碎石桩复合地基的液化判别方法  

A new method in evaluating liquefaction of gravel pile composite foundation

作　　者：周元强[1] 白闰平[2,3] 邵勤 刘欣良[1] 

机构地区：[1]江苏省电力设计院,江苏南京211102 [2]同济大学地下建筑与工程系,上海200092 [3]南京水利科学研究院,江苏南京210029 [4]江苏省电力公司电力经济研究院,江苏南京210029

出　　处：《水利水运工程学报》2014年第5期87-94,共8页Hydro-Science and Engineering

基　　金：南京水利科学研究院博士论文基金资助项目(No.LB31305)

摘　　要：针对目前适用于碎石桩复合地基液化判别方法相对缺乏的现状,依据碎石桩复合地基中地震剪应力按碎石桩和桩间土刚度不同来分配的思路、以Seed剪应力法和美国NCEER协会推荐的抗液化剪应力比公式为基础,提出适用于碎石桩复合地基的液化判别方法,并采用有限元数值模拟方法模拟了地震中碎石桩复合地基桩间土的剪应力变化。模拟分析结果表明,在打设碎石桩后桩间土的地震剪应力小于打设碎石桩前的地震剪应力,说明刚度较大的碎石桩分担了较大的地震剪应力,而刚度较小的桩间土分担了较小的地震剪应力。最后对比了有限元数值模拟结果、我国规范法判别结果和本文方法的判别结果,得出本文方法可以作为一种碎石桩复合地基的液化判别方法。In view of the scarcity of evaluation formula for liquefaction in the gravel pile composite foundation, this paper presents an evaluation method for the liquefaction in the gravel pile composite foundation, which is based on thinking that the distribution of the seismic shear stress is in accordance with the stiffness of the gravel piles and soil, and Seed＇s method and USA NCEER method. A finite element numerical simulation method has been used to simulate the changs in the seismic shear stress in the condition of the gravel pile composite foundation and soil foundation. Simulation analysis results show that the seismic shear stress of the gravel pile composite foundation is greater than the seismic shear force of the soil foundation, which means that the gravel piles which have greater stiffness distribute greater seismic shear stress, and that soil distributes the smaller seismic shear stress because its stiffness is smaller than the gravel piles. In addition, the comparison among the simulated results given by the finite element method, the evaluated results given by the method of this paper and the evaluated results given by the method of Chinese Code for Seismic Design of Buildings is made in this study, and the comparison results show that the method presented by this paper is reasonable in evaluating the liquefaction in the gravel pile composite foundation.

关 键 词：液化判别方法 碎石桩复合地基 剪应力对比法 标贯试验 有限元数值模拟 

分 类 号：TU472[建筑科学—结构工程]