深基坑框架预应力锚杆微型钢管桩联合支护结构力学特性分析
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摘要
针对深基坑工程在施工场地狭窄和存在回填未固结土及土质松散地区施工时遇到的难题,提出框架预应力锚杆微型钢管桩联合支护结构,对其结构构成和工作机制进行详细探讨。基于温克尔弹性地基梁理论,建立锚杆张拉阶段和正常工作阶段时框架预应力锚杆微型钢管桩与土体相互作用的计算模型,并利用位移法和有限差分法进行求解;借助ADINA有限元软件对该联合支护结构的支护效果和力学特性进行分析,将理论值与模拟值进行对比。结果表明:(1)理论计算结果与数值模拟结果基本吻合,验证了计算模型和分析方法的合理性;(2)与所提出的理论计算方法所得的结果相比,常规不考虑结构间牵连作用计算得到的框架柱内力较小,以此为设计依据使框架柱偏于不安全,而常规计算得到的微型钢管桩内力值较大,使设计过于保守;(3)与桩锚支护和地下连续墙支护结构相比,该联合支护结构可以有效的控制基坑变形且内力分布更加合理,体现了该联合支护结构优越的支护特性,可为类似深基坑支护结构的设计提供理论依据和参考。
Aiming to solve the difficulties in the construction of deep foundation pits such as narrow construction site,unconsolidated backfill and loose soil area,a combined retaining structure of frame prestressed anchors and micro steel pipe piles was put forward,and the composition and working mechanism of the structure were discussed in detail. Based on the theory of Winkel′s elastic foundation beam,an interaction model between the combining retaining structure and the soil under the tensioning stage and the normal working stage was established,which can be solved by the displacement method and the finite difference method. The supporting effects and mechanical properties of the combined retaining structure were analyzed by the finite element software of ADINA,and comparisons between theoretical and simulation values were performed. The results show that the theoretical calculation results are basically consistent with the numerical simulation results,which verifies the rationality of the calculation model and the analysis method. Compared with the results obtained by the proposed method,the internal forces of the frame column and the micro steel pipe pile calculated without considering the inter-structure implicating effect are respectively smaller and larger,which means the former unsafe while the latter conservative. It is also shown that,compared with the pile anchor support structure or underground continuous wall support structure,the combined retaining structure can effectively control the deformation of foundation pits and the internal force distribution is more reasonable,which reflects good support performance of the combined retaining structure. The research can provide a theoretical basis and reference for the design of similar deep foundation pit support structure.
Aiming to solve the difficulties in the construction of deep foundation pits such as narrow construction site,unconsolidated backfill and loose soil area,a combined retaining structure of frame prestressed anchors and micro steel pipe piles was put forward,and the composition and working mechanism of the structure were discussed in detail. Based on the theory of Winkel′s elastic foundation beam,an interaction model between the combining retaining structure and the soil under the tensioning stage and the normal working stage was established,which can be solved by the displacement method and the finite difference method. The supporting effects and mechanical properties of the combined retaining structure were analyzed by the finite element software of ADINA,and comparisons between theoretical and simulation values were performed. The results show that the theoretical calculation results are basically consistent with the numerical simulation results,which verifies the rationality of the calculation model and the analysis method. Compared with the results obtained by the proposed method,the internal forces of the frame column and the micro steel pipe pile calculated without considering the inter-structure implicating effect are respectively smaller and larger,which means the former unsafe while the latter conservative. It is also shown that,compared with the pile anchor support structure or underground continuous wall support structure,the combined retaining structure can effectively control the deformation of foundation pits and the internal force distribution is more reasonable,which reflects good support performance of the combined retaining structure. The research can provide a theoretical basis and reference for the design of similar deep foundation pit support structure.
引文
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[9]冯申铎,姜晓光,杨志银,等.“桩(墙)-撑-锚”联合支护技术的工程应用与变形协调探讨[J].岩土工程学报,2012,34(增):456-460.(FENG Shenduo,JIANG Xiaoguang,YANG Zhiyin,et al.Application and deformation compatibility of combined support of pile(wall)-bracing-anchor[J].Chinese Journal of Geotechnical Engineering,2012,34(Supp.):456-460.(in Chinese))
[10]邵权,徐学连,徐松,等.深基坑桩锚撑组合支护结构变形影响因素的三维数值分析[J].岩土工程学报,2014,36(增2):87-91.(SHAO Quan,XU Xuelian,XU Song,et al.Three-dimensional numerical analysis of factors affecting deformation of pile-anchor-support composite retaining structures for deep foundation pits[J].Chinese Journal of Geotechnical Engineering,2014,36(Supp.2):87-91.(in Chinese))
[11]解磊,董礼.深基坑放坡-桩锚联合支护结构的监测及数值模拟[J].沈阳建筑大学学报:自然科学版,2015,31(2):228-235.(XIELei,DONG Li.Numerical simulation and monitoring of slope-pile anchor comboned support structure for deep excavation[J].Journal of Shenyang Jianzhu University:Natural Science,2015,31(2):228-235.(in Chinese))
[12]俞海波,王红雨,王卫东,等.排桩与土钉墙联合支护基坑变形数值模拟[J].长江科学院院报,2017,34(3):96-99.(YU Haibo,WANG Hongyu,WANG Weidong,et al.Numerical simulation on deformation of excavation pit supported by row piles and soil nailing[J].Journal of Yangtze River Scientific Research Institute,2017,34(3):96-99.(in Chinese))
[13]马平,申平,秦四清,等.深基坑桩锚与土钉墙联合支护的数值模拟[J].工程地质学报,2008,16(3):401-407.(MA Ping,SHENPing,QING Siqing,et al.Numerical simulation of pile-anchor and soil nailing wall composite support structure in deep foundation pit[J].Journal of Engineering Geology,2008,16(3):401-407.(in Chinese))
[14]边学成,陈云敏.列车移动荷载作用下分层地基响应特性[J].岩石力学与工程学报,2007,26(1):182-189.(BIAN Xuecheng,CHENYunmin.Characteristics of layered ground responses under train moving loads[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(1):182-189.(in Chinese))
[2]伍俊,郑全平,吴祥云.复合土钉支护技术的有限元数值模拟及工程应用[J].岩土工程学报,2005,27(4):388-392.(WU Jun,ZHENG Quanping,WU Xiangyun.Numerical simulation in finite element and engineering application of compound soil nail support technology[J].Chinese Journal of Geotechnical Engineering,2005,27(4):388-392.(in Chinese))
[3]陆瑞明,赵锡宏,马忠政,等.组合式挡墙的基坑围护非线性的空间设计计算理论和方法[J].土木工程学报,2001,34(6):80-87.(LURuiming,ZHAO Xihong,MA Zhongzheng,et al.Nonline space computation method for support structure of combined retaining wall[J].China Civil Engineering Journal,2001,34(6):80-87.(in Chinese))
[4]胡瑞,颜海春,蔡灿柳.复合土钉与桩锚联合支护的应用研究[J].建筑施工,2005,27(6):29-31.(HU Rui,YAN Haichun,CAICanliu.Application study on combined foundation pit support with composite soil nail and anchor pile[J].Building Construction,2005,27(6):29-31.(in Chinese))
[5]胡仲春,任高锋,胡逢春.基于有限元数值模拟的基坑联合支护系统分析[J].地下空间与工程学报,2011,7(增):1 648-1 652.(HUZhongchun,REN Gaofeng,HU Fengchun.Analysis of excavation combined support system based on finite element numerical simulation[J].Chinese Journal of Underground Space and Engineering,2011,7(Supp.):1 648-1 652.(in Chinese))
[6]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(15):2 585-2 592.(SUN Tiecheng,ZHANG Mingju,YANG Qian.Modeling study on composite soil nailing for deep excavation[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(15):2 585-2 592.(in Chinese))
[7]杨向前.微型桩预应力锚杆复合土钉支护结构受力变形性状模拟研究[硕士学位论文][D].郑州:郑州大学,2014.(YONG Xiangqian.Simulation study on stress deformation of mini pile prestressed anchor composite soil nailing excavations protection structure[M.S.Thesis][D].Zhengzhong:Zhengzhong University,2014.(in Chinese))
[8]王媛媛,秦四清.土钉与复合土钉支护结构数值模拟对比分析[J].工程地质学报,2006,14(2):271-275.(WANG Yuanyuan,QINSiqing.Comparison of soil nail and composite soil nail reinforcement structures using numerical smulations[J].Journal of Engineerng Geology,2006,14(2):271-275.(in Chinese))
[9]冯申铎,姜晓光,杨志银,等.“桩(墙)-撑-锚”联合支护技术的工程应用与变形协调探讨[J].岩土工程学报,2012,34(增):456-460.(FENG Shenduo,JIANG Xiaoguang,YANG Zhiyin,et al.Application and deformation compatibility of combined support of pile(wall)-bracing-anchor[J].Chinese Journal of Geotechnical Engineering,2012,34(Supp.):456-460.(in Chinese))
[10]邵权,徐学连,徐松,等.深基坑桩锚撑组合支护结构变形影响因素的三维数值分析[J].岩土工程学报,2014,36(增2):87-91.(SHAO Quan,XU Xuelian,XU Song,et al.Three-dimensional numerical analysis of factors affecting deformation of pile-anchor-support composite retaining structures for deep foundation pits[J].Chinese Journal of Geotechnical Engineering,2014,36(Supp.2):87-91.(in Chinese))
[11]解磊,董礼.深基坑放坡-桩锚联合支护结构的监测及数值模拟[J].沈阳建筑大学学报:自然科学版,2015,31(2):228-235.(XIELei,DONG Li.Numerical simulation and monitoring of slope-pile anchor comboned support structure for deep excavation[J].Journal of Shenyang Jianzhu University:Natural Science,2015,31(2):228-235.(in Chinese))
[12]俞海波,王红雨,王卫东,等.排桩与土钉墙联合支护基坑变形数值模拟[J].长江科学院院报,2017,34(3):96-99.(YU Haibo,WANG Hongyu,WANG Weidong,et al.Numerical simulation on deformation of excavation pit supported by row piles and soil nailing[J].Journal of Yangtze River Scientific Research Institute,2017,34(3):96-99.(in Chinese))
[13]马平,申平,秦四清,等.深基坑桩锚与土钉墙联合支护的数值模拟[J].工程地质学报,2008,16(3):401-407.(MA Ping,SHENPing,QING Siqing,et al.Numerical simulation of pile-anchor and soil nailing wall composite support structure in deep foundation pit[J].Journal of Engineering Geology,2008,16(3):401-407.(in Chinese))
[14]边学成,陈云敏.列车移动荷载作用下分层地基响应特性[J].岩石力学与工程学报,2007,26(1):182-189.(BIAN Xuecheng,CHENYunmin.Characteristics of layered ground responses under train moving loads[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(1):182-189.(in Chinese))