Measurement of joint roughness coefficient by using profilograph and roughness ruler

Joint roughness coefficient (JRC) is the key parameter for the empirical estimation of joint shear strength by using the JRC-JCS (joint wall compressive strength) model. Because JRC has such characteristics as nonuniformity, anisotropy, and unhomogeneity, directional statistical measurement of JRC is the precondition for ensuring the reliability of the empirical estimation method. However, the directional statistical measurement of JRC is time-consuming. In order to present an ideal measurement method of JRC, new profilographs and roughness rulers were developed according to the properties of rock joint undulating shape based on the review of measurement methods of JRC. Operation methods of the profilographs and roughness rulers were also introduced. A case study shows that the instruments and operation methods produce an effective means for the statistical measurement of JRC.