软土地区人行地道桩基础类型选择探讨

Research on Selection of Pile Foundation of Pedestrian Subway in Soft Soil Area

人行地道设计通常采用预应力管桩和钻孔灌注桩两种桩基础类型,而软土地区土层承载力弱且压缩性大。针对此类桩基础设计中常遇到的桩长过长、沉降难以控制等问题,本文以珠海西部中心城区市政基础设计工程某在建人行地道为例,对照规范公式进行定量研究,并采用MIDAS GTS建立空间有限元实体模型,细致分析桩径、桩长、桩基承载力、沉降量之间的关系。结果表明:(1)承载力富余量为5%~15%时结构沉降稳定可作为桩长设计依据;(2)在承载力富余量一致的情况下,管桩长度最短,造价优势明显且节段沉降量最低。

To solve problems of poor bearing capacity and high compressibility,prestressed pipe piles and bored piles have been widely applied in soft soil areas.In order to overcome difficulties on overlong pile and inevitable settlement in the design of pile foundation and acquire a comprehensive understanding of the relationship among pile diameter and length,bearing capacity and settlement,a spatial finite element solid model was established by using Midas GTS to conduct quantitative study against the standeird formula based on the project of a constructing pedestrian subway in western central parts of Zhuhai.The results are as follows:(1)stable settlement can be reached with its bearing capacity increasing 5%~15%,this condition could be applied as a basis for pile length design.(2)With the same bearing capacity,the prestressed pipe piles have the shortest length and lowest settlement and lower price.