超载软土地基主动加固控制邻近桩基侧向变形分析  

Effect of active ground treatment on pile deflection due to adjacent surcharge loads

作　　者：杨敏[1] 朱碧堂[1] 

机构地区：[1]同济大学地下建筑与工程系,上海200092

出　　处：《建筑结构学报》2003年第4期76-84,共9页Journal of Building Structures

基　　金：上海市科委重点基础研究资助项目(02DJ14062);高等学校博士学科点专项科研基金。

摘　　要：本文以上海某工业厂房为例采用有限元方法讨论了深层搅拌法加固宽度、加固深度等对邻近堆载桩基侧向变位的影响,结果表明:(1)加固存在特征加固深度(临界加固深度和极限加固深度),当加固深度位于临界加固深度和极限加固深度范围内时,可显著降低桩基的侧向变形。当加固深度小于临界加固深度时,不但不能降低邻近桩基的变形,反而会增大桩侧土压力和侧向变形;当加固深度大于极限加固深度后,再增加加固深度效果不明显。加固宽度也有类似现象。(2)加固搅拌桩对邻近堆载桩基侧向位移有三种作用模式,即短桩挤压模式、中长桩遮拦模式和长桩嵌固模式,分别与特征加固深度相对应。(3)在其它条件相同的情况下,提高加固深度比增大加固宽度,能更有效地控制受邻近堆载作用桩基的侧向变形。Finite element analysis was employed to evaluate the effects of the width and depth of soil treated by cement soil deep mixing method in the active zone on the horizontal deflection of piles due to adjacent surcharge loads. The following results have been obtained: (a)There are critical depth/width and ultimate depth/width of cement soil treated block for controlling pile deflection. When the treated soil depth lies between the critical depth and ultimate depth, the lateral deflection of the adjacent piles will be obviously deduced, while the treated depth is less than the critical depth, the lateral pressure on the piles and their deflection will be increased rather than be decreased. If the treated depth is larger than ultimate depth, the effect of increasing depth on decreasing lateral deflection of piles is no longer obvious. The treated width has the similar phenomena on pile deflection as that of the treated depth. (b) There are three modes of lateral deflection of piles affected by surcharge loads and cement soil columns, namely the extrusion of short pile, the sheltering of middle pile and the embedding of long pile.(c) The effect of increase in cement soil depth is more prominent than that of increase in cement soil width on the reduction of pile deflection in this kind of ground treatment.

关 键 词：上海 工业厂房 有限元法 软土地基 桩基 侧向变形 

分 类 号：TU473.1[建筑科学—结构工程]