程序(particle flow code,PFC)数值模拟,开展了斜桩承载机理研究。结果表明:在桩体微倾斜时,桩身两侧土体对其摩阻力加大;竖向承载力方面,倾斜度为2%、4%的斜桩>直桩>倾斜度为8%的斜桩;倾斜单桩桩顶水平位移随着桩身倾斜度的增加而逐渐增大;斜桩运动轨迹为沿桩身方向斜向下移动,桩体倾斜引起少量侧移;随着竖向荷载的增加,倾斜度为8%的斜桩的桩底端侧移不变,桩体产生一个大致以桩端为圆心进行的顺时针转动,达到极限荷载时,桩基础发生破坏;不同倾斜度的单桩桩周土体扰动均为上部大于下部,桩身中部土体产生最大侧移。

Aiming at the problem that pile tilt affects the bearing capacity of foundation pile,the particle image velocimetry(PIV)technology was introduced to design transparent soil visualization model test,and the particle flow code(PFC)numerical simulation was carried out on a single inclined pile in sand soil to study the bearing mechanism of inclined pile.The results show that when the pile is slightly inclined,the friction resistance of soil increases on both sides of the pile.The vertical bearing capacity of 2%and 4%inclined pile is greater than that of the vertical pile with a slope greater than 8%.The horizontal displacement of inclined single pile tip increases with the increase of pile inclination.The trajectory of inclined pile is inclined downward along the direction of pile body,and the inclined pile body causes a little lateral movement.With the increase of vertical load,the bottom end of 8%inclined pile moves sideways unchanged,and the pile body rotates clockwise roughly to the center of the pile,reaching the ultimate load untill the pile foundation is destroyed.The soil disturbance in the upper part of the pile is larger than that in the lower part of the pile.