路堤荷载下柔性桩复合地基沉降实用计算方法  

Practical method for settlement calculation of flexible columns composite foundation under embankment

作　　者：章定文[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：《岩土力学》2007年第6期1133-1138,共6页Rock and Soil Mechanics

基　　金：教育部博士点基金资助项目(No.2001028618);东南大学优秀博士学位论文基金项目(No.YBJJ0603)

摘　　要：根据等应变假设得到的复合地基加固区复合模量计算公式与实际路堤荷载下柔性桩桩土间的非等应变事实不符,因此,路堤荷载下复合模量法计算的沉降量多小于实测值。通过二维有限元方法分析了路堤荷载下复合地基变形特性。采用分层总和法反算加固区复合模量,提出了复合模量计算修正方法;并通过参数分析得到了各主要影响因素对复合地基加固区变形特性的影响;对比桩体设置前后下卧层变形差异,对下卧层沉降计算方法进行修正。由此建立了有限元方法与工程实用的分层总和法之间的联系,将有限元方法实用化,分别得到了路堤荷载下柔性桩复合地基加固区和下卧层的沉降实用计算方法。实例计算证明了所推荐方法的有效性。The traditional calculating method of composite modulus is based on the assumption of the displacement compatibility between the flexible columns and the surrounding soil. However, case histories of embankment on ground improved by flexible columns revealed that the magnitude of the settlement of surrounding soil is often larger than that of flexible columns. The traditional composite modulus method may under-estimate the settlement of composite foundation under embankment. A two dimension finite element method （FEM） is adopted to capture the displacement incompatibility between the flexible columns and the surrounding soil under embankment and to investigate the factors influencing the settlement of composite foundation. The composite modulus of reinforced zone is back-analyzed by the layer-wise summation method. Comparison of the deformation of substratum before and after flexible columns installation yields the modified calculating method for settlement of substratum. Hence, the FEM is related with the layer-wise summation method. A practical calculating method of settlement of reinforced zone and substratum is put forward, respectively. A case study is also presented for verifying the validity of the proposed method.

关 键 词：柔性桩 复合地基 复合模量 路堤 沉降 有限元方法 

分 类 号：TU472.3[建筑科学—结构工程]