变荷载作用下碎石桩复合地基固结简化分析  

Simplified analysis for consolidation of stone columns reinforced foundation under general time-dependent loading

作　　者：王双 王睿 杨彪 陈征宙[2] 

机构地区：[1]中国民航机场建设集团公司西南分公司,四川成都610212 [2]南京大学地球科学与工程学院,江苏南京210093

出　　处：《岩土力学》2015年第1期34-40,共7页Rock and Soil Mechanics

基　　金：中国民航机场建设集团公司科技及基础研发项目;国家自然科学基金项目(No.41272313)

摘　　要：用碎石桩对软弱土进行地基处理是一种常用的地基处理方法,桩间土的固结问题是碎石桩复合地基中非常关注的问题,该问题在不同假设条件下的研究也取得了大量成果。在考虑桩土模量比(即应力状态稳定时的桩土应力比)及碎石桩面积置换率影响的前提下,基于等应变假设,将任意变荷载转化为傅里叶级数,从而推导出了变荷载作用下碎石桩桩间土固结解析解,给出了任意时刻桩土承担的应力变化关系,对现有理论进行了合理的修正。通过算例与现有理论对比分析表明,本算法合理可行,当碎石桩面积置换率及桩土模量比比较大时应该考虑其对固结的影响。此外,根据上述理论对Carrillo假设进行了分析,证明竖向和径向固结分别独立考虑的假设并不精确,但得出的总体规律与实际较为接近。Stone column is one of the most commonly used techniques for soft soil improvement in practical engineering projects. The consolidation of the soil between piles is one of the most concerned problems. Studies on the problem under different conditions have been made great progresses. In this paper, the effects of column-soil modular ratio（equivalent to steady state stone column-soil stress concentration ratio） and area replacement ratio of stone column are considered. An equal strain assumption is assumed. As well as a general time-dependent loading is transformed into Fourier series to deduce the analytical solution of consolidation. The stress applied to column and soil at any time is gained respectively. The model gives reasonable modifications to existing theories. Comparisons with other methods demonstrate that the proposed solution is reasonable and accurate. The influence of area replacement ratio and column-soil modular ratio on the soil consolidation should be considered when their values are fairly large. Furthermore, this paper also analyzes the Carrillo hypothesis that vertical and radial consolidation can be considered independently. The result shows that the hypothesis is not accurate although the general trend holds true.

关 键 词：碎石桩复合地基 桩土应力比 变荷载 固结 傅里叶级数 

分 类 号：TU473[建筑科学—结构工程]