地震作用下地表侧移量简化计算方法研究
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摘要
地表侧移由地震引起的饱和砂土液化诱发,地表沿着缓坡或自由面产生移动。依据场地的液化特性,利用Newmark滑块计算法对由液化引起的地表侧移进行计算。利用非线性场地响应分析,根据场地土层特性,构建一维场地响应模型。将已有的基岩地震波作为场地输入,计算可液化土的液化时间点,获得液化土下的地震波。利用标准贯入试验计算可液化土的残余剪切强度,并赋予非液化土摩尔库伦参数,利用极限平衡分析求得场地的屈服加速度。将屈服加速度和考虑液化时间后的可液化土层下的地震波作为输入参数,采用Newmark滑块法计算场地的侧移。将该方法应用于台湾集集地震侧移算例中,依据钻孔资料计算得到可液化土体残余强度为7.08 kPa。将反卷积分析得到的强震记录作为输入地震波,设置各土层的滞回曲线和阻尼比曲线,对地下水位下土层设置孔隙水压模型,对场地进行非线性响应分析并获得所需地震波。将场地简化为二维的SLIDE 5.0模型计算屈服加速度。经Newmark滑块法计算,所得侧移预测值与地震后现场观测值(1.62 m)接近,结果表明考虑液化特征的侧移计算方法可用于实际工程中的侧移预测。
The paper is intended to provide a Newmark sliding block method based upon the special features of the liquefaction on the condition that the ground surface movement is going on along the slope towards the free face in case the liquefaction were triggered.In such a situation,it would be necessary to conduct a nonlinear site analysis first of all based on the spot investigation with the 1-D model analyzed on account of the particular features of the earthquake induced liquefaction.What is more,since the movement or displacement recorded at the bedrock can be taken as the input displacement of the site,it is necessary to find out the triggering time of the liquefaction through the nonlinear analysis.On the other hand,the movement beneath the liquefied soil should also be calculated based on the site response analysis and the triggering time of liquefaction,the undrain shear strength of the liquefiable soil by the SPT blow accounts,as well as the parameters of the non-liquefiable soil in accordance with the MohrCoulomb criteria.Besides,it is also of great need to do the limit equilibrium analysis to work out the yield acceleration of the site.So far as the Newmark sliding block analysis is concerned,it has to be done by using the yield acceleration from the limit equilibrium analysis and the displacements beneath the liquefied soil,also which has to be modified on the basis of triggering time of liquefaction.To be more specific,here we would like to quote a sample case that has been adopted in the historical case of Chi-Chi earthquake(that took place in Nantou County,Taiwan).The residual shear strength of the liquefiable soil has been calculated as7.08 k Pa based on the site investigation.The strong movement processed with the deconvolution analysis has been taken as the input motion,with the shear modulus reduction curves and damping ratio curves being assigned to the soils on site and the soil below the water level with the model as the pore water pressure.And,then,a nonlinear site analysis of the site has also been done to gain the input motion,or movement,with the site being simplified as a 2-D model in SLIDE to obtain the yield acceleration.The result of the calculation,as predicted with the proposed Newmark sliding block method,proves to be consistent with the observed lateral spreading of 1.62 m.Thus,the method for predicting the liquefaction specific features proves to be practicable and applicable for predicting the lateral extension in the engineering practice.
The paper is intended to provide a Newmark sliding block method based upon the special features of the liquefaction on the condition that the ground surface movement is going on along the slope towards the free face in case the liquefaction were triggered.In such a situation,it would be necessary to conduct a nonlinear site analysis first of all based on the spot investigation with the 1-D model analyzed on account of the particular features of the earthquake induced liquefaction.What is more,since the movement or displacement recorded at the bedrock can be taken as the input displacement of the site,it is necessary to find out the triggering time of the liquefaction through the nonlinear analysis.On the other hand,the movement beneath the liquefied soil should also be calculated based on the site response analysis and the triggering time of liquefaction,the undrain shear strength of the liquefiable soil by the SPT blow accounts,as well as the parameters of the non-liquefiable soil in accordance with the MohrCoulomb criteria.Besides,it is also of great need to do the limit equilibrium analysis to work out the yield acceleration of the site.So far as the Newmark sliding block analysis is concerned,it has to be done by using the yield acceleration from the limit equilibrium analysis and the displacements beneath the liquefied soil,also which has to be modified on the basis of triggering time of liquefaction.To be more specific,here we would like to quote a sample case that has been adopted in the historical case of Chi-Chi earthquake(that took place in Nantou County,Taiwan).The residual shear strength of the liquefiable soil has been calculated as7.08 k Pa based on the site investigation.The strong movement processed with the deconvolution analysis has been taken as the input motion,with the shear modulus reduction curves and damping ratio curves being assigned to the soils on site and the soil below the water level with the model as the pore water pressure.And,then,a nonlinear site analysis of the site has also been done to gain the input motion,or movement,with the site being simplified as a 2-D model in SLIDE to obtain the yield acceleration.The result of the calculation,as predicted with the proposed Newmark sliding block method,proves to be consistent with the observed lateral spreading of 1.62 m.Thus,the method for predicting the liquefaction specific features proves to be practicable and applicable for predicting the lateral extension in the engineering practice.
引文
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[2]YOUD,T L,CORBETT M H,STEVEN F B.Revised multilinear regression equations for prediction of lateral spread displacement[J].Journal of Geotechnical and Geoenvironmental Engineering,2002,128(12):1007-1017.
[3]ZHANG J,ZHAO J X.Empirical models for estimating liquefaction induced lateral spread displacement[J].Soil Dynamics and Earthquake Engineering,2005,25(6):439-450.
[4]FARIS A T,SEED R B,KAYEN R E,et al.A semi-empirical model for the estimation of maximum horizontal displacement due to liquefaction-induced lateral spreading[C]//Proc of the 8th US Conference on Earthquake Engineering,Vol.3.Oakland,CA:Earthquake Engineering Research Institute,2006:1583-1584.
[5]KEVIN W F,STEVEN L K.Procedure for the empirical evaluation of lateral spread displacement hazard curves[J].Journal of Geotechnical and Geoenvironmental Engineering,2014,140(1):110-120.
[6]SHAO Guangbiao(邵广彪),FENG Qimin(冯启民),WANGHuajuan(王华娟).A method for numerical analysis of earthquake induced lateral displacements of submerged gentle slope[J].Rock and Soil Mechanics(岩土力学),2006,27(9):1601-1606.
[7]SHAO Guangbiao(邵广彪),WANG Huajuan(王华娟).A method for numerical analysis of seismic liquefaction induced large deformation of sloping soil layer[J].Rock and Soil Mechanics(岩土力学),2006,27(S):1027-1031.
[8]TONG Liyuan(童立元),WANG Bin(王斌),LIU Yihuai(刘义怀).3D numerical simulation of large ground displacement caused by seismic liquefaction[J].Rock and Soil Mechanics(岩土力学),2008,29(8):2226-2230.
[9]ZOU Yan(邹炎),JING Liping(景立平),CUI Jie(崔杰).Factor analysis based on numerical simulation of liquefiable site's seismic responses[J].Journal of Disaster Prevention and Mitigation Engineering(防灾减灾工程学报),2015,35(2):242-248.
[10]PHILLIPS C,HASHASH Y M,OLSON S M,et al.Significance of small strain damping and dilation parameters in numerical modeling of free-field lateral spreading centrifuge tests[J].Soil Dynamics and Earthquake Engineering,2012,42:161-176.
[11]KAMAI R,BOULANGER R W.Simulations of a centrifuge test with lateral spreading and void redistribution effects[J].Journal of Geotechnical and Geoenvironmental Engineering,2012,139(8):1250-1261.
[12]HOWELL R,RATHJE E M,BOULANGER R W.Evaluation of simulation models of lateral spread sites treated with prefabricated vertical drains[J].Journal of Geotechnical and Geoenvironmental Engineering,2015,141(1):04014076.
[13]GHASEMI-FARE O,PAK A.Prediction of lateral spreading displacement on gently sloping liquefiable ground[C]//Geotechnical Frontiers 2017.Red Hook,NY:Curran Associates,Inc.,2017:267-276.
[14]NEWMARK N M.Effects of earthquakes on dams and embankments[J].Géotechnique,1965,15(2):139-160.
[15]RATHJE E M,BRAY J D.Nonlinear coupled seismic sliding analysis of earth structures[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(11):1002-1014.
[16]SCOTT M O,CORA I J.Analyzing liquefaction-induced lateral spreads using strength ratios[J].Journal of Geotechnical and Geoenvironmental Engineering,2008,134(8):1035-1049.
[17]JONATHAN D B,THALEIA T.Simplified procedure for estimating earthquake-induced deviatoric slope displacements[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(4):381-392.
[18]RATHJE E M,SAYGILI G.Estimating fully probabilistic seismic sliding displacements of slopes from a pseudo-probabilistic approach[J].Journal of Geotechnical and Geoenvironmental Engineering,2011,137(3):208-217.
[19]MAKDISI A J.The applicability of sliding block analyses for the prediction of lateral spreading displacements[D].Washington:University of Washington,2016.
[20]SHARP M K,DOBRY R.Sliding block analysis of lateral spreading based on centrifuge results[J].International Journal of Physical Modelling in Geotechnics,2002,2(2):13-32.
[21]SHARP M K,DOBRY R,PHILLIPS R.CPT-based evaluation of liquefaction and lateral spreading in centrifuge[J].Journal of Geotechnical and Geoenvironmental Engineering,2010,136(10):1334-1346.
[22]BETHAPUDI R.Liquefaction induced lateral spreading in largescale shake testing[D].Buffalo:State University of New York at Buffalo,2008.
[23]LI Chengcheng(李程程),CAO Zhenzhong(曹振中),LI Ruishan(李瑞山).Assessment criterion for level of liquefaction-induced lateral spread and its reliability analysis[J].Chinese Journal of Geotechnical Engineering(岩土工程学报),2016,38(9):1668-1677.
[24]SCHNABEL P,LYSMER J,SEED H B.SHAKE:a computer program for conducting equivalent linear seismic response analysis of horizontally layered soil deposits,Report No.UCB/EERC[R].Berkeley:Earthquake Engineering,Research Center,University of California in Berkeley,1972.
[25]MATASOVIC N,ORDONEZ G A.D-MOD 2000-a computer program package for seismic response analysis of horizontally layered soil deposits,earthfill dams,and solid waste landfills,user's manual[M].Washington:Geomotions,LLC,2007.
[26]KONDNER R L,ZELASKO J S.A hyperbolic stress-strain formulation of sands[C]//Proceedings of the 2nd Panameircan Conference on Soil Mechanics and Foundation Engineering.Sao Paulo,Brazil:Brazilian Association of Soil Mechanics,1963:289-324.
[27]CHU A,STEWART M,CHU D B,et al.Liquefaction-induced lateral spreading in near-fault regions during the 1999 Chi-Chi,Taiwan earthquake[J].Journal of Geotechnical and Geoenvironmental Engineering,2006,132(12):1549-1565.
[28]Electric Power Research Institute(EPRI).Guidelines for site specific ground motions[S].Palo Alto,CA:Electric Power Research Institute,1993.
[29]SEED H B,WONG R T,IDRISS I M,et al.Soil moduli and damping factors for dynamic response analyses[J].Journal of Geotechnical Engineering,1986,112(11):1016-1032.
[30]LU Shasha(路沙沙),MA Fenghai(麻凤海),LU Yanyan(路艳艳).Simulated testing study on the seismic dynamic response from the subway tunnel[J].Journal of Safety and Environment(安全与环境学报),2016,16(5):93-98.
[31]CUI Tiejun(崔铁军),LI Shasha(李莎莎),WANG Laigui(王来贵).Analysis of the collapse form and process of the hollow-out high-rise buildings under the earthquake shaking load[J].Journal of Safety and Environment(安全与环境学报),2018,18(1):90-94.
[2]YOUD,T L,CORBETT M H,STEVEN F B.Revised multilinear regression equations for prediction of lateral spread displacement[J].Journal of Geotechnical and Geoenvironmental Engineering,2002,128(12):1007-1017.
[3]ZHANG J,ZHAO J X.Empirical models for estimating liquefaction induced lateral spread displacement[J].Soil Dynamics and Earthquake Engineering,2005,25(6):439-450.
[4]FARIS A T,SEED R B,KAYEN R E,et al.A semi-empirical model for the estimation of maximum horizontal displacement due to liquefaction-induced lateral spreading[C]//Proc of the 8th US Conference on Earthquake Engineering,Vol.3.Oakland,CA:Earthquake Engineering Research Institute,2006:1583-1584.
[5]KEVIN W F,STEVEN L K.Procedure for the empirical evaluation of lateral spread displacement hazard curves[J].Journal of Geotechnical and Geoenvironmental Engineering,2014,140(1):110-120.
[6]SHAO Guangbiao(邵广彪),FENG Qimin(冯启民),WANGHuajuan(王华娟).A method for numerical analysis of earthquake induced lateral displacements of submerged gentle slope[J].Rock and Soil Mechanics(岩土力学),2006,27(9):1601-1606.
[7]SHAO Guangbiao(邵广彪),WANG Huajuan(王华娟).A method for numerical analysis of seismic liquefaction induced large deformation of sloping soil layer[J].Rock and Soil Mechanics(岩土力学),2006,27(S):1027-1031.
[8]TONG Liyuan(童立元),WANG Bin(王斌),LIU Yihuai(刘义怀).3D numerical simulation of large ground displacement caused by seismic liquefaction[J].Rock and Soil Mechanics(岩土力学),2008,29(8):2226-2230.
[9]ZOU Yan(邹炎),JING Liping(景立平),CUI Jie(崔杰).Factor analysis based on numerical simulation of liquefiable site's seismic responses[J].Journal of Disaster Prevention and Mitigation Engineering(防灾减灾工程学报),2015,35(2):242-248.
[10]PHILLIPS C,HASHASH Y M,OLSON S M,et al.Significance of small strain damping and dilation parameters in numerical modeling of free-field lateral spreading centrifuge tests[J].Soil Dynamics and Earthquake Engineering,2012,42:161-176.
[11]KAMAI R,BOULANGER R W.Simulations of a centrifuge test with lateral spreading and void redistribution effects[J].Journal of Geotechnical and Geoenvironmental Engineering,2012,139(8):1250-1261.
[12]HOWELL R,RATHJE E M,BOULANGER R W.Evaluation of simulation models of lateral spread sites treated with prefabricated vertical drains[J].Journal of Geotechnical and Geoenvironmental Engineering,2015,141(1):04014076.
[13]GHASEMI-FARE O,PAK A.Prediction of lateral spreading displacement on gently sloping liquefiable ground[C]//Geotechnical Frontiers 2017.Red Hook,NY:Curran Associates,Inc.,2017:267-276.
[14]NEWMARK N M.Effects of earthquakes on dams and embankments[J].Géotechnique,1965,15(2):139-160.
[15]RATHJE E M,BRAY J D.Nonlinear coupled seismic sliding analysis of earth structures[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(11):1002-1014.
[16]SCOTT M O,CORA I J.Analyzing liquefaction-induced lateral spreads using strength ratios[J].Journal of Geotechnical and Geoenvironmental Engineering,2008,134(8):1035-1049.
[17]JONATHAN D B,THALEIA T.Simplified procedure for estimating earthquake-induced deviatoric slope displacements[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(4):381-392.
[18]RATHJE E M,SAYGILI G.Estimating fully probabilistic seismic sliding displacements of slopes from a pseudo-probabilistic approach[J].Journal of Geotechnical and Geoenvironmental Engineering,2011,137(3):208-217.
[19]MAKDISI A J.The applicability of sliding block analyses for the prediction of lateral spreading displacements[D].Washington:University of Washington,2016.
[20]SHARP M K,DOBRY R.Sliding block analysis of lateral spreading based on centrifuge results[J].International Journal of Physical Modelling in Geotechnics,2002,2(2):13-32.
[21]SHARP M K,DOBRY R,PHILLIPS R.CPT-based evaluation of liquefaction and lateral spreading in centrifuge[J].Journal of Geotechnical and Geoenvironmental Engineering,2010,136(10):1334-1346.
[22]BETHAPUDI R.Liquefaction induced lateral spreading in largescale shake testing[D].Buffalo:State University of New York at Buffalo,2008.
[23]LI Chengcheng(李程程),CAO Zhenzhong(曹振中),LI Ruishan(李瑞山).Assessment criterion for level of liquefaction-induced lateral spread and its reliability analysis[J].Chinese Journal of Geotechnical Engineering(岩土工程学报),2016,38(9):1668-1677.
[24]SCHNABEL P,LYSMER J,SEED H B.SHAKE:a computer program for conducting equivalent linear seismic response analysis of horizontally layered soil deposits,Report No.UCB/EERC[R].Berkeley:Earthquake Engineering,Research Center,University of California in Berkeley,1972.
[25]MATASOVIC N,ORDONEZ G A.D-MOD 2000-a computer program package for seismic response analysis of horizontally layered soil deposits,earthfill dams,and solid waste landfills,user's manual[M].Washington:Geomotions,LLC,2007.
[26]KONDNER R L,ZELASKO J S.A hyperbolic stress-strain formulation of sands[C]//Proceedings of the 2nd Panameircan Conference on Soil Mechanics and Foundation Engineering.Sao Paulo,Brazil:Brazilian Association of Soil Mechanics,1963:289-324.
[27]CHU A,STEWART M,CHU D B,et al.Liquefaction-induced lateral spreading in near-fault regions during the 1999 Chi-Chi,Taiwan earthquake[J].Journal of Geotechnical and Geoenvironmental Engineering,2006,132(12):1549-1565.
[28]Electric Power Research Institute(EPRI).Guidelines for site specific ground motions[S].Palo Alto,CA:Electric Power Research Institute,1993.
[29]SEED H B,WONG R T,IDRISS I M,et al.Soil moduli and damping factors for dynamic response analyses[J].Journal of Geotechnical Engineering,1986,112(11):1016-1032.
[30]LU Shasha(路沙沙),MA Fenghai(麻凤海),LU Yanyan(路艳艳).Simulated testing study on the seismic dynamic response from the subway tunnel[J].Journal of Safety and Environment(安全与环境学报),2016,16(5):93-98.
[31]CUI Tiejun(崔铁军),LI Shasha(李莎莎),WANG Laigui(王来贵).Analysis of the collapse form and process of the hollow-out high-rise buildings under the earthquake shaking load[J].Journal of Safety and Environment(安全与环境学报),2018,18(1):90-94.