SDDC工法处理湿陷性黄土地基试验研究  

Experimental Study on Collapsible Loess Foundation Treated by SDDC Method

作　　者：周小松 乔建伟 夏玉云 朱才辉[3] 宋少波 ZHOU Xiaosong;QIAO Jianwei;XIA Yuyun;ZHU Caihui;SONG Shaobo(China JIKAN Research Institute of Engineering Investigation and Design Co.,Ltd.,Xi’an,Shaanxi 710043,China;Shaanxi Laboratory for the Property and Treatment of Special Soil and Rock,Xi’an,Shaanxi 710043,China;Institute of Geotechnical Engineering,Xi’an University of Technology,Xi’an,Shaanxi 710048,China)

机构地区：[1]机械工业勘察设计研究院有限公司,陕西西安710043 [2]陕西省特殊岩土性质与处理重点实验室,陕西西安710043 [3]西安理工大学岩土工程研究所,陕西西安710048

出　　处：《施工技术（中英文）》2023年第21期137-143,共7页Construction Technology

基　　金：陕西省创新能力支撑计划(2022KJXX-05,2023-CX-TD-34,2023-CX-PT-46);国机集团青年科技基金(2022-ZD-01,2022-PY-01);西安市英才计划青年项目(2022XAYC-03);机勘院科技研发基金(11741401120200041)。

摘　　要：研究孔内深层超强夯法(SDDC工法)地基处理效果对处理湿陷性黄土地基具有重要工程实际意义。以西安市白鹿原某在建项目为工程背景,通过原位试验、室内试验和理论计算,研究SDDC的单桩挤密效应,分析不同桩间距下SDDC的挤密效应和承载特性。结果表明:SDDC夯扩桩桩体中部挤密系数大于桩端,其消除桩周黄土湿陷性的水平距离是桩端的3~4倍。SDDC夯扩桩横向挤密系数随距桩心水平距离变化曲线可分为3段,数学关系可用logistic模型进行最优函数拟合。SDDC夯扩桩三角形布桩时,两桩中心挤密系数小于三桩形心,该结果与DDC桩不同,按现有公式设计桩间距偏保守。SDDC桩体、桩间土及其组成的复合地基承载力和变形模量均随桩间距增加而减小,桩间距相同时复合地基承载力提高系数远小于变形模量提高系数。The research on the foundation treatment effect of super down⁃hole dynamic consolidation method(SDDC method)is of great engineering practical significance for the treatment of collapsible loess foundation.Taking a project under construction in Bailuyuan,Xi’an as the engineering background,the in⁃situ test,indoor test and theoretical calculation are used to study the compaction effect of SDDC single pile,and analyze the compaction effect and bearing characteristics of SDDC under different pile spaces.The results show that the compaction coefficient in the middle of SDDC tamping pile is greater than that at the pile end,and the horizontal distance to eliminate the collapsibility of loess around the pile is 3~4 times that at the pile end.The variation curve of the lateral compaction coefficient of SDDC rammed expanded pile with the horizontal distance from the pile center can be divided into three sections,and the mathematical relationship can be fitted with the optimal function by logistic model.When the SDDC rammed expanded pile is arranged in triangle,the compaction coefficient of the center of two piles is less than the centroid of three piles,which is different from DDC.The pile space according to the calculation formula proposed in the existing specifications is conservative.The bearing capacity and deformation modulus of SDDC pile,soil between piles and their composite foundation decrease with the increase of pile space.At the same pile space,the improvement coefficient of bearing capacity of composite foundation is much less than that of deformation modulus.

关 键 词：复合地基 湿陷性黄土 强夯 挤密系数 承载特性 

分 类 号：TU472[建筑科学—结构工程]