框架墩式码头群桩桩基承载性能研究
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摘要
本文系统阐述了嵌岩群桩的承载机理和群桩的沉降计算方法,结合纳溪沟码头工程,借助ABAQUS三维有限元数值模拟方法建立了嵌岩群桩的理想计算模型,对影响嵌岩群桩承载性能的因素:桩长、桩径、基岩强度、嵌岩深度等进行了深入的分析研究,得出以下结论:
(1)在有限元数值模拟结果中,中心桩与角桩的桩顶沉降量以及桩顶水平位移差值较小,获知嵌岩群桩的群桩效应并不明显。
(2)群桩在竖向荷载作用下,刚性承台与桩共同承担荷载,承台周边应力大于承台中部应力;荷载传到下部各桩上时,角桩桩顶荷载均比中心桩桩顶荷载大。
(3)在同一荷载条件下,中心桩和角桩的桩径越大,桩顶沉降越小,沉降曲线趋于一定值;当桩径达到1.8m以后,桩径对桩顶沉降的影响减小,且中心桩与角桩的沉降差值逐渐减小为零。
(4)嵌岩深度小于3D时,群桩沉降量和水平位移变化较大,嵌岩深度大于5D以后,群桩沉降和水平位移分别趋于一定值。增加嵌岩深度可以有效减少群桩桩基沉降量和水平位移,嵌岩深度超过5D时,再增加嵌岩深度对群桩稳定性没有明显的改善作用。
It was stated the load-bearing mechanism and settlement calculation methods about rock-socketed pile group. Taking the wharf of Naxigou project and based on establishing the ideal calculation model on rock-socketed pile group by the means of 3-d finite element numerical simulation with ABAQUS, it was carried out the analysis on the influence factors of the bearing capacity of rock-socketed pile, those factors are pile length, pile diameter, the bedrock strength, rock-socketed depth, etc. The main conclusions as follows:
(1) From the results of finite element numerical simulation, it can be obtained that the vertical settlement and horizontal displacement of central pile are respectively close to that of corner pile. It was shown that the efficiency of rock-socketed pile groups is not obvious.
(2) The rigid cap-pile can supports vertical load joined with piles. The stress around the cap-pile is greater than that in the middle. The load bearing by the corner pile is more than that by the central pile.
(3) Under the same load conditions, the more the diameter of both central and corner piles, the smaller the settlement of pile top, and in fall the settlement curve tended to a constant. When the pile diameter is to 1.8m, the influence was weakened. The settlement of both central pile and corner pile were zero gradually.
(4) When the rock-socketed depth is less than 3D, the settlement and horizontal displacement of pile group are changed more; when the rock-socketed depth is more than 5D, the settlement and horizontal displacement of pile group respectively tend to constants. Increasing rock-socketed depth can effectively reduce settlement and horizontal displacement of pile group. If rock-socketed depth gets more than 5D, increasing rock-socketed depth will have no obvious improvement to stabilize pile group.
(1)在有限元数值模拟结果中,中心桩与角桩的桩顶沉降量以及桩顶水平位移差值较小,获知嵌岩群桩的群桩效应并不明显。
(2)群桩在竖向荷载作用下,刚性承台与桩共同承担荷载,承台周边应力大于承台中部应力;荷载传到下部各桩上时,角桩桩顶荷载均比中心桩桩顶荷载大。
(3)在同一荷载条件下,中心桩和角桩的桩径越大,桩顶沉降越小,沉降曲线趋于一定值;当桩径达到1.8m以后,桩径对桩顶沉降的影响减小,且中心桩与角桩的沉降差值逐渐减小为零。
(4)嵌岩深度小于3D时,群桩沉降量和水平位移变化较大,嵌岩深度大于5D以后,群桩沉降和水平位移分别趋于一定值。增加嵌岩深度可以有效减少群桩桩基沉降量和水平位移,嵌岩深度超过5D时,再增加嵌岩深度对群桩稳定性没有明显的改善作用。
It was stated the load-bearing mechanism and settlement calculation methods about rock-socketed pile group. Taking the wharf of Naxigou project and based on establishing the ideal calculation model on rock-socketed pile group by the means of 3-d finite element numerical simulation with ABAQUS, it was carried out the analysis on the influence factors of the bearing capacity of rock-socketed pile, those factors are pile length, pile diameter, the bedrock strength, rock-socketed depth, etc. The main conclusions as follows:
(1) From the results of finite element numerical simulation, it can be obtained that the vertical settlement and horizontal displacement of central pile are respectively close to that of corner pile. It was shown that the efficiency of rock-socketed pile groups is not obvious.
(2) The rigid cap-pile can supports vertical load joined with piles. The stress around the cap-pile is greater than that in the middle. The load bearing by the corner pile is more than that by the central pile.
(3) Under the same load conditions, the more the diameter of both central and corner piles, the smaller the settlement of pile top, and in fall the settlement curve tended to a constant. When the pile diameter is to 1.8m, the influence was weakened. The settlement of both central pile and corner pile were zero gradually.
(4) When the rock-socketed depth is less than 3D, the settlement and horizontal displacement of pile group are changed more; when the rock-socketed depth is more than 5D, the settlement and horizontal displacement of pile group respectively tend to constants. Increasing rock-socketed depth can effectively reduce settlement and horizontal displacement of pile group. If rock-socketed depth gets more than 5D, increasing rock-socketed depth will have no obvious improvement to stabilize pile group.
引文
[1]刘利民,舒翔,熊巨华.桩基工程的理论进展与工程实践.中国建材工业出版社
[2]林天健,熊厚金,王利群.桩基础设计指南.中国建筑工业出版社
[3]杨克己.实用桩基工程.人民交通出版社
[4] ABAQUS在岩土工程中的应用.中国水利水电出版社
[5]刘展.ABAQUS6.6基础教程与实例详解.中国水利水电出版社.
[6]何国峰.贵州地区嵌岩群桩承载性状与优化设计理论研究
[7]赵丗航.大直径嵌岩桩使用性能及其应用研究
[8]凡建伟.柔性大直径水平受荷桩承载特性及计算方法研究.
[9]梁丰收.码头岸坡被动桩工作特性及岸坡桩基相互作用分析.
[10]林志勇,戴自航,苏美选.群桩竖向荷载-沉降特性影响因素的数值分析[J].福州大学学报2009年10月第5期
[11]史佩栋.超高层建筑物下嵌岩桩的荷载传递特性的长期观测.中国建筑学会地基基础学术委员会论文集.太原:山西高校联合出版社.1992
[12]明可前.嵌岩桩的受力机理分析.岩土力学.1998,Vol.19.No.1
[13]孙丽芳,钱秀清.嵌岩桩在港口工程中的应用.江苏交通科技.1999(4)
[14]史佩栋,梁晋渝.嵌岩桩竖向承载力的研究.岩土工程学报.1994.No.4
[15]刘树亚.嵌岩桩-土-岩共同作用分析方法.土工基础.2000.No.2S
[16]中华人民共和国建设部.建筑地基基础设计规范(GB 50007-2002).北京:中国建筑工业出版社.2002
[17]中华人民共和国交通部部标准.公路桥涵地基与基础设计规范(JTJ024—85).北京:人民交通出版社.1985
[18]《铁路桥涵设计规范》(TBJ2-96).北京:人民交通出版社.1997
[19]国家标准《建筑桩基技术规范》(JGJ94-94)北京:中国建筑工业出版社.1995
[20]中华人民共和国行业标准《港口工程嵌岩桩设计与施工规程》(JTJ285-2000)北京:人民交通出版社.2001
[21]中华人民共和国行业标准《港口工程荷载规范》(JTJ215-98)北京:人民交通出版社.1999
[22]水利水电科学研究院等合编.岩石力学参数手册[M].北京:水利电力出版社,1991
[23]水利水电科学研究院.桩基工程手册[M].北京:中国建筑工业出版社,1995
[24] Chun.F.L.Load transfer behavior of Rock Socketed Piles.Journal of Geotechnical Engineering.1989.115(6).176～181
[25] McVay.M.C.Williams R C.Design of socketed drilled shafts in limestone.Journal of Geotechnical Engineering.1992.118(10).194～197
[26] Osterberg J D,Gill S A.Load transfer mechanism for piers socketed in hard soils or rock.Montreal P Q.1973.(3).235～262
[27] Ian.W.Johnston,Thomas.S.K.L.Shear behavior of regular triangular concrete rock joints-analysis.Journal of Geotechnical Engineering.1989.115(5).63～68
[28] coyle,H.M.,and Reese,L.C.load transfer for piles in sands.J.of SMFE div.,ASCE,Vo1.97.No.SM2,1996:1-25
[29] Horikoshi,K&M.F.Randolph.A contribution to optimum design of piled rafts Geotechnique,48, No.3,1998:301-317
[30]中国建筑科学研究院等.建筑桩基技术规范(建设部批准),1995
[31]贾庆生.桩基水平承载力标准值与m值确定.桩基技术新进展学术讨论会论文集,1991.6
[32]高大钊,孙钧.岩土工程的回顾与前瞻.北京:人民交通出版社.2001.262～263
[33]俞炯奇,张土乔,龚晓南.钻孔嵌岩灌注桩承载特性浅析.工业建筑.1999.8(25).38～43
[34]吴鹏.刚性承台超大群桩承载性状的三维有限元分析.铁道科学与工程学报.2007.4 Vol.4 No.2
[2]林天健,熊厚金,王利群.桩基础设计指南.中国建筑工业出版社
[3]杨克己.实用桩基工程.人民交通出版社
[4] ABAQUS在岩土工程中的应用.中国水利水电出版社
[5]刘展.ABAQUS6.6基础教程与实例详解.中国水利水电出版社.
[6]何国峰.贵州地区嵌岩群桩承载性状与优化设计理论研究
[7]赵丗航.大直径嵌岩桩使用性能及其应用研究
[8]凡建伟.柔性大直径水平受荷桩承载特性及计算方法研究.
[9]梁丰收.码头岸坡被动桩工作特性及岸坡桩基相互作用分析.
[10]林志勇,戴自航,苏美选.群桩竖向荷载-沉降特性影响因素的数值分析[J].福州大学学报2009年10月第5期
[11]史佩栋.超高层建筑物下嵌岩桩的荷载传递特性的长期观测.中国建筑学会地基基础学术委员会论文集.太原:山西高校联合出版社.1992
[12]明可前.嵌岩桩的受力机理分析.岩土力学.1998,Vol.19.No.1
[13]孙丽芳,钱秀清.嵌岩桩在港口工程中的应用.江苏交通科技.1999(4)
[14]史佩栋,梁晋渝.嵌岩桩竖向承载力的研究.岩土工程学报.1994.No.4
[15]刘树亚.嵌岩桩-土-岩共同作用分析方法.土工基础.2000.No.2S
[16]中华人民共和国建设部.建筑地基基础设计规范(GB 50007-2002).北京:中国建筑工业出版社.2002
[17]中华人民共和国交通部部标准.公路桥涵地基与基础设计规范(JTJ024—85).北京:人民交通出版社.1985
[18]《铁路桥涵设计规范》(TBJ2-96).北京:人民交通出版社.1997
[19]国家标准《建筑桩基技术规范》(JGJ94-94)北京:中国建筑工业出版社.1995
[20]中华人民共和国行业标准《港口工程嵌岩桩设计与施工规程》(JTJ285-2000)北京:人民交通出版社.2001
[21]中华人民共和国行业标准《港口工程荷载规范》(JTJ215-98)北京:人民交通出版社.1999
[22]水利水电科学研究院等合编.岩石力学参数手册[M].北京:水利电力出版社,1991
[23]水利水电科学研究院.桩基工程手册[M].北京:中国建筑工业出版社,1995
[24] Chun.F.L.Load transfer behavior of Rock Socketed Piles.Journal of Geotechnical Engineering.1989.115(6).176～181
[25] McVay.M.C.Williams R C.Design of socketed drilled shafts in limestone.Journal of Geotechnical Engineering.1992.118(10).194～197
[26] Osterberg J D,Gill S A.Load transfer mechanism for piers socketed in hard soils or rock.Montreal P Q.1973.(3).235～262
[27] Ian.W.Johnston,Thomas.S.K.L.Shear behavior of regular triangular concrete rock joints-analysis.Journal of Geotechnical Engineering.1989.115(5).63～68
[28] coyle,H.M.,and Reese,L.C.load transfer for piles in sands.J.of SMFE div.,ASCE,Vo1.97.No.SM2,1996:1-25
[29] Horikoshi,K&M.F.Randolph.A contribution to optimum design of piled rafts Geotechnique,48, No.3,1998:301-317
[30]中国建筑科学研究院等.建筑桩基技术规范(建设部批准),1995
[31]贾庆生.桩基水平承载力标准值与m值确定.桩基技术新进展学术讨论会论文集,1991.6
[32]高大钊,孙钧.岩土工程的回顾与前瞻.北京:人民交通出版社.2001.262～263
[33]俞炯奇,张土乔,龚晓南.钻孔嵌岩灌注桩承载特性浅析.工业建筑.1999.8(25).38～43
[34]吴鹏.刚性承台超大群桩承载性状的三维有限元分析.铁道科学与工程学报.2007.4 Vol.4 No.2