深大沉井基础基底承载力现场试验研究
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摘要
针对至今尚未解决的深层土体承载能力现场试验确定问题,依托沪通长江大桥主墩深大沉井基础的建设,利用自行研发的深厚土层高压防水自稳型荷载测试装置,开展现场载荷试验,获得了沉井底部土层荷载-沉降曲线。试验结果表明:沉井底部土层极限承载力大于6.5 MPa。在此基础上,借助现有理论分析得出相应地基土体的变形模量为12.69 MPa,地基系数为36.79 MN/m~3。与现行《铁路桥涵地基和基础设计规范》相比较,地基承载力现场实测值比以安全系数2推算得到的规范值大15.3%。该测试装置的研发和试验结果的获得,为深基础基底土体承载力的现场测试提供了可靠的测试方法和设备,对于深基础设计计算理论的完善、相关规范的修订和施工工艺的优化等具有重要意义。
In order to solve the problem of determining the bearing capacity of deep soil by field test, a high pressure waterproof self-stabilizing load testing device was used, which was developed by the tester particularly for field load experiment, to test subsoil under deep foundation in the construction of main pier deep open caisson of Hutong Changjiang River Bridge. The soil load-settlement curve of the subsoil under caisson was obtained. It is found that the ultimate bearing capacity of the subsoil under deep foundation is greater than 6.5 MPa, from which it can be derived the deformation modulus of foundation is 12.69 MPa and foundation coefficient is 36.79 MN/m~3. Compared with Design Specification for Foundation and Foundation of Railway Bridge and Culvert, the measured value of bearing capacity is 15.3% more than the standard value which takes safety coefficient of 2. The found and testing device provide a reliable test method and equipment for the field test of bearing capacity of subsoil under deep foundation. It is of great significance to perfect the design and calculation theory, relevant specification and construction process of deep foundation.
In order to solve the problem of determining the bearing capacity of deep soil by field test, a high pressure waterproof self-stabilizing load testing device was used, which was developed by the tester particularly for field load experiment, to test subsoil under deep foundation in the construction of main pier deep open caisson of Hutong Changjiang River Bridge. The soil load-settlement curve of the subsoil under caisson was obtained. It is found that the ultimate bearing capacity of the subsoil under deep foundation is greater than 6.5 MPa, from which it can be derived the deformation modulus of foundation is 12.69 MPa and foundation coefficient is 36.79 MN/m~3. Compared with Design Specification for Foundation and Foundation of Railway Bridge and Culvert, the measured value of bearing capacity is 15.3% more than the standard value which takes safety coefficient of 2. The found and testing device provide a reliable test method and equipment for the field test of bearing capacity of subsoil under deep foundation. It is of great significance to perfect the design and calculation theory, relevant specification and construction process of deep foundation.
引文
[1]高宗余,梅新咏,徐伟,等.沪通长江大桥总体设计[J].桥梁建设,2015,45(6):1-6.GAO Zongyu,MEI Xinyong,XU Wei,et al.Overall design of Hutong Changjiang River bridge[J].Bridge Construction,2015,45(6):1-6.
[2]Thomas S,Ben W,Tim M.Crossing the narrows[J].Civil Engineering,ASCE,2008,78(2):38-47.
[3]Iain M.Three-part story[J].Bridge Design&Engineering,2006,26(2):24-26.
[4]Dae Yong Park,BO Be Lee.Second Dolsan Bridge:Acable-stayed bridge with a concrete edge girder[J].Structural Engineering International,2012,22(1):44-48.
[5]Magnus G,Pedro M B,Jorgen S S,et al.Large scale offshore static pile tests-practicality and benefits[J].Bautechnik,2017,94(12):842-850.
[6]付学问,雷金山,叶志凌,等.益马高速典型地层桩基自平衡试验研究[J].铁道科学与工程学报,2016,13(11):2163-2167.FU Xuewen,LEI Jinshan,YE Zhiling,et al.Studies on a self-balanced test for typical stratigraphic piles of YIMAfreeway[J].Journal of Railway Science and Engineering,2016,13(11):2163-2167.
[7]武丹丹,杨成斌,王江涛.深层平板载荷试验在某工程中的应用[J].建筑结构,2015,45(1):91-93.WU Dandan,YANG Chengbin,WANG Jiangtao.Application of deep plate loading test in a project[J].Building Structure,2015,45(1):91-93.
[8]吴银柱,杨国春,王文臣.深层平板载荷试验测试装置的研制[J].岩土工程学报,2002,24(6):756-759.WU Yinzhu,YANG Guochun,WANG Wenchen.Research on the testing device of deep plate loading test[J].Chinese Journal of Geotechnical Engineering,2002,24(6):756-759.
[9]季永新,肖治宇,李新刚,等.超深地基超大荷载自反力静载试验方法研究[J].施工技术,2015,44(1):78-80.JI Yongxin,XIAO Zhiyu,LI Xingang,et al.Research on self-reaction static loading test for super deep foundation under extremely large loading[J].Construction Technology,2015,44(1):78-80.
[10]TB 10002.5-2005,铁路桥涵地基和基础设计规范[S].TB 10002.5-2005,Code for foundation and foundation design of railway bridges and culverts[S].
[11]GB 50021-2001,岩土工程勘察规范(2009年版)[S].GB 50021-2001,Code for geotechnical investigation(2009 edition)[S].
[2]Thomas S,Ben W,Tim M.Crossing the narrows[J].Civil Engineering,ASCE,2008,78(2):38-47.
[3]Iain M.Three-part story[J].Bridge Design&Engineering,2006,26(2):24-26.
[4]Dae Yong Park,BO Be Lee.Second Dolsan Bridge:Acable-stayed bridge with a concrete edge girder[J].Structural Engineering International,2012,22(1):44-48.
[5]Magnus G,Pedro M B,Jorgen S S,et al.Large scale offshore static pile tests-practicality and benefits[J].Bautechnik,2017,94(12):842-850.
[6]付学问,雷金山,叶志凌,等.益马高速典型地层桩基自平衡试验研究[J].铁道科学与工程学报,2016,13(11):2163-2167.FU Xuewen,LEI Jinshan,YE Zhiling,et al.Studies on a self-balanced test for typical stratigraphic piles of YIMAfreeway[J].Journal of Railway Science and Engineering,2016,13(11):2163-2167.
[7]武丹丹,杨成斌,王江涛.深层平板载荷试验在某工程中的应用[J].建筑结构,2015,45(1):91-93.WU Dandan,YANG Chengbin,WANG Jiangtao.Application of deep plate loading test in a project[J].Building Structure,2015,45(1):91-93.
[8]吴银柱,杨国春,王文臣.深层平板载荷试验测试装置的研制[J].岩土工程学报,2002,24(6):756-759.WU Yinzhu,YANG Guochun,WANG Wenchen.Research on the testing device of deep plate loading test[J].Chinese Journal of Geotechnical Engineering,2002,24(6):756-759.
[9]季永新,肖治宇,李新刚,等.超深地基超大荷载自反力静载试验方法研究[J].施工技术,2015,44(1):78-80.JI Yongxin,XIAO Zhiyu,LI Xingang,et al.Research on self-reaction static loading test for super deep foundation under extremely large loading[J].Construction Technology,2015,44(1):78-80.
[10]TB 10002.5-2005,铁路桥涵地基和基础设计规范[S].TB 10002.5-2005,Code for foundation and foundation design of railway bridges and culverts[S].
[11]GB 50021-2001,岩土工程勘察规范(2009年版)[S].GB 50021-2001,Code for geotechnical investigation(2009 edition)[S].