In dynamic geotechnical problems, soils are often subjected to a combination of sustained static and fast cyclic loading. Under such loading conditions, saturated and normally consolidated clays generally experience a build‐up of excess pore water pressure along with a degradation of stiffness and strength. If the strength of the soil falls below the static stress demand, a self‐driven failure is triggered. In this paper, a constitutive model is presented for the analysis of such problems, based on a general multisurface plasticity framework. The hardening behavior, the initial arrangement of the surfaces, and the nonassociated volumetric flow rule are defined to capture important aspects of cyclic clay behavior. This includes nonlinear hysteretic stress‐strain behavior, the effect of anisotropic consolidation, and the generation of excess pore water pressure during undrained cyclic loading along with a degradation of stiffness and strength. The model requires nine independent parameters, which can be derived from standard laboratory tests. A customized experimental program has been performed to validate the model performance. The model predictions show a good agreement with test results from monotonic and cyclic undrained triaxial tests, in particular with respect to the strain‐softening response and the number of loading cycles to failure. A procedure for a general stress‐space implicit numerical implementation for undrained, total stress‐based finite element analyses is presented, including the derivation of the consistent tangent operator. Finally, a simulation of the seismic response of a submarine slope is shown to illustrate a possible application of the presented model.

中文翻译：

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静态和不排水循环荷载作用下黏土特性的多表面运动硬化模型

在动态岩土问题中，土壤通常承受持续的静态荷载和快速的循环荷载。在这样的载荷条件下，饱和和正常固结的粘土通常会经历过高的孔隙水压力，同时会降低刚度和强度。如果土壤强度低于静态应力需求，则会触发自驱动破坏。本文基于一般的多表面可塑性框架，提出了用于分析此类问题的本构模型。定义了硬化行为，表面的初始排列以及不相关的体积流规则，以捕获循环黏土行为的重要方面。这包括非线性滞后应力-应变行为，各向异性固结的影响，以及在不排水的循环荷载作用下产生的多余孔隙水压力，以及刚度和强度的下降。该模型需要九个独立的参数，这些参数可以从标准实验室测试中得出。已执行定制的实验程序以验证模型性能。模型预测表明与单调和循环不排水三轴试验的试验结果吻合良好，特别是在应变软化响应和破坏荷载循环次数方面。提出了一种不排水，基于总应力的有限元分析的通用应力空间隐式数值实现方法，其中包括一致切线算符的推导。最后，