Microstructual Changes and Compressive Strength by means of Consolidation Methd,

本文研究的对象是粘性土固结过程中的微观结构变化、固结特性以及用一维固结法、Ko固结法和各向同性固结法计算的抗压强度。本研究选用五种再固结粘性土和近二十种原状粘性土为研究对象，探讨了土体抗剪强度各向异性与土体取向的相关性。对这些试样进行了一维固结、Ko固结和各向同性固结试验。对这些固结试样进行了无侧限压缩试验和固结不排水三轴压缩和拉伸试验。利用扫描电子显微镜观察了颗粒取向的变化，得到的主要结果如下：1。Ko固结试验的一维固结特征与趋势相似。但各向同性固结体应变以平均主应力表示比一维固结小，轴向应变与偏应力成正比.一方面，在一维固结和Ko固结中，随着固结压力的增大，各粘粒和/或颗粒的取向一般都趋于平行于水平面，另一方面，在各向同性固结中，各粘粒和/或颗粒的取向趋于随机结构.在相同孔隙比下，一维固结试样的无侧限抗压强度高于各向同性固结试样。强度的衰减与各向同性固结压力成正比.阐明了孔隙比、孔隙取向与无侧限抗压强度或渗透率的关系。

The objects in this study are microstructual changes in consolidation process, the characteristics of consolidation and compressive strength by means of one-dimentional, Ko, and isotropic consolidation methods, in cohesive soils. Furthermore the correlations of shear strength anisotropy and orientation of peds are investigated.Five kinds of reconsolidated clayey soiles and approximately twenty kinds of undisturbed cohesive soils were used in this study. Theses samples were carried out one-dimentional, Ko, and isotropic consolidation tests. Unconfined compression test and consolidated undrained triaxial compression and extension tests were performed on these consolidated samples. A scanning electron microscope were used to observe the changes in particle orientation.The main results obtained are as follows:1. The characteristics in one-dimentional consolidation of Ko consolidation test are similar to tendancy. But the volumetric strain of isotropic consolidation in terms of the mean principal stress is smallev than one-dimentional consolidation, and the axial strain is proportional to the deviator stres.2. On the one hand the orientation of each clay particle and / or ped in one-dimentional and Ko consolidation generally becomes parallel to horizontal plane with the increase in consolidation pressure, the other hand in isotropic consolidation becoms to ramdom structure.3. In same void ratio, unconfined compressive strength in one-dimentional consolidation specimen is higher than isotropic consolidation specimen. The differen of strength decreases in proportinal to isotropic consolidation pressure.4. It is illustrated that the relationship between the void ration, orientafion of peds, and unconfined compressive strength or permeability.