Abstract To distinguish how the natural density of soil affects the seismic response of a soil slope, three large-scale shaking table tests are conducted on slopes of different densities under seismic excitations. The natural density of the homogeneous dense slope (HDS, case #1) is 1.65 g/cm3; that of the heterogeneous graded slope (HGS, case #2) increases from 1.35 g/cm3 to 1.65 g/cm3 with depth; that of the homogeneous loose slope (HLS, case #3) is 1.35 g/cm3. The failure processes, acceleration response laws, spectral characteristics, dynamic strain responses and shear stress-strain behaviours observed during the three tests are compared. The results show that the soil density distribution has a significant effect on the seismic response of a slope. The HGS and HLS fail suddenly under peak ground accelerations (PGAs) of 0.6 g and 0.5 g, respectively. The failure zone in the upper HLS is larger than that in the HGS. The acceleration amplification effect of the HDS is weak, while those of the HGS and HLS gradually increase with the PGA. The position and energy required to produce a nonlinear acceleration amplification factor effect are closely related to the natural density of the slope. The acceleration amplification factors of the HGS and HLS show nonlinear effects at 0.50 times and 0.357 times the slope height, respectively, and the corresponding PGAs are 0.4 g and 0.3 g. With an increasing natural density, the acceleration amplification factor decreases gradually, and more energy is required for the slope to fail under earthquake activity. The acceleration response law is related to the shape and amplitude of the peak in the fast Fourier transform (FFT) spectrum. The dominant frequency differences among the FFT spectra show that the lower the natural density of the slope is, the lower the location of damage in the slope. Combining the results of the peak micro-strain and shear stress-strain behaviour of the three slopes, the shear modulus of the HDS is the highest, and that of the HLS is the lowest.

中文翻译：

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不同自然密度土坡地震响应的大型振动台试验

摘要 为区分土体自然密度对土体边坡地震响应的影响，在地震激发下对不同密度的边坡进行了3次大型振动台试验。均质致密斜坡（HDS，案例#1）的自然密度为1.65 g/cm3；异质梯度坡度（HGS，案例#2）的坡度从 1.35 g/cm3 增加到 1.65 g/cm3；均匀松散斜率（HLS，案例#3）的值为 1.35 g/cm3。比较了三个试验中观察到的破坏过程、加速度响应规律、谱特性、动态应变响应和剪切应力-应变行为。结果表明，土体密度分布对边坡的地震响应有显着影响。HGS 和 HLS 在 0.6 g 和 0.5 g 的峰值地面加速度 (PGA) 下突然失效，分别。上部 HLS 中的故障区域大于 HGS 中的故障区域。HDS的加速放大效果较弱，而HGS和HLS的加速放大效果随着PGA的增加而逐渐增大。产生非线性加速度放大系数效应所需的位置和能量与斜坡的自然密度密切相关。HGS和HLS的加速度放大系数分别在0.50倍和0.357倍坡高处呈现非线性效应，对应的PGA分别为0.4 g和0.3 g。随着自然密度的增加，加速度放大系数逐渐减小，斜坡在地震活动下破坏需要更多的能量。加速度响应规律与快速傅里叶变换 (FFT) 频谱中峰值的形状和幅度有关。FFT 谱之间的主要频率差异表明，边坡的自然密度越低，边坡中的损伤位置越低。综合三个斜坡的峰值微应变和剪切应力应变行为的结果，HDS的剪切模量最高，HLS的剪切模量最低。