加筋褥垫层在PCC桩复合地基中的影响研究  

Influence of reinforced cushion in PCC pile composite foundation

作　　者：刘汉龙[1] 谭慧明[2] 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]河海大学岩土工程科学研究所,江苏南京210098

出　　处：《岩土工程学报》2008年第9期1270-1275,共6页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(50679017);江苏省"六大人才高峰"基金项目(50528512)

摘　　要：通过现场试验,测得了路堤下PCC桩复合地基桩土差异沉降及应力比随路堤填筑的变化过程线。试验表明,加筋褥垫层性质对桩土差异沉降以及应力比会产生影响;加筋材料不同的预张拉程度会产生前期增长型和后期增长型两种桩土应力比增长模式,提高预张拉程度对减小地基水平位移是有利的。此外,采用数值模拟方法对褥垫层中加筋材料抗拉强度及铺设层数和位置的影响研究表明,提高加筋材料的抗拉强度,对减小桩土差异沉降、提高桩土应力比是有利的;改变加筋材料铺设层数和位置也会产生一定的影响,但影响程度较小。Based on the in-situ tests, the development of differential settlement and stress ratio between PCC piles and soil was obtained. The material and thickness of reinforced cushion had an effect on the differential settlement and stress ratio. Therefore, the deformability of cushion and the reinforcing effect of geogrid in cushion should be taken into account. Different laying technology of cushion, such as pre-tension of geogrid, would result in different growing modes of pile-soil stress ratio. The larger the tensile force of geogrid was in laying, the faster the pile-soil stress ratio would develop. Furthermore, the numerical analyses by use of the finite element method were also made to study the influence of the tensile strength and arrangement of geogrid on the pile-soil differential settlement and stress ratio. It was indicated that with the increase of tensile strength of geogrid, the more loads would be supported by piles, which led to increase the bearing capacity of the composite foundation, and the pile-soil differential settlement would be reduced. However, the influence of number of layers and laying place of geogrid, especially the laying place, is almost negligible.

关 键 词：加筋褥垫层 PCC桩 差异沉降 应力比 复合地基 

分 类 号：TU473.1[建筑科学—结构工程]