摘要
通过分析室内模型试验和数值模拟成果发现,随着荷载的不断增加,大桩帽刚性短桩桩帽下地基土体最终发生侧向整体剪切滑移破坏,而下部桩体则发生向下刺入破坏。据此,提出了一种滑块位移法分析桩帽下地基土体的荷载-位移关系,而下部桩体的荷载-位移关系则采用荷载传递法进行分析。然后,基于上、下两部分的位移协调条件,叠加得到大桩帽刚性短桩的荷载-位移关系曲线(P-s曲线)。同时,采用模型试验结果对此方法进行了验证,结果表明,采用此方法得到的P-s曲线与试验结果吻合良好。最后,利用本文计算模型分析了不同的帽桩直径比D/d以及桩长与桩帽直径比L/D对大桩帽刚性短桩承载力的影响,结果表明,在软土地基中宜采用帽桩直径比D/d>2和桩长与桩帽直径比L/D<10的带帽桩。
Model tests and numerical simulations were carried out to investigate load transfer characteristics of short stiff piles with big caps. With increasing loads, the lateral shear slip damage occurred on ground soil underlying the pile cap, whereas punching shear was found in the vicinity of the pile tip for soft foundation reinforced by short stiff pile with a large cap. Thus, a novel block displacement method was proposed to analyse the load-displacement relationship of ground soil underlying the pile cap, and the load transfer method was put forward for the lower part of the pile. Based on the displacement compatibility of the upper and lower parts for a single pile, the load-displacement relation（P-s curve） for the short stiff pile with the large cap was obtained by using the iteration method. Meanwhile, the calculated P-s curves were compared with the measured results in model tests, which showed a good agreement between them. Furthermore, the presented calculation model investigated the effects of pile cap-body diameter ratio D/d as well as the ratio between the pile length and pile cap diameter L/D on the bearing capacity of the short stiff pile with large pile cap. The results demonstrated that suggested ranges were D/d〉2 and L/D〈10 for the application of pile reinforced soft foundation with pile caps.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2017年第12期3410-3418,共9页
Rock and Soil Mechanics
基金
国家重点研发计划(No.2016YFC0800203)
国家自然科学基金项目(No.51278186)~~
关键词
复合地基
滑块位移法
带帽桩
P-S曲线
荷载传递法
composite foundation
block displacement method
pile with cap
P-s curve
load transfer method
