Effect of High Pressure Loading and Unloading due to Diastrophism on Strength-deformation Characteristics of Mudstone

本研究的目的是阐明泥岩在经历了地壳运动后，其力学特性的变化。试件由水泥和泥岩混合制成。为了研究施加压力时时间的影响，在三种条件下对试样施加压力：（1）无压力（2）胶结作用发展之前（3）胶结作用发展之后。根据三轴压缩试验的结果，对施加压力引起的力学特性的变化进行了研究，结果表明，与未施加压力的试件相比，胶结后施加较大压力的试件的屈服轨迹扩大，屈服形状取决于施加的压力。此外，胶结作用发展前压力较大的试样的屈服轨迹与胶结作用发展后压力较大的试样的屈服轨迹呈相似形状的膨胀，研究表明，应考虑地质工程的观点来研究新近纪泥岩地基的力学特征。

The purpose of this study is to clarify the change in mechanical characteristics of mudstone which had a large pressure by diastrophism. The specimen was made by mixing cement with mudstone in slurry. To investigate the influence depending on the time when pressure is given, pressure was given to the specimen under three conditions ; (1) no pressure (2) before development of cementation (3) after development of cementation. The change of mechanical characteristics due to pressure to be applied was examined based on the results of the triaxial compression test.The yield locus in the specimen to which a large pressure was given after cementation expanded compared with that of the specimen to which no pressure was given, and the shape of the yield depended on the pressure to be applied. In addition, the yield locus of the specimen which had a large pressure before development of cementation showed an expansion in the similar shape as that of the specimen which had a pressure after development of cementation.From this study, it was revealed that the view of geological engineering should be taken into consideration to investigate mechanical characteristics of the mudstone ground of the Neogene period.