基于厚壁圆筒模型的筋箍碎石桩沉降计算
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摘要
为解决现有方法难以考虑加筋材料实际受力状态而低估筋箍碎石桩复合地基沉降的问题,假设桩土等应变且均为线弹性材料,选取单桩有效加固单元整体作为分析对象,其中碎石桩同时受到加筋材料和土环的约束作用,而土环则可以考虑为同时受到单桩有效加固范围外土体的静止土压力和内部碎石桩鼓胀压力共同作用的厚壁圆筒,再结合广义胡克定律得到应力应变关系,进而导出了筋箍碎石桩复合地基沉降计算的新方法.采用工程实例验证并与已有方法进行比较,同时分析了外荷载水平、置换率对复合地基总沉降和桩土应力比的影响.与已有方法相比,该方法可以使上部荷载和筋箍碎石桩侧向受力变形联动进而调整加筋材料内力,从而更符合筋箍碎石桩实际受力变形情况,计算值与实测值相对误差为+5.70%,与现有保守计算方法相比,误差最小.参数分析表明:置换率对于控制复合地基总沉降具有重要作用,外荷载一定时复合地基总沉降与桩土应力比均随着置换率提高而减小.
The existing methods can hardly consider the actual state of geogrid ribs under loading,which can cause underestimating the settlement of the geogrid-encased stone column(GESC)composite foundation.The effective reinforced unit cell was employed as the analysis object,while GESC together with soil was assumed in constant strain distribution and as linear elastic materials.Stone column was constrained by geogrid and earth ring at the same time,while the earth ring can be considered as a ring with earth pressure at rest provided by soil outside and bulging pressure caused by the stone column installed inside. Hook's law was then introduced to gain the stress-strain formula of the unit cell. A different method of settlement calculation for GESC composite foundation was established.The rationality of the results of this method was verified by an engineering example and was compared with the existing method.The result demonstrates that the method agrees well with the engineering example.Compared with the existing method,the relative error between the calculated value and measured value is +5.70%,which demonstrates that the method presented in this paper is safer and more accurate as a result of combined top loading and lateral deformation of GESC together. The parametric study shows that the replacement ratio has a significant influence on controlling settlement of composite foundation,and increasing the replacement ratio can effectively reduce the pilesoil ratio and settlement of composite foundation when a certain level load is applied.
The existing methods can hardly consider the actual state of geogrid ribs under loading,which can cause underestimating the settlement of the geogrid-encased stone column(GESC)composite foundation.The effective reinforced unit cell was employed as the analysis object,while GESC together with soil was assumed in constant strain distribution and as linear elastic materials.Stone column was constrained by geogrid and earth ring at the same time,while the earth ring can be considered as a ring with earth pressure at rest provided by soil outside and bulging pressure caused by the stone column installed inside. Hook's law was then introduced to gain the stress-strain formula of the unit cell. A different method of settlement calculation for GESC composite foundation was established.The rationality of the results of this method was verified by an engineering example and was compared with the existing method.The result demonstrates that the method agrees well with the engineering example.Compared with the existing method,the relative error between the calculated value and measured value is +5.70%,which demonstrates that the method presented in this paper is safer and more accurate as a result of combined top loading and lateral deformation of GESC together. The parametric study shows that the replacement ratio has a significant influence on controlling settlement of composite foundation,and increasing the replacement ratio can effectively reduce the pilesoil ratio and settlement of composite foundation when a certain level load is applied.
引文
[1]唐承铁,刘猛.加筋碎石桩格栅强度设计初探[J].公路工程,2012,37(6):25—28.TANG C T,LIU M.A tentative exploration on the strength design of the geogrid in geosynthetic-encased stone columns[J]. HighwayEngineering,2012,37(6):25—28.(In Chinese)
[2]陈庆.格栅套筒加筋碎石桩复合地基承载力计算方法研究[D].长沙:湖南大学土木工程学院,2011:11—12.CHEN Q.The research on the calculation method for eosyntheticencased gravel pile composite foundation[D].Changsha:College of Civil Engineering,Hunan University,2011:11—12.(In Chinese)
[3]龚晓南.复合地基理论及工程应用[M].北京:中国建筑工业出版社,2007:130-131.GONG X N. Theory and engineering application of composite foundation[M].Beijing:China Architecture and Building Press,2007:130—131.(In Chinese)
[4]OMINE K,OHNO S.Deformation analysis of composite ground by homogenization method[C]//Proceedings of the Fourteenth International Conference on Soil Mechanics and Foundation Engineering.Rotterdam:Balkema A A,1997:719—722.
[5]AFSHAR J N,GHAZAVI M. Experimental studies on bearing capacity of geosynthetic reinforced stone columns[J]. Arabian Journal for Science&Engineering,2014,39(3):1559—1571.
[6]GU M,ZHAO M,ZHANG L,et al.Effects of geogrid encasement on lateral and vertical deformations of stone columns in model tests[J].Geosynthetics International,2016,23(2):100—112.
[7]ALMEIDA M S S,HOSSEINPOUR I,RICCIO M,et al.Behavior of geotextile-encased granular columns supporting test embankment on soft deposit[J].Journal of Geotechnical&Geoenvironmental Engineering,2015,141(3):04014116.
[8]HONG Y S,Wu C S,YU Y S.Model tests on geotextile-encased granular columns under 1-g and undrained conditions[J].Geotextiles&Geomembranes,2016,44(1):13—27.
[9]李小青,周伟.考虑桩土接触特性的复合地基承载机理的数值分析研究[J].岩土工程学报,2006,28(4):529-532.LI X Q,ZHOU W. Numerical analysis on bearing capacity of composite foundation in consideration of contacting characteristics of pile-soil interface[J]. Chinese Journal of Geotechnical Engineering,2006,28(4):529—532.(In Chinese)
[10]崔澈,张志耕,闫澍旺.碎石桩联合土工格栅复合地基处理湿地软基的机制研究[J].岩土力学,2009,30(6):1764—1768.CUI W,ZHANG Z G,YAN S W.Mechanism of composite ground with stone columns and geogrid in wetland[J]. Rock and Soil Mechanics,2009,30(6):1764—1768.(In Chinese)
[11]YOO C.Settlement behavior of embankment on geosynthetic-encased stone column installed soft ground—A numerical investigation[J].Geotextiles&Geomembranes,2015,43(6):484—492.
[12]KHABBAZIAN M,KALIAKIN V N,MEEHAN C L.Column supported embankments with geosynthetic encased columns:validity of the unit cell concept[J].Geotechnical and Geological Engineering,2015,33(3):425—442.
[13]HOSSEINPOUR I,RICCIO M,ALMEIDA M S S.Numerical evaluation of a granular column reinforced by geosynthetics using en-casement and laminated disks[J].Geotextiles&Geomembranes,2014,42(4):363—373.
[14]曹文贵,王江营,罗忠涛,等.考虑桩-土滑移的柔性基础下复合地基沉降分析方法[J].中国公路学报,2012,25(6):9-16.CAO W G,WANG J Y,LUO Z T,et al. Settlement calculation method for composite ground considering pile-soil slip under flexible foundation[J]. China Journal of Highway and Transport,2012,25(6):9—16.(In Chinese)
[15]曹文贵,杨泽华.柔性基础下碎石桩加筋复合地基沉降分析方法[J].岩土工程学报.2012,34(11):1997—2004.CAO W G,YANG Z H.Method for analyzing settlement of reinforced-gravel-pile composite ground under flexible foundation[J].Chinese Journal of Geotechnical Engineering, 2012, 34(11):1997—2004.(In Chinese)
[16]曹文贵,赵聚才,贺敏,等.柔性基础下筋箍碎石桩复合地基变形机理及其沉降分析方法[J].岩土工程学报,2014,36(5):818—826.CAO W G,ZHAO J C,HE M,et al. Deformation mechanism and settlement analysis method of reinforced-hoop-gravel-pile composite ground under flexible foundation[J]. Chinese Journal of Geotechnical Engineering,2014,36(5):818—826.(In Chinese)
[17]曹文贵,唐旖旎,王江营.基于孔隙介质模型的散体材料桩复合地基沉降分层总和分析方法[J].湖南大学学报(自然科学版),2014,41(11):87—95.CAO W G,TANG Y N,WAND J Y.A layer-wise summation analysis method for the settlement of composite ground with friable material piles based on porous medium model[J].Journal of Hunan University(Natural Sciences),2014,41(11):87—95.(In Chinese)
[18]ZHANG L,ZHAO M H.Deformation analysis of geotextile-encased stone columns[J]. International Journal of Geomechanics,2015,15(3):04014053.
[19]张玲,赵明华.考虑鼓胀变形的散体材料桩复合地基沉降计算[J].湖南大学学报(自然科学版),2016,43(5):120-124.ZHANG L,ZHAO M H.Settlement calculation of granular material pile composite foundation with consideration of lateral bulging[J].Journal of Hunan University(Natural Sciences),2016,43(5):120—124.(In Chinese)
[20]ALAMGIR M,MIURA N,POOROOSHASB H B.Deformation analysis of soft ground reinforced by columnar inclusions[J].Computers and Geotechnics,1996,18(4):267—290.
[21]章定文,刘松玉.路堤荷载下柔性桩复合地基沉降实用计算方法[J].岩土力学,2007,28(6):1133—1138.ZHANG D W,LIU S Y.Practical method for settlement calculation of flexible columns composite foundation under embankment[J].Rock and Soil Mechanics,2007,28(6):1133—1138.(In Chinese)
[22]GB50007—2011建筑地基基础设计规范[S].北京:中国建筑工业出版社,2011:28—30.GB50007—2011Code for design of building foundation[S].Beijing:China Architecture&Building Press,2011:28—30.(In Chinese)
[23]CASTRO J. An analytical solution for the settlement of stone columns beneath rigid footings[J]. Acta Geotechnica,2014,11(2):1—16.
[24]DEBNATH P,DEY A K. Bearing capacity of geogrid reinforced sand over encased stone columns in soft clay[J]. Geotextiles&Geomembranes,2017,45(6):653—664.
[25]CASTRO J.Groups of encased stone columns:influence of column length and arrangement[J].Geotextiles&Ceomembranes,2017,45(2):68—80.
[26]徐秉业,刘信声.应用弹塑性力学[M].北京:清华大学出版社,1995:188—191.XU B Y,LIU X S.Applied elastic and plastic mechanics[M].Beijing:Tsinghua University Press,1995:188—191.(In Chinese)
[27]黄兵.GSPS软基加固系统机理及其在成都绕城高速公路的应用研究[D].成都:西南交通大学土木工程学院,2002:41—51.HUANG B.The mechanism of GSPS soft ground treatment system and its application in Chengdu City Highway[D].Chengdu:School of Civil Engineering,Southwest Jiaotong University,2002:41—51.(In Chinese)
[28]张赞威.筋箍碎石桩复合地基承载机理及其变形分析[D].长沙:湖南大学土木工程学院,2014:52—53.ZHANG Z W. The analysis of geotextile encased stone columns composite foundation bear-deformation mechanism[D].Changsha:College of Civil Engineering,Hunan University,2014:52—53.(In Chinese)
[2]陈庆.格栅套筒加筋碎石桩复合地基承载力计算方法研究[D].长沙:湖南大学土木工程学院,2011:11—12.CHEN Q.The research on the calculation method for eosyntheticencased gravel pile composite foundation[D].Changsha:College of Civil Engineering,Hunan University,2011:11—12.(In Chinese)
[3]龚晓南.复合地基理论及工程应用[M].北京:中国建筑工业出版社,2007:130-131.GONG X N. Theory and engineering application of composite foundation[M].Beijing:China Architecture and Building Press,2007:130—131.(In Chinese)
[4]OMINE K,OHNO S.Deformation analysis of composite ground by homogenization method[C]//Proceedings of the Fourteenth International Conference on Soil Mechanics and Foundation Engineering.Rotterdam:Balkema A A,1997:719—722.
[5]AFSHAR J N,GHAZAVI M. Experimental studies on bearing capacity of geosynthetic reinforced stone columns[J]. Arabian Journal for Science&Engineering,2014,39(3):1559—1571.
[6]GU M,ZHAO M,ZHANG L,et al.Effects of geogrid encasement on lateral and vertical deformations of stone columns in model tests[J].Geosynthetics International,2016,23(2):100—112.
[7]ALMEIDA M S S,HOSSEINPOUR I,RICCIO M,et al.Behavior of geotextile-encased granular columns supporting test embankment on soft deposit[J].Journal of Geotechnical&Geoenvironmental Engineering,2015,141(3):04014116.
[8]HONG Y S,Wu C S,YU Y S.Model tests on geotextile-encased granular columns under 1-g and undrained conditions[J].Geotextiles&Geomembranes,2016,44(1):13—27.
[9]李小青,周伟.考虑桩土接触特性的复合地基承载机理的数值分析研究[J].岩土工程学报,2006,28(4):529-532.LI X Q,ZHOU W. Numerical analysis on bearing capacity of composite foundation in consideration of contacting characteristics of pile-soil interface[J]. Chinese Journal of Geotechnical Engineering,2006,28(4):529—532.(In Chinese)
[10]崔澈,张志耕,闫澍旺.碎石桩联合土工格栅复合地基处理湿地软基的机制研究[J].岩土力学,2009,30(6):1764—1768.CUI W,ZHANG Z G,YAN S W.Mechanism of composite ground with stone columns and geogrid in wetland[J]. Rock and Soil Mechanics,2009,30(6):1764—1768.(In Chinese)
[11]YOO C.Settlement behavior of embankment on geosynthetic-encased stone column installed soft ground—A numerical investigation[J].Geotextiles&Geomembranes,2015,43(6):484—492.
[12]KHABBAZIAN M,KALIAKIN V N,MEEHAN C L.Column supported embankments with geosynthetic encased columns:validity of the unit cell concept[J].Geotechnical and Geological Engineering,2015,33(3):425—442.
[13]HOSSEINPOUR I,RICCIO M,ALMEIDA M S S.Numerical evaluation of a granular column reinforced by geosynthetics using en-casement and laminated disks[J].Geotextiles&Geomembranes,2014,42(4):363—373.
[14]曹文贵,王江营,罗忠涛,等.考虑桩-土滑移的柔性基础下复合地基沉降分析方法[J].中国公路学报,2012,25(6):9-16.CAO W G,WANG J Y,LUO Z T,et al. Settlement calculation method for composite ground considering pile-soil slip under flexible foundation[J]. China Journal of Highway and Transport,2012,25(6):9—16.(In Chinese)
[15]曹文贵,杨泽华.柔性基础下碎石桩加筋复合地基沉降分析方法[J].岩土工程学报.2012,34(11):1997—2004.CAO W G,YANG Z H.Method for analyzing settlement of reinforced-gravel-pile composite ground under flexible foundation[J].Chinese Journal of Geotechnical Engineering, 2012, 34(11):1997—2004.(In Chinese)
[16]曹文贵,赵聚才,贺敏,等.柔性基础下筋箍碎石桩复合地基变形机理及其沉降分析方法[J].岩土工程学报,2014,36(5):818—826.CAO W G,ZHAO J C,HE M,et al. Deformation mechanism and settlement analysis method of reinforced-hoop-gravel-pile composite ground under flexible foundation[J]. Chinese Journal of Geotechnical Engineering,2014,36(5):818—826.(In Chinese)
[17]曹文贵,唐旖旎,王江营.基于孔隙介质模型的散体材料桩复合地基沉降分层总和分析方法[J].湖南大学学报(自然科学版),2014,41(11):87—95.CAO W G,TANG Y N,WAND J Y.A layer-wise summation analysis method for the settlement of composite ground with friable material piles based on porous medium model[J].Journal of Hunan University(Natural Sciences),2014,41(11):87—95.(In Chinese)
[18]ZHANG L,ZHAO M H.Deformation analysis of geotextile-encased stone columns[J]. International Journal of Geomechanics,2015,15(3):04014053.
[19]张玲,赵明华.考虑鼓胀变形的散体材料桩复合地基沉降计算[J].湖南大学学报(自然科学版),2016,43(5):120-124.ZHANG L,ZHAO M H.Settlement calculation of granular material pile composite foundation with consideration of lateral bulging[J].Journal of Hunan University(Natural Sciences),2016,43(5):120—124.(In Chinese)
[20]ALAMGIR M,MIURA N,POOROOSHASB H B.Deformation analysis of soft ground reinforced by columnar inclusions[J].Computers and Geotechnics,1996,18(4):267—290.
[21]章定文,刘松玉.路堤荷载下柔性桩复合地基沉降实用计算方法[J].岩土力学,2007,28(6):1133—1138.ZHANG D W,LIU S Y.Practical method for settlement calculation of flexible columns composite foundation under embankment[J].Rock and Soil Mechanics,2007,28(6):1133—1138.(In Chinese)
[22]GB50007—2011建筑地基基础设计规范[S].北京:中国建筑工业出版社,2011:28—30.GB50007—2011Code for design of building foundation[S].Beijing:China Architecture&Building Press,2011:28—30.(In Chinese)
[23]CASTRO J. An analytical solution for the settlement of stone columns beneath rigid footings[J]. Acta Geotechnica,2014,11(2):1—16.
[24]DEBNATH P,DEY A K. Bearing capacity of geogrid reinforced sand over encased stone columns in soft clay[J]. Geotextiles&Geomembranes,2017,45(6):653—664.
[25]CASTRO J.Groups of encased stone columns:influence of column length and arrangement[J].Geotextiles&Ceomembranes,2017,45(2):68—80.
[26]徐秉业,刘信声.应用弹塑性力学[M].北京:清华大学出版社,1995:188—191.XU B Y,LIU X S.Applied elastic and plastic mechanics[M].Beijing:Tsinghua University Press,1995:188—191.(In Chinese)
[27]黄兵.GSPS软基加固系统机理及其在成都绕城高速公路的应用研究[D].成都:西南交通大学土木工程学院,2002:41—51.HUANG B.The mechanism of GSPS soft ground treatment system and its application in Chengdu City Highway[D].Chengdu:School of Civil Engineering,Southwest Jiaotong University,2002:41—51.(In Chinese)
[28]张赞威.筋箍碎石桩复合地基承载机理及其变形分析[D].长沙:湖南大学土木工程学院,2014:52—53.ZHANG Z W. The analysis of geotextile encased stone columns composite foundation bear-deformation mechanism[D].Changsha:College of Civil Engineering,Hunan University,2014:52—53.(In Chinese)
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