柔性荷载作用下桩筏加固地基变形特性试验研究  

Experimental Research on Deformation Characteristics of Piled Raft Foundation under Flexible Load

作　　者：邵国霞[1] 苏谦[1] 陈尚勇[2] 白皓[3] 王武斌[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]中铁第四勘察设计院集团有限公司,湖北武汉430063 [3]四川高速公路建设开发总公司,四川成都610041

出　　处：《西南交通大学学报》2017年第1期30-37,共8页Journal of Southwest Jiaotong University

基　　金：中央高校基本科研业务费专项资金资助项目(2682015CX008EM);国家自然科学基金资助项目(51378441)

摘　　要：针对深厚软土地区桩筏加固地基,通过原位长期观测试验,研究柔性荷载作用下桩筏加固地基与天然地基的地基面总沉降、地基分层沉降和侧向变形、地基土孔隙水压力等,对比分析两种地基变形规律的差异性,总结提出了柔性荷载作用下桩筏加固地基的受力变形机理.研究结果表明:桩筏结构相对于天然地基,其总沉降减小至24%、差异沉降减小至0.9%,说明其整体刚度较大,有利于均化地基荷载、约束地基侧向变形,使地基总沉降和差异沉降都有很大程度降低;桩筏加固地基沉降主要发生于下卧层,占总沉降的90%;路堤荷载大部分由桩筏结构承担,桩筏结构地基中超孔隙水压力相对于天然地基降低了70%,从而减小了地基沉降量.To study the pile-raft foundation in thick soft clay ground, total settlements of foundation surface, layered settlements, lateral deformations, and pore water pressures of foundation soil for pile- raft foundation and natural foundation were observed and analyzed by long-time in-situ test. The load and deformation mechanism of pile-raft foundation under flexible load was proposed by the comparative analysis of the deformation differences between the two types of foundations. The results show that the total settlement of pile-raft foundation is reduced to be the 24% total settlement of the natural foundation, and the differential settlement is reduce to be 0. 9%. This means that the pile-raft foundation has lager integral rigidity, which can homogenize the load and restrict the lateral deformation, and lead to the reduction in the total settlement and differential settlement. The settlement of the pile-raft foundation in substratum is the main part of total settlement, which accounts for the 90% total settlement. The pile-raft structure bears the most subgrade load. Compared with that of the natural foundation, the excess pore water pressure of the pile-raft foundation is reduced by about 70% ; therefore, the settlement of foundation is reduced.

关 键 词：柔性荷载 桩筏加固地基 原位长期试验 变形机理 超孔隙水压力口 

分 类 号：U213.1[交通运输工程—道路与铁道工程]