地埋管线周围土体抗力系数的正交各向异性解析分析
|
摘要
地埋管线周围土体抗力系数的各向异性及合理取值问题的解决,对于市政或海底管线的设计和评估是至关重要的。考虑管线部分或完全埋置以及管土刚度比的变化,综合运用传递矩阵法和解析类比法得到竖向及水平抗力系数;轴向抗力系数采用剪切位移法(部分埋置)或镜像法(完全埋置)求解。算例验证了抗力系数取值方法的合理性,并针对3种地基分布形式分析了参数变化下抗力系数取值的差异性。结果表明,抗力系数均随着管线埋径比的增大而增大且埋径比达到20后趋于稳定值,竖向及水平抗力系数随着管土刚度比的增大而减小;均质半无限地基中轴向抗力系数小于竖向抗力系数,管线部分埋置时水平与竖向抗力系数的比值小于1,而完全埋置时其值大于1且埋径比达到20后会趋近于1;管线下方土体的有限压缩特性对竖向及水平抗力系数均有明显影响,且竖向更为显著;抗力系数的简化均质解与成层解相差较大,均质解偏大(上软下硬地层)或偏小(上硬下软地层),分层特性明显时应采用成层解。
For the design and assessment of municipal and submarine pipelines,it is vital to solve the problems of the anisotropy and determination of the soil resistance coefficients around buried pipelines. Vertical and horizontal resistance coefficients were obtained by using transfer matrix method and analogy method,considering partial or complete embedment of the pipeline and change of the pipe-soil stiffness ratio,and axial resistance coefficient was solved by using shear displacement method and image method respectively corresponding to partially buried and completely buried cases. The rationality of the method for calculating the resistance coefficients was verified via numerical examples,and the differences in the values of the resistance coefficients caused by the change of parameters were analyzed for three typical foundation distribution forms. The results show that the resistance coefficients in three directions increase with increasing the buried depth-diameter ratio and tend to be stable with the buried depth-diameter ratio reaching 20,and that the vertical and horizontal resistance coefficients decrease with rising the pipe-soil stiffness ratio. In homogeneous semi-infinite soil,the axial resistance coefficient is less than the vertical resistance coefficient. The ratio of the horizontal resistance coefficient to the vertical resistance coefficient is less than 1 for the partially buried pipeline,but,for the completely buried pipeline,more than 1 and approaches 1 with a buried depth-diameter ratio of 20. The finite compression characteristic of soil under the pipeline has obvious influence on the vertical and horizontal resistance coefficients,and the influence on the former is more significance. The vertical and horizontal resistance coefficients obtained by simplified homogenization method are obviously different from the stratified solutions proposed in this paper. Corresponding to the cases of an upper-soft and lower-hard stratum and an upper-hard and lower-soft stratum,the simplified homogeneous values of the resistance coefficients are respectively bigger or smaller than the stratified solutions.
For the design and assessment of municipal and submarine pipelines,it is vital to solve the problems of the anisotropy and determination of the soil resistance coefficients around buried pipelines. Vertical and horizontal resistance coefficients were obtained by using transfer matrix method and analogy method,considering partial or complete embedment of the pipeline and change of the pipe-soil stiffness ratio,and axial resistance coefficient was solved by using shear displacement method and image method respectively corresponding to partially buried and completely buried cases. The rationality of the method for calculating the resistance coefficients was verified via numerical examples,and the differences in the values of the resistance coefficients caused by the change of parameters were analyzed for three typical foundation distribution forms. The results show that the resistance coefficients in three directions increase with increasing the buried depth-diameter ratio and tend to be stable with the buried depth-diameter ratio reaching 20,and that the vertical and horizontal resistance coefficients decrease with rising the pipe-soil stiffness ratio. In homogeneous semi-infinite soil,the axial resistance coefficient is less than the vertical resistance coefficient. The ratio of the horizontal resistance coefficient to the vertical resistance coefficient is less than 1 for the partially buried pipeline,but,for the completely buried pipeline,more than 1 and approaches 1 with a buried depth-diameter ratio of 20. The finite compression characteristic of soil under the pipeline has obvious influence on the vertical and horizontal resistance coefficients,and the influence on the former is more significance. The vertical and horizontal resistance coefficients obtained by simplified homogenization method are obviously different from the stratified solutions proposed in this paper. Corresponding to the cases of an upper-soft and lower-hard stratum and an upper-hard and lower-soft stratum,the simplified homogeneous values of the resistance coefficients are respectively bigger or smaller than the stratified solutions.
引文
[1]GAZETAS G,DOBRY R,TASSOULAS J L.Vertical response of arbitrarily shaped embedded foundations[J].Journal of Geotechnical Engineering,1985,111(6):750-771.
[2]GAZETAS G,TASSOULAS J L.Horizontal stiffness of arbitrarily shaped embedded foundations[J].Journal of Geotechnical Engineering,1987,113(5):440-457.
[3]GUHA I,RANDOLPH M F,WHITE D J.Evaluation of elastic stiffness parameters for pipeline-soil interaction[J].Journal of Geotechnical and Geoenvironmental Engineering,2016,142(6):04016009.
[4]SHARMA J R.Development of a model for estimation of buried large diameter thin-walled steel pipe deflection due to external loads[Ph.D.Thesis][D].Arlington:University of Texas at Arlington,2013.
[5]WHIDDEN W R.Buried flexible steel pipe:design and structural analysis[M].Virginia,USA:ASCE,2009:73-86.
[6]BIOT M A.Bending of an infinite beam on an elastic foundation[J].Journal of Applied Mechanics,ASME,1937,59:A1-A7.
[7]VESIC A B.Bending of beams resting on isotropic elastic solid[J].Journal of the Engineering Mechanics Division,ASCE,1961,87(2):35-53.
[8]TERZAGHI K.Evaluation of coefficients of subgrade reaction[J].Geotechnique,1955,5(4):297-326.
[9]DALOGLU A T,VALLABHAN C V G.Values of k for slab on Winkler foundation[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(5):463-471.
[10]俞剑,张陈蓉,黄茂松.被动状态下地埋管线的地基模量[J].岩石力学与工程学报,2012,31(1):123-132.(YU Jian,ZHANGChenrong,HUANG Maosong.Subgrade modulus of underground pipelines subjected to soil movements[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(1):123-132.(in Chinese))
[11]YU J,ZHANG C R,HUANG M S.Soil-pipe interaction due to tunnelling:Assessment of Winkler modulus for underground pipelines[J].Computers and Geotechnics,2013,50(5):17-28.
[12]王雨,陈文化.地层成层性对基床系数的影响分析[J].岩石力学与工程学报,2017,36(增2):4 304-4 312.(WANG Yu,CHENWenhua.Influence of soil stratification on coefficient of subgrade reaction[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(Supp.2):4 304-4 312.(in Chinese))
[13]王雨,陈文化.地埋梁与横观各向同性层状地基相互作用的广义VESIC解答[J].岩土工程学报,2018,40(12):2 241-2 248.(WANGYu,CHEN Wenhua.Generalized VESIC solution for interaction of buried beam and transversely isotropic layered soil[J].Chinese Journal of Geotechnical Engineering,2018,40(12):2 241-2 248.(in Chinese))
[14]SHELDON T,SEZEN H,MOORE I D.Beam-on-springs modeling of jointed pipe culverts[J].Journal of Performance of Constructed Facilities,2016,30(2):1-9.
[15]TIAN Y H,CASSIDY M J,GAUDIN C.Advancing pipe-soil interaction models in calcareous sand[J].Applied Ocean Research,2010,32(3):284-297.
[16]HOLDER M S,CASSIDY M J.A plasticity model for predicting the vertical and lateral behaviour of pipelines in clay soils[J].Geotechnique,2010,60(4):247-263.
[17]HMADI K E,O′ROURKE M.Soil springs for buried pipeline axial motion[J].Journal of Geotechnical Engineering,1988,114(11):1 335-1 339.
[18]MATSUBARA K,HOSHIYA M.Soil spring constants of buried pipelines for seismic design[J].Journal of Engineering Mechanics,2000,126(1):76-83.
[19]钟阳,殷建华.弹性层状体的求解方法[M].北京:科学出版社,2007:142-150.(ZHONG Yang,YIN Jianhua.Solving method of elastic layered body[M].Beijing:Science Press,2007:142-150.(in Chinese))
[20]吴为义.盾构隧道周围地下管线的性状研究[博士学位论文][D].杭州:浙江大学,2008.(WU Weiyi.Study on mechanical behaviors of buried pipelines induced by shield tunnelling construction[Ph.D.Thesis][D].Hangzhou:Zhejiang University,2008.(in Chinese))
[21]邵羽.盾构双隧道施工对临近地埋管线的影响研究[博士学位论文][D].南宁:广西大学,2017.(SHAO Yu.Mechanism behaviors of existing buried pipelines due to twin shield tunnelling[Ph.D.Thesis][D].Nanning:Guangxi University,2017.(in Chinese))
[22]WHITE D J,RANDOLPH M F.Seabed characterisation and models for pipeline-soil interaction[J].International Journal of Offshore and Polar Engineering,2007,17(3):193-204.
[23]MYLONAKIS G,GAZETAS G.Settlement and additional internal forces of grouped piles in layered soil[J].Geotechnique,1998,48(1):55-72.
[24]RANDOLPH M F,WROTH C P.Analysis of deformation of vertically loaded piles[J].Journal of the Geotechnical Engineering Division,1978,104(12):1 465-1 488.
[25]方钱宝,马建林,喻渝,等.大断面黄土隧道围岩弹性抗力系数、变形模量与压缩模量试验研究[J].岩石力学与工程学报,2009,28(增2):3 932-3 937.(FANG Qianbao,MA Jianlin,YU Yu,et al.Experimental research on elastic resistant coefficient,deformation and compressive moduli of surrounding rock in large-section loess tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp.2):3 932-3 937.(in Chinese))
[26]HALDAR S,BASU D.Analysis of beams on heterogeneous and nonlinear soil[J].International Journal of Geomechanics,2016,16(4):04016004.
[2]GAZETAS G,TASSOULAS J L.Horizontal stiffness of arbitrarily shaped embedded foundations[J].Journal of Geotechnical Engineering,1987,113(5):440-457.
[3]GUHA I,RANDOLPH M F,WHITE D J.Evaluation of elastic stiffness parameters for pipeline-soil interaction[J].Journal of Geotechnical and Geoenvironmental Engineering,2016,142(6):04016009.
[4]SHARMA J R.Development of a model for estimation of buried large diameter thin-walled steel pipe deflection due to external loads[Ph.D.Thesis][D].Arlington:University of Texas at Arlington,2013.
[5]WHIDDEN W R.Buried flexible steel pipe:design and structural analysis[M].Virginia,USA:ASCE,2009:73-86.
[6]BIOT M A.Bending of an infinite beam on an elastic foundation[J].Journal of Applied Mechanics,ASME,1937,59:A1-A7.
[7]VESIC A B.Bending of beams resting on isotropic elastic solid[J].Journal of the Engineering Mechanics Division,ASCE,1961,87(2):35-53.
[8]TERZAGHI K.Evaluation of coefficients of subgrade reaction[J].Geotechnique,1955,5(4):297-326.
[9]DALOGLU A T,VALLABHAN C V G.Values of k for slab on Winkler foundation[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(5):463-471.
[10]俞剑,张陈蓉,黄茂松.被动状态下地埋管线的地基模量[J].岩石力学与工程学报,2012,31(1):123-132.(YU Jian,ZHANGChenrong,HUANG Maosong.Subgrade modulus of underground pipelines subjected to soil movements[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(1):123-132.(in Chinese))
[11]YU J,ZHANG C R,HUANG M S.Soil-pipe interaction due to tunnelling:Assessment of Winkler modulus for underground pipelines[J].Computers and Geotechnics,2013,50(5):17-28.
[12]王雨,陈文化.地层成层性对基床系数的影响分析[J].岩石力学与工程学报,2017,36(增2):4 304-4 312.(WANG Yu,CHENWenhua.Influence of soil stratification on coefficient of subgrade reaction[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(Supp.2):4 304-4 312.(in Chinese))
[13]王雨,陈文化.地埋梁与横观各向同性层状地基相互作用的广义VESIC解答[J].岩土工程学报,2018,40(12):2 241-2 248.(WANGYu,CHEN Wenhua.Generalized VESIC solution for interaction of buried beam and transversely isotropic layered soil[J].Chinese Journal of Geotechnical Engineering,2018,40(12):2 241-2 248.(in Chinese))
[14]SHELDON T,SEZEN H,MOORE I D.Beam-on-springs modeling of jointed pipe culverts[J].Journal of Performance of Constructed Facilities,2016,30(2):1-9.
[15]TIAN Y H,CASSIDY M J,GAUDIN C.Advancing pipe-soil interaction models in calcareous sand[J].Applied Ocean Research,2010,32(3):284-297.
[16]HOLDER M S,CASSIDY M J.A plasticity model for predicting the vertical and lateral behaviour of pipelines in clay soils[J].Geotechnique,2010,60(4):247-263.
[17]HMADI K E,O′ROURKE M.Soil springs for buried pipeline axial motion[J].Journal of Geotechnical Engineering,1988,114(11):1 335-1 339.
[18]MATSUBARA K,HOSHIYA M.Soil spring constants of buried pipelines for seismic design[J].Journal of Engineering Mechanics,2000,126(1):76-83.
[19]钟阳,殷建华.弹性层状体的求解方法[M].北京:科学出版社,2007:142-150.(ZHONG Yang,YIN Jianhua.Solving method of elastic layered body[M].Beijing:Science Press,2007:142-150.(in Chinese))
[20]吴为义.盾构隧道周围地下管线的性状研究[博士学位论文][D].杭州:浙江大学,2008.(WU Weiyi.Study on mechanical behaviors of buried pipelines induced by shield tunnelling construction[Ph.D.Thesis][D].Hangzhou:Zhejiang University,2008.(in Chinese))
[21]邵羽.盾构双隧道施工对临近地埋管线的影响研究[博士学位论文][D].南宁:广西大学,2017.(SHAO Yu.Mechanism behaviors of existing buried pipelines due to twin shield tunnelling[Ph.D.Thesis][D].Nanning:Guangxi University,2017.(in Chinese))
[22]WHITE D J,RANDOLPH M F.Seabed characterisation and models for pipeline-soil interaction[J].International Journal of Offshore and Polar Engineering,2007,17(3):193-204.
[23]MYLONAKIS G,GAZETAS G.Settlement and additional internal forces of grouped piles in layered soil[J].Geotechnique,1998,48(1):55-72.
[24]RANDOLPH M F,WROTH C P.Analysis of deformation of vertically loaded piles[J].Journal of the Geotechnical Engineering Division,1978,104(12):1 465-1 488.
[25]方钱宝,马建林,喻渝,等.大断面黄土隧道围岩弹性抗力系数、变形模量与压缩模量试验研究[J].岩石力学与工程学报,2009,28(增2):3 932-3 937.(FANG Qianbao,MA Jianlin,YU Yu,et al.Experimental research on elastic resistant coefficient,deformation and compressive moduli of surrounding rock in large-section loess tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp.2):3 932-3 937.(in Chinese))
[26]HALDAR S,BASU D.Analysis of beams on heterogeneous and nonlinear soil[J].International Journal of Geomechanics,2016,16(4):04016004.