A constitutive model for clays and plastic silts in plane-strain earthquake engineering applications
A constitutive model for clays and plastic silts in plane-strain earthquake engineering applications
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DOI：
10.1016/j.soildyn.2019.105832
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发表时间：
2019-12
影响因子：
4
通讯作者：
R. Boulanger;K. Ziotopoulou
中科院分区：
文献类型：
--
作者：
R. Boulanger;K. Ziotopoulou
本文提出了一种在岩土地震工程应用中用于表示粘土和塑性粉土的塑性模型，而不是纯粹的非塑性粉土或砂土。PM4Silt模型建立在应力比控制的、基于临界状态的边界面塑性PM4Sand模型的框架上，并被编码为用户定义的材料，用于程序FLAC。该模型提供了合理的近似单调不排水剪切强度，循环不排水剪切强度，剪切模量降低和滞回阻尼响应。该模型不包括上限，因此不适用于模拟固结或再固结沉降（即，体积应变）或强度随固结应力或地震荷载历史的演化。主要输入参数是不排水抗剪强度比（或不排水抗剪强度）、剪切模量系数和收缩率参数。所有辅助输入参数均根据默认校准指定默认值，但在根据高级实验室测试数据进行校准或执行灵敏度研究时可进行调整。校准过程中描述和说明的校准为三种不同的正常固结，细颗粒土的塑性指数范围从4到20。该模型提供了合理的近似行为，重要的许多地震工程应用，并相对容易校准。
A plasticity model for representing clays and plastic silts, as opposed to purely nonplastic silts or sand, in geotechnical earthquake engineering applications is presented. The PM4Silt model builds on the framework of the stress-ratio controlled, critical state based, bounding surface plasticity PM4Sand model, and is coded as a user defined material for use with the program FLAC. The model was developed to provide reasonable approximations of monotonic undrained shear strength, cyclic undrained shear strength, and shear modulus reduction and hysteretic damping responses. The model does not include a cap, and therefore is not suited for simulating consolidation or reconsolidation settlements (i.e., volumetric strains) or strength evolution with consolidation stress or seismic loading history. The primary input parameters are the undrained shear strength ratio (or undrained shear strength), the shear modulus coefficient, and the contraction rate parameter. All secondary input parameters are assigned default values based on a default calibration, but may be adjusted when calibrating against advanced laboratory test data or performing sensitivity studies. The calibration process is described and illustrated by calibrations for three different normally consolidated, fine-grained soils with plasticity indices ranging from 4 to 20. The model is shown to provide reasonable approximations of behaviors important to many earthquake-engineering applications and to be relatively easy to calibrate.