路堤下钉形搅拌桩复合地基性状的数值分析  

NUMERICAL ANALYSIS OF BEHAVIOR OF T-SHAPED CEMENT-SOIL DEEP MIXING PILE COMPOSITE FOUNDATION UNDER EMBANKMENT LOADS

作　　者：易耀林[1] 刘松玉[1] 

机构地区：[1]东南大学岩土工程研究所,南京210096

出　　处：《工业建筑》2008年第11期63-68,共6页Industrial Construction

基　　金：国家自然科学基金资助项目(50879011);江苏省普通高校研究生科研创新计划资助项目(CX08B-101Z)

摘　　要：针对国内水泥土搅拌桩存在的问题,介绍一种新型水泥土搅拌桩——钉形搅拌桩,在现场试验的基础上通过三维数值模拟对路堤荷载下钉形搅拌桩和常规搅拌桩复合地基的工作性状进行对比分析,结果表明:在其他条件相同的情况下,由于钉形搅拌桩的扩大头作用,钉形搅拌桩的桩体荷载分担比高于常规搅拌桩,而相同深度加固区上部的桩身负摩阻力小于常规搅拌桩;钉形搅拌桩复合地基加固区上部的土体附加应力小于常规搅拌桩复合地基;与常规搅拌桩相比,钉形搅拌桩不仅能有效减小复合地基地表桩、土沉降、坡角侧向位移,更重要的是可以有效减小地表桩土差异沉降,防止发生桩顶向上刺入破坏,不需在顶部设置加筋及垫层。With a review of disadvantages of traditional deep mixing cement-soil pile techniques, a new type of cement-soil deep mixing technique named T-shaped cement-soil deep mixing pile is introduced. Three-dimensional numerical simulation is taken to analyze the behavior of T-shaped cement-soil deep mixing pile composite foundation under embankment loads comparing with ordinary shaped cement-soil deep mixing pile based on filed tests. The results indicate that when other parameters keep the same, because of the effect of enlarged cap of T-shaped cement-soil deep mixing pile, load sharing ratio of T-shaped cement-soil deep mixing pile is higher than ordinary shaped cement-soil deep mixing pile, but the negative skin friction of T-shaped pile is less than of ordinary pile in the upper reinforced area; additional stress in the upper T-shaped cement-soil deep mixing pile composite foundation is less than that of ordinary cement-soil deep mixing pile composite foundation; comparing to ordinary cement-soil deep mixing pile composite foundation, T-shaped cement-soil deep mixing pile can not only decrease the surface settlement of composite foundation and the lateral displacement in embankment foot, but also can decrease the differential settlement of composite foundation surface efficiently, so there is no need for cushion or geosynthetie-reinforced layer set above the pile top.

关 键 词：钉形搅拌桩 数值模拟 荷载传递 地表沉降 差异沉降 

分 类 号：TU473.1[建筑科学—结构工程]