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

本研究的目的是为了阐明大压力泥岩在地震作用下力学特性的变化。该试样由水泥与泥岩混合制成。为了研究施加压力随时间的影响，在三种情况下对试样施加压力；(1)无压力(2)胶结发育前(3)胶结发育后。在三轴压缩试验结果的基础上，研究了施加压力对材料力学特性的影响。与未施加压力的试件相比，施加较大压力的试件在胶结后的屈服轨迹有所扩大，并且屈服的形状取决于施加的压力。此外，在胶结发生前施加较大压力的试样的屈服轨迹与胶结发生后施加较大压力的试样的屈服轨迹呈现相似的膨胀形状。研究表明，在研究新近纪泥岩地层的力学特征时，应考虑地质工程的观点。

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.