Various field investigations of earthquake disaster cases have confirmed that earthquake-induced liquefaction is a main factor causing significant damage to dyke,research on seismic performances of dyke is thus of gre...Various field investigations of earthquake disaster cases have confirmed that earthquake-induced liquefaction is a main factor causing significant damage to dyke,research on seismic performances of dyke is thus of great importance.In this paper,seismic responses of dyke on liquefiable soils were investigated by means of dynamic centrifuge model tests and three-dimensional（3D） effective stress analysis method which is based on a multiple shear mechanism model and a liquefaction front.For the prototype scale centrifuge tests,sine wave input motions with peak accelerations 0.806 m/s2,1.790 m/s2 and 3.133 m/s2 of varied amplitudes were adopted to study the seismic performances of dyke on the saturated soil layer foundation with relative density of approximately 30%.Then,corresponding numerical simulations were conducted to investigate the distribution and variations of deformation,acceleration,excess pore-water pressure（EPWP）,and behaviors of shear dilatancy in the dyke and the liquefiable soil foundation.Moreover,detailed discussions and comparisons between numerical simulations and centrifuge tests were also presented.It is concluded that the computed results have a good agreement with the measured results by centrifuge tests.The physical and numerical models both indicate that the dyke hosted on liquefiable soils subjected to earthquake motions has exhibited larger settlement and lateral spread：the stronger the motion is,the larger the dyke deformation is.Compared to soils in the deep ground under the dyke and the free field,the EPWP ratio is much smaller in the shallow liquefiable soil beneath the dyke in spite of large deformation produced.For the same overburden depth soil from free site and the liquefiable foundation beneath dyke,the characteristics of effective stress path and stress-strain relations are different.All these results may be of theoretical and practical significance for seismic design of the dyke on liquefiable soils.展开更多
为定量评价一维土层地震反应分析方法的计算加速度反应谱和实测记录之间的差距,收集整理2418组DEEPSOIL、SHAKE2000、SOILQUAKE和SOILRESPONSE四种一维数值模拟方法的计算加速度反应谱,并以日本KiK-net强震台网的实测记录为基准,验证动...为定量评价一维土层地震反应分析方法的计算加速度反应谱和实测记录之间的差距,收集整理2418组DEEPSOIL、SHAKE2000、SOILQUAKE和SOILRESPONSE四种一维数值模拟方法的计算加速度反应谱,并以日本KiK-net强震台网的实测记录为基准,验证动态时间规整(Dynamic Time Warping,DTW)算法用于定量评价反应谱差距大小的适用性,对比分析不同场地类别和不同地表峰值加速度(Peak Ground Acceleration,PGA)区间的实测和计算加速度反应谱之间的DTW距离。结果表明:Ⅱ类场地下,PGA小于0.2g时,四种方法的平均DTW距离相差不大,PGA大于0.2g时SOILQUAKE方法的平均DTW距离较小;Ⅲ类场地下,PGA小于0.2g时DEEPSOIL方法的平均DTW距离较小,PGA大于0.2g时SOILRESPONSE方法的平均DTW距离较小;Ⅳ类场地下,PGA小于0.1g时DEEPSOIL方法的平均DTW距离较小,PGA大于0.1g时SOILRESPONSE方法的平均DTW距离较小;不同场地类别下,四种方法的DTW距离均随PGA的增大而增大,其中SOILRESPONSE在Ⅲ、Ⅳ类场地的DTW距离增速明显小于其他三种方法。DTW距离能准确有效地反映反应谱之间的差距,为一维土层地震反应分析方法的定量评价提供了新方法。展开更多
基金Financial supports provided by Science and Technological Fund of Anhui Province for Outstanding Youth(No.08040106830)National Natural Sciences Foundation of China(No.41172274)
文摘Various field investigations of earthquake disaster cases have confirmed that earthquake-induced liquefaction is a main factor causing significant damage to dyke,research on seismic performances of dyke is thus of great importance.In this paper,seismic responses of dyke on liquefiable soils were investigated by means of dynamic centrifuge model tests and three-dimensional（3D） effective stress analysis method which is based on a multiple shear mechanism model and a liquefaction front.For the prototype scale centrifuge tests,sine wave input motions with peak accelerations 0.806 m/s2,1.790 m/s2 and 3.133 m/s2 of varied amplitudes were adopted to study the seismic performances of dyke on the saturated soil layer foundation with relative density of approximately 30%.Then,corresponding numerical simulations were conducted to investigate the distribution and variations of deformation,acceleration,excess pore-water pressure（EPWP）,and behaviors of shear dilatancy in the dyke and the liquefiable soil foundation.Moreover,detailed discussions and comparisons between numerical simulations and centrifuge tests were also presented.It is concluded that the computed results have a good agreement with the measured results by centrifuge tests.The physical and numerical models both indicate that the dyke hosted on liquefiable soils subjected to earthquake motions has exhibited larger settlement and lateral spread：the stronger the motion is,the larger the dyke deformation is.Compared to soils in the deep ground under the dyke and the free field,the EPWP ratio is much smaller in the shallow liquefiable soil beneath the dyke in spite of large deformation produced.For the same overburden depth soil from free site and the liquefiable foundation beneath dyke,the characteristics of effective stress path and stress-strain relations are different.All these results may be of theoretical and practical significance for seismic design of the dyke on liquefiable soils.
文摘为定量评价一维土层地震反应分析方法的计算加速度反应谱和实测记录之间的差距,收集整理2418组DEEPSOIL、SHAKE2000、SOILQUAKE和SOILRESPONSE四种一维数值模拟方法的计算加速度反应谱,并以日本KiK-net强震台网的实测记录为基准,验证动态时间规整(Dynamic Time Warping,DTW)算法用于定量评价反应谱差距大小的适用性,对比分析不同场地类别和不同地表峰值加速度(Peak Ground Acceleration,PGA)区间的实测和计算加速度反应谱之间的DTW距离。结果表明:Ⅱ类场地下,PGA小于0.2g时,四种方法的平均DTW距离相差不大,PGA大于0.2g时SOILQUAKE方法的平均DTW距离较小;Ⅲ类场地下,PGA小于0.2g时DEEPSOIL方法的平均DTW距离较小,PGA大于0.2g时SOILRESPONSE方法的平均DTW距离较小;Ⅳ类场地下,PGA小于0.1g时DEEPSOIL方法的平均DTW距离较小,PGA大于0.1g时SOILRESPONSE方法的平均DTW距离较小;不同场地类别下,四种方法的DTW距离均随PGA的增大而增大,其中SOILRESPONSE在Ⅲ、Ⅳ类场地的DTW距离增速明显小于其他三种方法。DTW距离能准确有效地反映反应谱之间的差距,为一维土层地震反应分析方法的定量评价提供了新方法。
