Research into Structure and Long-term Settlement of Osaka Bay Clay

大多数天然的沉积粘土随着年龄的增长变得更加坚硬和坚硬。同样，粘土与水泥的混合会随着时间的推移而变硬，这是由于化学(即火山灰)反应引起的织物粘结的发展。在这项研究中，这些天然和人工胶结的粘土被认为是与重组样品的类似行为的结构，考虑到这类粘土的力学行为明显较难压缩、更坚硬和更强。天然沉积粘土的力学行为不同于重组样品的可比行为，这是由于自然条件导致的地质时期的结构化，或者更确切地说，是由于织物中添加了化学键而导致的快速结构化的结果。本文在实验室中仔细研究了结构性粘土的力学行为，通过比较每个结构性粘土和重组样品在极小应变下的弹性剪切模数G，用Shibuya(2000)提出的亚稳性指数MI(G)来定量地评价粘土的结构。用Asaoka等人提出的超/次加载屈服面模型模拟了不排水剪切作用下的应力-应变和强度行为。(2000、2002)。

Most, natural, sedimentary clay becomes stiffer and stronger as it ages. Similarly, a clay mixed with cement hardens with time due to the development of fabric bonding caused by chemical (i.e., pozzolan) reaction. Such fabric bonding may also occur to some degree in natural ground with a high CO_3 content.In this research, these naturally and artificially cemented clays are regarded as "structured" to the comparable behavior of a reconstituted sample, bearing in mind that the mechanical behavior of such clays is noticeably less compressible, stiffer and stronger. The mechanical behavior of natural sedimentary clay clay is different from the comparable behavior of the reconstituted sample as the consequence of structuration induced over the geological period due to natural conditions or rather quickly due to the addition of chemical bonding in fabrics. In this paper, the mechanical behavior of such "structured" clays as highlighted by reduced compressibility, higher stiffness and higher strength was carefully examined in the laboratory.In comparing the elastic shear modulus at very small strains, G between each structured clay and the reconstituted sample, the clay structure was evaluated quantitatively by metastability index MI(G) proposed by Shibuya (2000). The stress-strain and strength behavior when subjected to undrained shear in compression was also simulated by the so-called super/subloading yield surface (SYS) Cam clay model proposed by Asaoka et al. (2000, 2002).