Development of a new measuring method of stress in discontinuous rock mass

摘要

Discontinuities usually exist in rocks and they have dominant effects on the mechanical behaviorrnof rocks. Therefore, it is necessary to grasp not only the mechanical characteristic of the discontinuousrnplanes in rocks but also the surface traction acting on the plane appropriately. Although severalrnresearches have focused on the mechanical characteristic , there exists no effective method to evaluaternin-situ traction on the discontinuities. Thus, a new stress sensor, STSG (Stress Transducer using StrainrnGauges), has been developed in the present study. The STSG consists of strain gauges placed in threernor more directions which is perpendicular to the discontinuous plane and which is parallel to thernshearing direction. In this study, the STSG was firstly used in a uniaxial cyclic loading tests on plasterrnspecimen to obtain elastic parameters of the specimen. Then, in order to check the applicability of thernSTSG to continuous and discontinuous material, the loading test was conducted using the specimensrnwithout any discontinuity and with a discontinuity.rnThe cyclic triaxial test was conducted on continuous specimen and the deviatoric stress measuredrnby STSG was 0.92-1.10 times of the controlled deviatoric stress. The stress close to a theoretical valuernwas measured by using STSG. In addition, the uniaxial cyclic loading test was conducted onrnspecimens including a discontinuity and heterogeneous stress distribution in the specimen wasrngrasped by using STSG.