摘要
Based on the variational approach for pile groups embedded in soil modeled using a load-transfer curve method, a practical method was conducted to estimate the settlement of symmetric pile group supported embankments. The working mechanism of composite foundations improved by rigid or semi-rigid columns is analyzed by this method. Under equivalent strain conditions, the pile-soil stress ratio approaches the pile-soil modulus ratio up to a limited value of pile stiffness （Rm〈10）; in the subsequent stages of high pile stiffness （Rm〉10）, a further increase in the pile-soil modulus ratio cannot lead to a significant increase of stress transferred to the columns in composite foundations. The major influencing factor of the stress concentration from soil to pile in a high pile-soil modulus ratio is the padding stiffness. For the composite foundation improved by cement mixing columns, the effective column length is about 15 to 20 m and it is a more economical and effective design when the column length is less than 15 m.
基于土中群桩分析变分原理,结合桩间土荷载传递法,建立了实用群桩沉降计算方法,并应用于对称桩承路堤结构分析.采用该计算方法,分析了刚性、半刚性竖向加固体复合地基的工作机理.在等应变条件下,桩土模量比相对较低时(Rm<10),桩土应力比与桩土模量比相近;在桩土模量比较高时(Rm>10),桩身模量提高对复合地基应力集中的影响减弱.垫层刚度直接影响桩土模量增加对应力集中的作用效果.水泥搅拌桩有效桩长为15～20m,采用小于15m桩长的经济效益和加固效率更加.
基金
TheTransportationScientificFoundationofJiangsuProvince(No.02Y015).
