Temperature dependent viscous behavior on natural clay and the extension of a elasto-thermo-viscoplastic constitutive model

天然粘土在一维固结过程中的行为受以下因素的强烈影响。应变率和温度。先期固结压力是应变率和温度的函数。根据天然粘土的实验结果，讨论了天然粘土骨架的粘性和渗透性特征。建立了弹热粘塑性本构模型，模拟了天然粘土在不同应变率和不同温度下的一维行为。基于有效应力的有限元方法被应用于固结试验结果。1)对于所进行的所有试验，相对于与当时的应变率和温度对应的先期固结压力归一化的垂直有效应力与垂直应变之间的关系是唯一的。2)通过扩展Adachi an…建立了弹-热-粘塑性本构模型More d Oka的模型再现了天然粘土在不同应变率和温度下的行为。3)研究发现，所提出的弹热粘塑性本构模型能较好地再现天然贝蒂尔维尔粘土在不同应变率和温度下的一维粘性行为，并研究了屈服特性的重要性以及微结构对大阪上更新世海相粘土应力应变特性的影响。为了获得高质量的粘土样品，采用分块取样技术对更新世海相粘土进行了取样。用块取样技术获得的粘土样品比用管子取样技术获得的更新世粘土样品具有更高的质量。研究结果表明：1.大阪更新世海相粘土的屈服性质是各向异性的。2.更新世海相粘土具有明显的粘结连接结构，比扰动和重组样品具有更强的脆性、更高的抗压强度和更高的刚度。较少

The behavior of natural clays during one dimensional consolidation is strongly influenced by. strain rate as well as temperature. The preconsolidation pressure is a function of both strain rate and temperature. The viscous behavior of the natural clay skeleton as well as the characteristics of the permeability are discussed, based on the experimental results obtained on natural clay. Also, an elasto-thermo-viscoplastic constitutive model is developed to reproduce the one dimensional behavior of natural clays at different strain rates and temperatures. An effective stress based finite element method is applied to the experimental results of consolidation.1) For all the tests performed, the relationship between the vertical effective stress normalized with respect to the preconsolidation pressure corresponding to the strain rate and temperature at that time, and the vertical strain is unique.2) An elasto-thermo-viscoplastic constitutive model has been developed by extending the Adachi an … More d Oka's model to reproduce the behavior of natural clays at different strain rates and temperatures. The viseoplastic parameter introduced is found to depend at least as a first approximation on the temperature only through the temperature dependence of the preconsolidation pressure.3) It is found that the proposed elasto-thermo-viscoplastic constitutive model satisfactorily reproduce the one dimensional viscous behavior of the natural Berthierville clay at different strain rates and temperatures.An importance of yielding characteristic and an effect of the microstructure on stress-strain characteristics of Osaka Upper-Most Pleistocene marine clay are also studied. To get high quality clay samples, Pleistocene marine clays were sampled by block-sampling technique. Clay samples undertaken by the block-sampling technique are found to have higher quality than Pleistocene clay samples obtained by the tube : >sampling technique. The following conclusions are obtained from the present study : 1. Yielding properties of Osaka Pleistocene marine clays from the two sites are anisotropic. 2. The Pleistocene marine clay has a linkage structure with significant bonding, which induces more brittle behavior, higher compressive strength and higher stiffness than the disturbed and reconstituted samples. Less