厚垫层-砂桩复合地基现场试验研究  

Field test on composite foundation with thick cushion and sand pile group

作　　者：王正振[1,2] 龚维明[1,2] 戴国亮[1,2] 王晓阳 李亮亮 肖刚 WANG Zheng-zhen;GONG Wei-ming;DAI Guo-liang;WANG Xiao-yang;LI Liang-liang;XIAO Gang(Key Laboratory of Concrete and Prestressed Concrete Structure of Ministry of Education,Southeast University,Nanjing,Jiangsu 210096,China;School of Civil Engineering,Southeast University,Nanj ing,Jiangsu 210096,China;Zhejiang Provincial Institute of Communication Planning,Design ＆ Research,Zhejiang,Hangzhou 310016,China)

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏南京210096 [2]东南大学土木工程学院,江苏南京210096 [3]浙江省交通规划设计研究院,浙江杭州310006

出　　处：《岩土力学》2018年第10期3755-3762,共8页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划(973计划)(No.2013CB036304);"十二五"交通运输重大科技专项(No.2011318494160)~~

摘　　要：以瓯江北口大桥南锚碇巨型沉井场地地基处理为科研背景,研究厚垫层-砂桩复合地基的适用性及其承载力的影响因素,针对不同的垫层材料、垫层厚度和砂桩间距共进行了9组静载试验。为得到砂桩施工对周围已完成砂桩的影响程度,还进行了砂桩施工相互影响试验。试验结果表明:厚垫层-砂桩加固软土地基效果非常好,是大型沉井地基处理较为理想的方式;垫层含水率、垫层材料和垫层厚度对其承载力的影响程度均大于砂桩间距;砂桩施工过程对周围已完成砂桩的影响和对周围土体的影响具有很大差别,利用传统沉桩挤土理论分析砂桩施工对周围已完成砂桩的影响将产生较大偏差;砂桩施工对周围已完成砂桩会产生较大影响,最大影响范围主要集中在地表以下1/3桩长范围内,影响程度与土层的种类和性质有密切关系,土性越好,影响程度越小;可利用增大砂桩间距和已有砂桩的阻隔效应减小影响程度。Base on the foundation treatment of south anchorage caisson of Wenzhou Oujiang Estuary Bridge, nine groups of field static loading tests on composite foundation with thick cushion and sand pile group of different cushion materials, cushion thicknesses and pile spacings were performed to study the application of this composite foundation and influencing factors of its bearing capacity. The interaction test on sand piles installation was conducted to investigate the impact of sand pile installation on completed sand piles. The results show that thick cushion and sand pile group, which can strengthen the soft foundation very well, is an ideal way of foundation treatment of super-large caissons. Water content of cushion, material of cushion and thickness of cushion have greater influence on bearing capacity than pile spacing. Because of the differences between the impact on sand pile and the impact on soil which are caused by installation of sand pile, it is inaccurate to use compaction effect of static-press pile to analyze the impact on existing sand pile. The impact on existing sand pile is very large and the maximum impact concentrates on the 1/3 pile length below earth surface. At the same time, the better of soil property, the smaller of this impact. A big pile spacing and blocking effect of existing sand pile can effectively reduce the impact.

关 键 词：巨型沉井 复合地基 静载试验 影响因素 水平位移 

分 类 号：TU473.1[建筑科学—结构工程]