Estimating Joint Normal and Shear Stiffness Coefficient Using Statistical Methods

In analyzing stability of geo-mechanical structures، considering the strength parameters of intact rock and discontinuity is of paramount importance. In jointed rocks، instable conditions are controlled in multiple manners by coefficient of discontinuity strength. The compressive strength of joint surface، roughness coefficient، deformation modules of rock mass and normal and shear stiffness coefficient are among the most important influential parameters in the behavior of discontinuities that often is estimated by experimental and in-situ tests. Among these parameters، estimating joint normal and shear stiffness coefficient، is expensive because it needs in-situ tests and use of huge and costly equipment، and there is a high probability of experimental and human error in it. In this study it has been tried to calculate some of the parameters of intact rocks and discontinuities that seem relevant to discontinuity normal and shear stiffness coefficient by using quantitative values. Therefore، the present data were gathered from the results of various experimental and in-situ tests and then were studied. Statistical analysis of single and multivariable of this data indicated that there is a considerable relationship between normal and shear stiffness coefficient with intact rock and discontinuity parameters in a way that estimating normal and shear stiffness coefficient from other parameters became possible.