沉管基础岛–隧过渡段地基处理设计及试验验证  

Foundation treatment design and experimental study for immersed tube tunnel at the island-tunnel joint part

作　　者：王延宁[1,2,3] 蒋斌松 张强[1] 李建宇[4] 陈运涛[3] WANG Yanning;JIANG Binsong;ZHANG Qiang;LI Jianyu;CHEN Yuntao(State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology, Xuzhou,Jiangsu 221000,China;Department of Civil Engineering,Shantou University,Shantou,Guangdong 515063,China;Tianjin Port Engineering Institute,China Communications Construction Company Limited(CCCC),Tianjin 300222,China;CCCC-FHDI Engineering Co.,Ltd.,Guangzhou,Guangdong 510230,China)

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221000 [2]汕头大学土木工程系,广东汕头515063 [3]中交天津港湾工程研究院,天津300222 [4]中交第四航务工程勘察设计院有限公司,广东广州510230

出　　处：《岩石力学与工程学报》2018年第A02期4297-4307,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家科技支撑计划课题(2011BAG07B03);国家自然科学基金资助项目(51109209,51204168)~~

摘　　要：港珠澳大桥岛-隧过渡段沉管基础下部存在深厚软土,为实现岛-隧转换部位基础刚度的平滑过渡,经比选设计采用挤密砂桩地基处理方式,通过控制面积置换率来实现这一目标。给出设计依据及具体的设计参数并通过原位堆载试验进行验证,通过水下安装液体压差式沉降仪实测加载过程中的地基沉降,获得较好试验数据。采用指数三点法、双曲线法及Asaoka法预测地基最终沉降并与设计计算结果比对。试验表明:通过原位堆载验证设计计算的方法直接有效,可作为重要工程地基分析的辅助手段;3种预测方法得到的结果差距不大,双曲线法得到的预测值略大;使用三点法应尽可能选取较大时间间隔来获得理想结果;对于高置换率挤密砂桩,使用日本经验公式计算结果与实测值相比明显偏大,而采用与低置换率相同的经验公式得到的结果与实测值较接近。本文研究结果期望对于水下挤密砂桩复合地基的设计计算和现场原位测试提供一定的参考。There is a deep soft soil under the immersed tube foundation of the Hong Kong-Zhuhai-Macao Bridge(HZMB) island-tunnel joint part. In order to make the foundation stiffness smooth transition at the position,the sand compaction pile(SCP) method was adopted for its no pollution and speedy construction compared with some other treatment methods such as offshore cement deep mixing(CDM) or gravel compaction pile(GCP). This goal will be achieved by controlling the SCP area replacement rate. In this paper,the design basis and the specific design parameters are given and verified by the in situ loading test. Better settlement data was obtained by the application of liquid pressure settlement sensor at the loading process. The three-point method,the hyperbol-ic method and the Asaoka method are employed to predict the ultimate settlement of the foundation. The result predicted by the three method were discussed with the calculation results proposed by Aboshi. It was showed that the in-situ load verification method is directly effective. It can be used as an auxiliary method for the analysis of important engineering foundations. The results obtained by these prediction methods are basic equivalent whereas the results obtained by the hyperbolic method are slightly larger than the other two method. It should be selected a larger time in-thermal as much as possible to get the preferable results when the three-point method was adopted. For the high displacement rate compacted sand piles,the results calculated by the empirical formula proposed by Aboshi are significantly larger than the test results whereas they are very closed to the results calculated by the same formula with the low area replace ratio. The study is expected to provide some reference meaning for the SCP design and in situ test techniques.

关 键 词：隧道工程 沉管隧道 挤密砂桩设计 沉降计算 原位测试 

分 类 号：U45[建筑科学—桥梁与隧道工程]