桩顶与承压板新型构造方式下的单桩承载特性

Bearing characteristics of single pile with new construction between pile’s top and bearing plate

首次提出在桩顶黏贴一块10 mm厚的聚苯乙烯泡沫板,并在泡沫板上铺设150 mm厚砂垫层的一种新型构造方式。在山东省东营市伟浩中央花园,通过不同状态下的现场静载荷试验,对竖向荷载作用下,承压板与桩顶新型构造方式下的粉喷桩单桩复合地基以及自由单桩的承载特性进行了对比研究。结果表明:承压板与桩顶新型构造方式下的粉喷桩单桩复合地基承载力比自由单桩承载力增加很多;承压板与桩顶新型构造方式可有效利用土的承载力,减少桩顶应力过分集中,同时可使桩间土压缩提前发生,强化桩土相互作用,使得桩土更趋于整体沉降,达到有效减小工后沉降的目的。

In order to improve the bearing capacity of composite foundation, a new type of construction between the top of pile and bearing plate was proposed for the first time. A polystyrene foam board with the thickness of 10 mm was pasted on the top of pile, and the sand cushion layer with the thickness of 150 mm was placed on it. The static load tests under different states were done in Weihao Central Park in Dongying, Shandong province. The comparable research on the dry powder cement single pile in composite foundation and the free single pile was done. The results show that the capacity of dry powder cement single pile in composite foundation is much higher than that of a free single pile. The new type of construction between the pile top and bearing plate could mobilize the bearing capacity of soil effectively, and reduce the stress concentration at pile top. In the meantime, the soil surrounding the piles was compacted earlier than that of coventional composite foundation under the same load, which would make piles and soil settle together. The post-construction settlement may be reduced.