基于光纤技术和有限元计算的灌注桩承载特性

Bearing Characteristics of Cast-in-place Piles Based on Optical Fiber Technology and Finite Element Calculation

为了掌握灌注桩的承载力及桩身受力分布和传递规律,开展了灌注桩现场静载试验,并使用光纤传感器对灌注桩桩身变形进行了测试,获得了桩身应变信息。采用有限元软件ABAQUS,开展了灌注桩承载特性数值模拟研究。结果表明,静载试验得到的桩基荷载-位移(Q-S)曲线和数值模拟测得的桩基Q-S曲线基本一致;光纤传感器所得结果显示桩身轴力在桩头处是最大的,随着桩长增加而逐渐递减,整体变化规律与数值模拟结果规律一致;灌注桩实测桩身侧摩阻力沿桩长变化规律与数值模拟得到的受力分布和传递基本一致,验证了有限元计算模型中选取的参数是合理的。考虑了桩长、桩径和桩土界面摩擦因数对桩基Q-S曲线、桩身轴力分布和侧摩阻力分布的影响,桩径和桩土界面摩擦因数对桩基的Q-S曲线、桩身轴力分布和侧摩阻力分布的影响很大,而桩长的影响较小。

In order to grasp the bearing capacity,the distribution and transfer law of the force of the cast-in-place pile,the static load test of the cast-in-place pile was carried out,the optic fiber sensor was used to monitor the deformation of the cast-in-place pile,the strain information of the pile was obtained.Using the finite element software ABAQUS,the numerical simulation study on the bearing characteristics of cast-in-place pile was carried out.The results show that the Q-S curve of the pile foundation obtained by the static load test is basically consistent with the Q-S curve of the pile foundation obtained by the numerical simulation.The results of optic fiber sensor show that the axial force of the pile is the largest at the pile head,and gradually decreases with the pile length increasing,the overall change law is consistent with the numerical simulation results.The variation law of measured shaft side friction cast-in-place pile along the pile length is basically consistent with the force distribution and transmission of pile obtained by numerical simulation,it verifies that the parameters selected in the finite element calculation model are reasonable.The influence of pile length,pile diameter and friction coefficient of pile-soil interface on Q-S curve of pile foundation,axial force distribution of pile shaft and lateral friction distribution are considered.The influence of pile diameter and friction coefficient of pile-soil interface on Q-S curve of pile foundation,the influence of pile diameter and friction coefficient of pile-soil interface is great,while the influence of pile length is small.