路堤荷载下钉形搅拌桩复合地基附加应力扩散特性  

Additional Stress Distribution Behavior of T-shaped Deep Mixed Column Composite Foundation Under Embankment Load

作　　者：易耀林[1] 刘松玉[1] 杜延军[1] 

机构地区：[1]东南大学岩土工程研究所,江苏南京210096

出　　处：《中国公路学报》2009年第5期8-14,33,共8页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(50879011);江苏省普通高校研究生科研创新计划项目(CX08B_101Z);东南大学优秀博士学位论文基金项目(YBJJ0914)

摘　　要：用三维有限差分方法建立了钉形搅拌桩复合地基的数值模型,分析了钉形搅拌桩复合地基设计参数对附加应力扩散的影响,并基于钉形搅拌桩复合地基的附加应力分布特性,提出了考虑应力集中效应的下卧层附加应力计算模型。结果表明:复合地基中桩体的存在减缓了附加应力的扩散,与天然地基相比,相同深度复合地基路中心加固区的附加应力较小,而下卧层的附加应力较大;钉形搅拌桩的扩大头高度、扩大头直径、桩长、桩间距、桩身模量是影响路堤荷载下钉形搅拌桩复合地基附加应力分布的主要因素;所提出的下卧层附加应力计算模型具有较好的适用性。Three-dimensional finite difference method was used to establish the numerical model of T-shaped deep mixed column composite foundation. Then, the influence of the design parameters of T-shaped deep mixed column composite foundation on additional stress distribution was analyzed. Based on the additional stress distribution behavior of the foundation, considering stress concentration phenomenon, a calculated model was proposed to calculate additional stress in substratum of composite foundation under embankment load. The results indicate that the column effect slows down the distribution of the additional stress in composite foundation. The additional stress in the middle of road in improved area of composite foundation is lower than that of natural foundation at the same depth, while the additional stress in substratum of composite foundation is larger than that of natural foundation. The enlarged column cap height, enlarged column cap diameter, column length, column spacing and column modulus are the main parameters which effect the additional stress distribution behavior of T-shaped deep mixed column composite foundation under embankment load. The proposed calculated model of additional stress in substratum of composite foundation is more efficiently than conventional model.

关 键 词：道路工程 复合地基 数值模拟 附加应力 钉形搅拌桩 路堤荷载 

分 类 号：U416.1[交通运输工程—道路与铁道工程]