Estimation of In-Situ Normal Stiffness of Rock Mass Using Plate Load Test Data

Design of structures in rock mass require enough information on deformation and strength characteristics of rock mass. Numerical modeling techniques play an important role in analysis of the physical behavior of such structures. Such analyses involve various input parameters like material properties, boundary conditions, and applied loading. These input parameters need to be the best possible representation of the actual behavior of the structure on field. For rock mass, important parameters are elastic properties of intact rock, rock joints, their orientation, spacing and stiffness values. Reliable determination of normal and tangential stiffness values for a rock joint has always been a challenge. A lot of work has been done based on the laboratory tests to determine the normal and shear stiffness of rock joints. However, the present study utilizes the in-situ data collected from plate load tests to establish a correlation between modulus of deformation and normal stiffness.