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到以下因素的强烈影响。应变速率和温度。预固结压力是应变速率和温度的函数。在对天然粘土进行试验的基础上，讨论了天然粘土骨架的黏性特性和渗透特性。此外，还建立了一个弹热粘塑性本构模型，以再现天然粘土在不同应变速率和温度下的一维行为。采用基于有效应力的有限元方法对固结试验结果进行了分析。1)在所有试验中，竖向有效应力相对于应变速率和温度对应的预固结压力归一化与竖向应变之间的关系是唯一的。2)通过扩展Adachi和…More d Oka的模型，建立了天然粘土在不同应变速率和温度下的弹热粘塑性本构模型。通过预固结压力的温度依赖性，发现引入的体塑性参数至少作为第一近似依赖于温度。3)所建立的弹热粘塑性本构模型较好地再现了天然Berthierville粘土在不同应变速率和温度下的一维粘性行为。研究了大阪上更新世海相粘土屈服特性的重要性以及微观结构对其应力-应变特性的影响。为了获得高质量的粘土样品，采用块体取样技术对更新世海相粘土进行了取样。用块状取样技术获得的粘土样品比用管状>取样技术获得的更新世粘土样品质量更高。本研究得出以下结论：1。两个地点大阪更新世海相粘土的屈服特性是各向异性的。2. 更新世海相粘土具有明显的连接结构，其脆性、抗压强度和刚度均高于扰动和重构后的样品。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