浅覆盖层条件下大埋深水中承台施工技术研究

发布时间：2018-04-09 08:02

本文选题：高压旋喷　切入点：钢板桩　出处：《湖北工业大学》2017年硕士论文

【摘要】：成都市是四川省的省会城市,天府新区是四川省的首个国家级新区,货运通道工程是天府新区行政区域内的国家级投资工程建设项目,该工程在创新大道末端DK36+860~DK37+238区段新建锦江大桥跨越成都市的泄洪通道即府河又名锦江河,桥区位于火石岩村“U”型河道区段内,该处河道宽度达70m,且主跨3#桥墩处于“U”型河道的河槽较低区域,河床含约1~2m厚的卵石层,该河道区段上层地质覆盖层都非常薄,其下层为强风化泥岩夹砂岩,因此设计上采用桥梁结构跨越。锦江大桥全长378m,结构形式为:30m简支箱梁+(35m+3×60m+35m)支架现浇连续箱梁+3×30m现浇连续箱梁,其中主跨3#墩承台底标高为441.503m,预计施工期间洪水位约为451.0m,基坑开挖深度9.497m,桩基施工前采用粘土填筑平台,该墩在基坑开挖时若按照常规施工方式,将产生严重渗水,存在极大的安全隐患。所以本课题旨在论证采用双排Φ0.5m咬合高压旋喷桩进行止水,同时配合使用拉森Ⅳ型钢板桩对基坑进行支护的施工工艺,能保证开挖施工时基坑不产生渗水,进而保证承台干施工条件。本课题研究内容包括水中施工平台筑岛技术、基坑止水技术、围堰基坑支护技术、深基坑岩层开挖技术和汛期围堰筑岛平台防洪技术。通过本次工程实例论证,采用高压旋喷桩搭配拉森Ⅳ型钢板桩止水对于黏土层止水效果良好,该工艺能有效的防止基坑渗水,保证基坑施工安全,而且采用三重管高压旋喷桩可在桩基施工时同步施工,能够充分节约工期,且在插打钢板桩时不会出现交错影响,对于本工程汛期的快速施工极为有利。通过本课题的研究,促使施工企业在浅覆盖层条件下大埋深水中承台施工技术有所创新和突破,同时在本课题研究成果的基础上,进行扩展形成系统的浅覆盖层条件下大埋深水中承台施工技术,在桥梁工程建设飞速发展的今天,具有广阔的应用前景,对进一步带动基建行业在该技术领域的共同进步和发展有深远意义。
[Abstract]:Chengdu city is the capital city of Sichuan Province, Tianfu new area is the first national district in Sichuan Province, freight corridor project is the national investment construction project administrative area of Tianfu District in the discharge channel of the project in the end section of the new Jinjiang DK36+860~DK37+238 innovation Avenue bridge across the city of Chengdu is also known as Jin Fu River Bridge area is located in the river, the flint rock village "U" river section, the channel width is up to 70m, and the main span of 3# bridge in the "U" type of river channel low, river bed with gravel layer about 1~2m thick, the upper section of river geological layer is very thin, the lower mudstone weathered sandstone, so design of the bridge across the Jinjiang bridge. The full-length 378m structure: 30m simply supported box girder + (35m+3 * 60m+35m) support cast-in-place continuous box girder +3 * 30m Cast-in-situ Continuous Box Girder, the main span of 3# pier bearing platform bottom elevation is 44 1.503m, is expected during the construction of the flood level is about 451.0m, 9.497m depth of excavation, clay filling platform with pile foundation construction, the pier in the excavation according to the conventional construction methods will lead to serious water seepage, there is a big security risk. So the purpose of this study is to demonstrate by double 0.5m occlusion of high pressure jet grouting pile for water sealing at the same time with the use of type IV Larson steel sheet pile for foundation pit supporting construction technology, to ensure the construction of foundation pit excavation without water seepage, and ensure the construction conditions of pile cap dry. This paper includes the technology for island water construction platform, foundation pit waterproof technology, cofferdam excavation technology, deep foundation pit excavation of rock and flood cofferdam island platform of flood control technology. Through the demonstration of this project, using high pressure jet grouting pile collocation Larson steel sheet pile type IV for sealing the sealing effect of clay layer is good, the process can Effectively prevent pit seepage, ensure the safety of foundation pit construction, and adopts three pipe high pressure jet grouting pile construction can be synchronized in the pile foundation construction, can save time, and inserting the steel sheet pile does not appear staggered, for rapid construction of the project in flood season is extremely beneficial. Through the research, promotes the construction enterprises in the shallow layer under the condition of large buried deep in the pile cap construction technology innovation and breakthroughs, based on the research on the construction technology of deep buried large cap shallow overburden conditions were extended to form the system, in the bridge construction rapid development today, has a wide application prospect and profound the significance of the common progress and development and further promote the construction industry in the technical field.

【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U445.559

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