小坡度海底土层地震液化诱发滑移分析方法
|
摘要
地震可使海底砂质、粉质土层液化并导致上部土层的滑移。基于有效应力有限元动力分析方法和Newmark刚性滑块理论,提出了一种计算海底小坡度(≤5o)土层地震液化引起侧向滑移的简化方法。该方法将波浪荷载简化为海底恒定的上覆压力和初始孔压,忽略了海水粘性对海底土层地震反应的影响,利用改进的Seed孔压模型进行动力分析和液化判别,用Newmark滑块理论计算了土层侧向滑移。通过算例和对比分析,研究了海水深度和土层坡度对侧向滑移的影响,表明该方法的有效性,可为近海工程场地地震地质灾害评价提供参考数据。
Landslide was caused by liquefaction in submarine sandy or silty slope due to earthquake. Based on effective stress finite element method and Newmark’s sliding block theory, simplified approach was developed for evaluating lateral slide displacements induced by liquefaction due to earthquake on submerged gentle slope (≤5o). Wave loads were simplified as constant pressure and initial excess pore pressure. Viscosity of seawater was ignored during dynamic analysis. Liquefaction analysis was conducted using improved Seed’s pore pressure model. According to Newmark’s model, accumulated lateral displacements of submerged slope were achieved during earthquake. By examples, effects of slope angle and sea depth were studied and the validity of the new analysis was confirmed. The method can be used to predict earthquake-induced submarine geological damages in offshore engineering fields.
Landslide was caused by liquefaction in submarine sandy or silty slope due to earthquake. Based on effective stress finite element method and Newmark’s sliding block theory, simplified approach was developed for evaluating lateral slide displacements induced by liquefaction due to earthquake on submerged gentle slope (≤5o). Wave loads were simplified as constant pressure and initial excess pore pressure. Viscosity of seawater was ignored during dynamic analysis. Liquefaction analysis was conducted using improved Seed’s pore pressure model. According to Newmark’s model, accumulated lateral displacements of submerged slope were achieved during earthquake. By examples, effects of slope angle and sea depth were studied and the validity of the new analysis was confirmed. The method can be used to predict earthquake-induced submarine geological damages in offshore engineering fields.
引文
[1]Seed R B,K O Cetin,R E S Moss,Kammerer A,Wu J,Pestana,J M,Riemer,M F Sancio,R B Bray,J D Kayen R E,Faris A.Recent advances in soil liquefaction engineering:a unified and consistent framework[A].White Paper for Keynote Presentation,26th Annual ASCE Los Angeles Geotechnical Spring Seminar[C]:California.[s.n.],2003.
[2]顾晓芸.粘质海底稳定性实例分析[J].工程地质学报,1996,4(1):32-38.
[3]叶银灿,陈锡土,宋连清,等.浙江北部岛屿海域土体稳定性研究[J].东海海洋,1996,14(1):1-18.
[4]冯秀丽,庄振业,林霖,等.现代黄河水下三角洲软土稳定性定量分析[J].海岸工程,2000,19(1):50-53.
[5]Azizian A,Popescu R.Backanalysis of the1929grand banks submarine slope failure[A].Proceedings of the54th Canadian Geotechnical Conference[C].[s.l.]:[s.n.],2001.808-815.
[6]Newmark N M.Effects of earthquakes on dams and embankments[J].Geotechnique,1965,15(2):139-159.
[7]石兆吉,郁寿松,丰万玲.土壤液化势的剪切波速判别法[J].岩土工程学报,1993,15(1):74-80.
[8]朱镜清.结构抗震分析原理[M].北京:地震出版社.2002.
[9]徐志英,沈珠江.地震液化的有效应力二维动力分析方法[J].华东水利学院学报,1981,9(3):1-14.
[10]Vaid Y P,Thomas J.Post liquefaction behavior of sand[J].Journal of Geotechnical Engineering,American Society of Civil Engineering,1995,121(2):163-173.
[11]刘汉龙,高玉峰,余湘娟.残余强度对地震液化后地面大位移的影响[J].岩石力学与工程学报,2001,20(增1):1163-1167.
[12]杨荣民,李安龙,曹立华,等.埕岛油田海底管道电缆路由勘察报告[R].No.CB20A—中心二号.山东:青岛海洋大学海洋地球科学学院,1997.
[13]Baziar M H,Dobry R,Alemi M,Evaluation of lateral ground deformation using sliding block model[A].Proceedings of the10th World Conference on Earthquake Engineering[C].Spain:Balkema A A Publishers,1992.1401-1406.
[2]顾晓芸.粘质海底稳定性实例分析[J].工程地质学报,1996,4(1):32-38.
[3]叶银灿,陈锡土,宋连清,等.浙江北部岛屿海域土体稳定性研究[J].东海海洋,1996,14(1):1-18.
[4]冯秀丽,庄振业,林霖,等.现代黄河水下三角洲软土稳定性定量分析[J].海岸工程,2000,19(1):50-53.
[5]Azizian A,Popescu R.Backanalysis of the1929grand banks submarine slope failure[A].Proceedings of the54th Canadian Geotechnical Conference[C].[s.l.]:[s.n.],2001.808-815.
[6]Newmark N M.Effects of earthquakes on dams and embankments[J].Geotechnique,1965,15(2):139-159.
[7]石兆吉,郁寿松,丰万玲.土壤液化势的剪切波速判别法[J].岩土工程学报,1993,15(1):74-80.
[8]朱镜清.结构抗震分析原理[M].北京:地震出版社.2002.
[9]徐志英,沈珠江.地震液化的有效应力二维动力分析方法[J].华东水利学院学报,1981,9(3):1-14.
[10]Vaid Y P,Thomas J.Post liquefaction behavior of sand[J].Journal of Geotechnical Engineering,American Society of Civil Engineering,1995,121(2):163-173.
[11]刘汉龙,高玉峰,余湘娟.残余强度对地震液化后地面大位移的影响[J].岩石力学与工程学报,2001,20(增1):1163-1167.
[12]杨荣民,李安龙,曹立华,等.埕岛油田海底管道电缆路由勘察报告[R].No.CB20A—中心二号.山东:青岛海洋大学海洋地球科学学院,1997.
[13]Baziar M H,Dobry R,Alemi M,Evaluation of lateral ground deformation using sliding block model[A].Proceedings of the10th World Conference on Earthquake Engineering[C].Spain:Balkema A A Publishers,1992.1401-1406.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心