A numerical model based on the finite element framework was developed to predict the seismic response of saturated sand under free-field conditions. The finite element framework used a non-linear coupled hypoplastic model based on the u-p formulation to simulate the behaviour of the saturated sand. The u-p coupled constitutive model was implemented as a user-defined routine in commercial ABAQUS explicit 6.14. Results of centrifuge experiments simulating seismic site response of a layered saturated sand system were used to validate the numerical results. The centrifuge test consisted of a three-layered saturated sand system subjected to one-dimensional seismic shaking at the base. The test set-up was equipped with accelerometers, pore pressure transducers, and LVDTs at various levels. Most of the constitutive models used to date for predicting the seismic response of saturated sands have underestimated volumetric strains even after choosing material parameters subjected to rigorous calibration measures. The hypoplastic model with intergranular strains calibrated against monotonic triaxial test results was able to effectively capture the volumetric strains, reasons for which are discussed in this paper. The comparison of the numerical results to centrifuge test data illustrates the capabilities of the developed u-p hypoplastic formulation to perform pore fluid analysis of saturated sand in ABAQUS explicit, which inherently lacks this feature.

建立了基于有限元框架的数值模型来预测自由场条件下饱和砂土的地震响应。有限元框架使用基于 up 公式的非线性耦合亚塑性模型来模拟饱和砂的行为。上耦合本构模型作为用户定义的程序在商业 ABAQUS 显式 6.14 中实现。模拟分层饱和砂岩系统地震现场响应的离心机实验结果用于验证数值结果。离心机试验包括一个三层饱和砂系统，在底部进行一维地震震动。测试装置配备了不同级别的加速度计、孔隙压力传感器和 LVDT。迄今为止，大多数用于预测饱和砂岩地震响应的本构模型即使在选择经过严格校准措施的材料参数后也低估了体积应变。具有根据单调三轴试验结果校准的晶间应变的亚塑性模型能够有效地捕获体积应变，本文讨论了其原因。数值结果与离心机测试数据的比较说明了开发的亚塑性公式在 ABAQUS 显式中对饱和砂进行孔隙流体分析的能力，而 ABAQUS 显式本身就缺乏此功能。具有根据单调三轴试验结果校准的晶间应变的亚塑性模型能够有效地捕获体积应变，本文讨论了其原因。数值结果与离心机测试数据的比较说明了开发的亚塑性公式在 ABAQUS 显式中对饱和砂进行孔隙流体分析的能力，而 ABAQUS 显式本身就缺乏此功能。具有根据单调三轴试验结果校准的晶间应变的亚塑性模型能够有效地捕获体积应变，本文讨论了其原因。数值结果与离心机测试数据的比较说明了开发的亚塑性公式在 ABAQUS 显式中对饱和砂进行孔隙流体分析的能力，而 ABAQUS 显式本身就缺乏此功能。