挤扩支盘桩抗拔承载性能试验研究与数值分析

为进一步探讨挤扩支盘桩的承载性能及桩土相互作用机理,依托输电线路实际工程,开展了挤扩支盘桩上拔现场静载试验及有限元数值模拟,得到了支盘桩单桩抗拔承载性能,分析了支盘桩荷载传递规律、桩周土体变形规律、桩土相对位移变化情况等,探讨了支盘数量、支盘间距及水平荷载对支盘桩抗拔承载力的影响规律。结果表明:同等条件下单盘支盘桩抗拔承载力比等径灌注桩提高15.3%;轴力分布曲线及桩土相对位移在支盘位置发生突变;塑性应变主要发生在支盘上部的土体中;水平荷载的存在能提高支盘桩的抗拔承载力;一定范围内支盘桩的抗拔承载力随支盘数量及支盘间距的增加而增大,支盘间距不宜小于2.5倍支盘直径,在实际工程应用时,应予以考虑,合理确定支盘的数量或支盘间距。

Field test study and numerical simulation on uplift bearing capacityof squeezed branch pile

In order to further reveal the load carrying capacity and interaction mechanism between piles and soil, the static load test and finite element numerical simulation of the squeezed branch pile were carried out based on transmission line engineering. The bearing capacity, load transfer law of the squeezed branch pile, deformation law of soil around the pile and the relative displacement of pile and soil were analyzed, and the influence of the number and the spacing of plates and the horizontal load on the uplift bearing capacity was discussed. The results showed that the uplift bearing capacity of branch pile improved 15.3% higher than that of equal diameter pile under the same conditions; the axial force distribution curve and the relative displacement between pile and soil changed obviously in the position of the plate; the plastic strain mainly occurs in the soil upper the plate; the existence of horizontal load can improve the uplift bearing capacity; the uplift bearing capacity of branch pile increases with the increase of the number and the spacing of the supporting plate, and the spacing of the supporting plate is not less than 2.5 times the diameter of the supporting plate, so that they should be considered and determined reasonably in engineering application.