SMW工法桩土共同作用模型试验研究及数值模拟分析
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摘要
随着城市地下空间的发展,大量深基坑不断涌现。SMW工法作为一种新型的基坑支护结构,由于其特殊的优点而被广泛应用,但是SMW工法支护形式的桩土共同作用机理仍不明确,因此对SMW工法进行研究具有重要的现实意义。
文章针对SMW工法支护形式,采用了模型试验研究以及三维有限元数值模拟分析,对其桩土共同作用进行了研究,主要成果如下:
1、对试验模型在不同开挖工况下桩顶位移、桩侧土压力以及桩身应力进行了测试。位移测试表明:支护结构变形过程可以分为初始阶段、稳定阶段、位移剧增阶段及破坏四个阶段;联系其嵌固深度得出了该悬臂支护合理的嵌固比λ=0.66;同时位移数据与时间的关系,说明软土基坑支护结构的变形时间效应显著。
2、运用能量法对水泥土横向作用进行研究,研究表明水泥土墙高与基坑边长的比值对该作用影响巨大,且进一步得出了考虑水泥土横向联系的桩顶最大位移值的解析解。
3、从土压力沿深度的分布、随开挖工况的变化、与朗肯极限土压力的比较以及极限土压力与位移关系四个方面来讨论土压力测试结果。得出了试验墙背土压力在深度上为梯形分布;被动土压力小于朗肯被动土压力,计算时建议取其1/3-2/3;主动土压力比朗肯主动土压力稍大;同时得出了本试验的主动极限土压力的所需桩顶位移值及位移速率。
4、桩身应力应变实测值与不考虑水泥土作用的桩身应变计算值对比,从而得出水泥土对桩身刚度的贡献,建议在SMW工法支护结构设计时可以适当的考虑水泥土贡献。
5、运用MIDAS/GTS对试验的进行数值计算,将计算结果与试验实测结果进行对比分析。
With the development of urban construction, lots of deep foundation pits have come forth continuously. As a new support structure for foundation pit, SMW engineering method is widely used due to its especial advantages, but the mechanism of pile-soil interaction of SMW engineering method is still unclear, so it is of great practical significance to study SMW method.
According to the support of SMW engineering method, the mechanism of its pile-soil interaction is studied by model test study and three-dimensional FEM in this paper. The specific contents include the following works:
1. The displacement of piles top, the lateral earth pressure and pile stress of the test model are tested under different excavation situation. The results of displacement mesurement show that the deformation process of support structure can be devided into four phases, that is, original phase, stabilization phase, displacement leap phase and breakage phase. By combining with its mbeded depth, the reasonable embed ratio of the cantilever retaining can be obtained, and its value is 0.66. In addition, the relationship between displacement and time shows that the deformation of the support structure for soft soil foundation pit is significant.
2. The transverse action of cement soil is studied by energy method. The results show that the ratio of the height of cement-soil wall to the side length of foundation pit has significant influence on the effect, and the analytical solution of the maximum displacement value of pile top in view of lateral Contact relation is obtained.
3.The test results are discussed in terms of the distributing of earth pressure, the variety with excavation situation, comparing with Rankine limit earth pressure, along with the relationship between earth limited pressure and displacement. The results show that the distribution of earth pressure in depth for the test wall is trapezoidal. The factual passive earth pressure is less than the Rankine passive earth pressure, the suggested value is 1/3 to 2/3 of its value, while the active earth pressure is a little more than Rankine active earth pressure. Also the needed value of the displacement and its rate of pit top for active limited earth pressure for the model test are obtained.
4. Comparing the measured stress and strain of pile to the calculated values without regard to the work of cement soil, the contribution of cement soil to the rigidity of pile body can be seen, is important, its contribution can be considered in appropriate extent. A suggestion is that of a appropriate contribution of cement soil can be considered in the designing of support structure by SMW engineering method.
5. The test is numerically calculated by MIDAS/GTS. In addition, the comparison of calculated results and measuring results are conducted.
文章针对SMW工法支护形式,采用了模型试验研究以及三维有限元数值模拟分析,对其桩土共同作用进行了研究,主要成果如下:
1、对试验模型在不同开挖工况下桩顶位移、桩侧土压力以及桩身应力进行了测试。位移测试表明:支护结构变形过程可以分为初始阶段、稳定阶段、位移剧增阶段及破坏四个阶段;联系其嵌固深度得出了该悬臂支护合理的嵌固比λ=0.66;同时位移数据与时间的关系,说明软土基坑支护结构的变形时间效应显著。
2、运用能量法对水泥土横向作用进行研究,研究表明水泥土墙高与基坑边长的比值对该作用影响巨大,且进一步得出了考虑水泥土横向联系的桩顶最大位移值的解析解。
3、从土压力沿深度的分布、随开挖工况的变化、与朗肯极限土压力的比较以及极限土压力与位移关系四个方面来讨论土压力测试结果。得出了试验墙背土压力在深度上为梯形分布;被动土压力小于朗肯被动土压力,计算时建议取其1/3-2/3;主动土压力比朗肯主动土压力稍大;同时得出了本试验的主动极限土压力的所需桩顶位移值及位移速率。
4、桩身应力应变实测值与不考虑水泥土作用的桩身应变计算值对比,从而得出水泥土对桩身刚度的贡献,建议在SMW工法支护结构设计时可以适当的考虑水泥土贡献。
5、运用MIDAS/GTS对试验的进行数值计算,将计算结果与试验实测结果进行对比分析。
With the development of urban construction, lots of deep foundation pits have come forth continuously. As a new support structure for foundation pit, SMW engineering method is widely used due to its especial advantages, but the mechanism of pile-soil interaction of SMW engineering method is still unclear, so it is of great practical significance to study SMW method.
According to the support of SMW engineering method, the mechanism of its pile-soil interaction is studied by model test study and three-dimensional FEM in this paper. The specific contents include the following works:
1. The displacement of piles top, the lateral earth pressure and pile stress of the test model are tested under different excavation situation. The results of displacement mesurement show that the deformation process of support structure can be devided into four phases, that is, original phase, stabilization phase, displacement leap phase and breakage phase. By combining with its mbeded depth, the reasonable embed ratio of the cantilever retaining can be obtained, and its value is 0.66. In addition, the relationship between displacement and time shows that the deformation of the support structure for soft soil foundation pit is significant.
2. The transverse action of cement soil is studied by energy method. The results show that the ratio of the height of cement-soil wall to the side length of foundation pit has significant influence on the effect, and the analytical solution of the maximum displacement value of pile top in view of lateral Contact relation is obtained.
3.The test results are discussed in terms of the distributing of earth pressure, the variety with excavation situation, comparing with Rankine limit earth pressure, along with the relationship between earth limited pressure and displacement. The results show that the distribution of earth pressure in depth for the test wall is trapezoidal. The factual passive earth pressure is less than the Rankine passive earth pressure, the suggested value is 1/3 to 2/3 of its value, while the active earth pressure is a little more than Rankine active earth pressure. Also the needed value of the displacement and its rate of pit top for active limited earth pressure for the model test are obtained.
4. Comparing the measured stress and strain of pile to the calculated values without regard to the work of cement soil, the contribution of cement soil to the rigidity of pile body can be seen, is important, its contribution can be considered in appropriate extent. A suggestion is that of a appropriate contribution of cement soil can be considered in the designing of support structure by SMW engineering method.
5. The test is numerically calculated by MIDAS/GTS. In addition, the comparison of calculated results and measuring results are conducted.
引文
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[3]刘霞. SMW工法的设计理论与计算方法[D].南京:南京工业大学, 2004.
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[7]陈辉. SMW工法中型钢-水泥土共同作用的研究[D].天津:天津城市建设学院, 2003.
[8]谢秀栋,方建瑞,李志高.基于遗传算法的SMW围护结构水泥土刚度系数计算[J].岩土工程学报, 2006,11(28): 1422-1444.
[9]周美燕. SMW工法的性能分析及支撑优化设计[D].北京:中国石油大学,2008.
[10]曹宝飞.水泥土变形模量及弹性模量试验研究[J].中国西部科技, 2006,34: 18-19.
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[13]李俊,张小平.某基坑位移、沉降和内力实测结果及预警值讨论[J].岩土力学, 2008,4(29): 1045-1053.
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[17]张冠军,徐永福,博德明. SMW工法型钢起拔试验研究及应用[J].岩石力学与工程学报, 2002 21(3): 444-448.
[18]吴大庆. SMW工法围护结构设计计算方法及应用研究[硕士论文D].西安:西安科技大学, 2006.
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[23]姚燕明,周顺华,刘建国.微型桩基挡土墙稳定性离心模型试验[C].中国土木工程学会第九届土力学及岩土工程学术会议论文集, 2003,10: 609-612.
[24]孙铁成,张明聚,杨茜.深基坑复合土钉支护模型试验研究[J].岩石力学与工程学报,2004,23(25): 2585-2592.
[25]汪班桥,门玉明,陈文玲.土钉墙模型试验研究[J].西安工程学院报, 2002,24(3): 15-17.
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[28]俞晓.深基坑开挖与支护的模型试验与ANSYS分析[博士论文D].武汉:武汉理工大学, 2005.
[29]肖毅,邹勇,俞季民.钉锚结合支护的模型试验研究[J].武汉水利电力大学学报, 1999,32(1) : 1998-1999.
[30]张彬.深基坑水土压力共同作用试验研究与机理分析[博士论文D].武汉:武汉大学, 2004.
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[35]郭文爱,钱德玲.悬臂排桩支护结构桩顶最大水平位移计算分析[J].合肥工业大学学报, 2007,6(30): 753-757.
[36]杨林德,仇圣华,杨志锡.基坑围护位移量及其稳定性预测[J].岩土力学, 2001,3(22): 267-271.
[37]许锡昌,陈善雄,徐海滨.悬臂排桩支护结构空间变形分析[J].岩土力学, 2006,2(27): 184-189.
[38]何建明,白世伟.深基坑排桩—压顶梁支护结构协同作用研究[J].岩土力学, 1997, 18(3): 41-46.
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[2]陈卫林. SMW工法中型钢-水泥土组合体系的模拟与分析[D].天津:天津城市建设学院, 2007.
[3]刘霞. SMW工法的设计理论与计算方法[D].南京:南京工业大学, 2004.
[4]铃木健夫.柱列ソィルヤメニト连续壁[J].基础工, 1986,(8): 10-15.
[5]铃木健夫,国藤祚光.ソィルヤメニト地中连壁墙の材料特性に关する基础实验[J].土と基础, 1994,42(3): 19-24
[6]王健. H型钢-水泥土组合结构试验研究及SMW工法的设计理论与计算方法:[博士学位论文D],上海:同济大学, 1998.
[7]陈辉. SMW工法中型钢-水泥土共同作用的研究[D].天津:天津城市建设学院, 2003.
[8]谢秀栋,方建瑞,李志高.基于遗传算法的SMW围护结构水泥土刚度系数计算[J].岩土工程学报, 2006,11(28): 1422-1444.
[9]周美燕. SMW工法的性能分析及支撑优化设计[D].北京:中国石油大学,2008.
[10]曹宝飞.水泥土变形模量及弹性模量试验研究[J].中国西部科技, 2006,34: 18-19.
[11]陆新征,宋二祥,吉林,等.某特深基坑考虑支护结构与土体共同作用的三维有限元分析[J].土木工程学报, 2003,25(4): 488-491.
[12]熊智彪.建筑基坑支护[M].北京:中国建筑工业出版社, 2007.
[13]李俊,张小平.某基坑位移、沉降和内力实测结果及预警值讨论[J].岩土力学, 2008,4(29): 1045-1053.
[14]刘建航,侯学渊.基坑工程手册[M].北京:中国建筑工业出版社, 1997.
[15]伊藤康郎.ソィルヤメニト柱列壁の设计上の注意点[J].基础工, 1994,5:8-13.
[16]日比野信一,坞田文夫,内田一善,木村英树.夕了井七声夕卜柱列壁[J].基础工, 1994,(5): 42-48.
[17]张冠军,徐永福,博德明. SMW工法型钢起拔试验研究及应用[J].岩石力学与工程学报, 2002 21(3): 444-448.
[18]吴大庆. SMW工法围护结构设计计算方法及应用研究[硕士论文D].西安:西安科技大学, 2006.
[19]徐少曼,李树华,陈孝贤.软土深基坑开挖的模型试验研究[J].福建建筑,2000, 70: 63-65.
[20] George M. Filz Miehael J. Duneun Robert M. Ebeling Vertieal Shear D Ladon Nomnoving walls11:Aplieation[J]. Journal of Geotechnical and Geoenviorn- mental Engineering,1997,Vol.123,Nog,863-873.
[21] Bolton, M. D. Steedman, R. S. Behaviour of Fixed Cantilever Walls Subject toL–ateralShaking[J]. Conference: Proceedings of a Symposium on the Application of CentrifugeModelling to GeotechnicalDesign.Manchester,Eng1.1985,301-313.
[22]陆培毅,严驰,等.粘性土基于室内模型试验土压力分布形式的研究[J].建筑结构学报,2002,23(2):83-86.
[23]姚燕明,周顺华,刘建国.微型桩基挡土墙稳定性离心模型试验[C].中国土木工程学会第九届土力学及岩土工程学术会议论文集, 2003,10: 609-612.
[24]孙铁成,张明聚,杨茜.深基坑复合土钉支护模型试验研究[J].岩石力学与工程学报,2004,23(25): 2585-2592.
[25]汪班桥,门玉明,陈文玲.土钉墙模型试验研究[J].西安工程学院报, 2002,24(3): 15-17.
[26]顾士坦,施建勇.深基坑SMW工法模拟试验研究及工作机理分析[J].岩土力学, 2008,29(4): 1121-1126
[27]林鹏.基于板桩墙支护的基坑开挖模型试验的三维数值分析及变形预测[D].江西:华东交通大学, 2008.
[28]俞晓.深基坑开挖与支护的模型试验与ANSYS分析[博士论文D].武汉:武汉理工大学, 2005.
[29]肖毅,邹勇,俞季民.钉锚结合支护的模型试验研究[J].武汉水利电力大学学报, 1999,32(1) : 1998-1999.
[30]张彬.深基坑水土压力共同作用试验研究与机理分析[博士论文D].武汉:武汉大学, 2004.
[31]谢宁,孙钧.土体非线性流变的有限元解析及其工程应用[J].岩土工程学报, 1995,4(17): 95-100.
[32]王启云.桩锚体系弹性支点法和三维有限元法比较与分析[J].岩土工程界2008,11(3): 29-32.
[33]左东启.模型试验的理论和方法[M].北京:水利电力出版社, 1984.
[34]张钦,孙家乐,刘柯.深基坑锚拉支护体系变形控制设计理论与应用[J]. 1999,2(21): 161-165.
[35]郭文爱,钱德玲.悬臂排桩支护结构桩顶最大水平位移计算分析[J].合肥工业大学学报, 2007,6(30): 753-757.
[36]杨林德,仇圣华,杨志锡.基坑围护位移量及其稳定性预测[J].岩土力学, 2001,3(22): 267-271.
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