The joint surface roughness coefficient (JRC) is an index that is defined by surface geometric characteristics and is related to the rock mass mechanical shear strength. Additionally, the rules of the rotation shear mechanism related to joints can be different from the linear shear mechanism and it has not been examined. Therefore, the present study has investigated the joint surface roughness problems in two steps. In first step, we use radial or rotational measurement method, as study procedure, by photogrammetric eva‎luation method in the presence of a rotational shear under the title of shear test and rotational or radial eva‎luation for finding the joint surface roughness coefficient of rocks. This study related to shear and rock joint fractures named rotational shear mechanism test, test pattern is showed by examining the type of mechanism and inventing laboratory device related to it. In the second step, determination of effective mechanism on the joint surface and execution related test is formed. Finally, to achieve the goal of the study, several tests were conducted on laboratory capacities that led to the invention of rotational shearing mechanism device to eva‎luate the rotational roughness and rotational resistance of the surface of rock joint. Also, in this study, by using the theoretical relations in other engineering topics based on the rotation shear mechanism and its extension to surface roughness of the rock joints relationships in order to provide a strong framework based on the rotation and twisting process. Consequently, all the parameters affecting the rotation process would be taken into account in the JRC calculation of surface of the rock joints based on the principles, correct and obvious concepts. For this purpose, Barton combs and photogrammetric methods with two types of linear and radial and rotational measurements were used and investigated to measure the surface of limestone rock joints from the Asmari Formation. The proposed roughness measurement method with radial meshing with a radius rate of 0.2 cm and the number of 20 sections has estimated the roughness coefficient values for each joint surface. However, the linear measurement method of joint surface roughness, which was formed by Barton combs and photogrammetric methods, eva‎luated the roughness of the rock joint surface with 0.5 cm and 0.25 cm mesh, respectively. Many other tests have been done to calculate the compressive strength parameters of the joint surface, unit weight of dry volume, residual friction angle and even to create a natural joint surface in the rock. Measurements of the joint surface are subjected to two stages before and after the rotary shear process test. The results obtained from the radial and rotational measurement methods show that this method provides a better capability and a more comprehensive eva‎luation than other measurement methods of measuring the surface of the rocks. The results obtained from the radial and rotational measurement methods show that this method provides a better capability and a more comprehensive eva‎luation than other measurement methods of measuring the surface of the rocks to give results provided by the proposed method show that the estimates are not dependent on the direction of roughness measurement. On the other hand, by performing back calculations based on the Barton-Bendis criterion on the laboratory data to estimate the JRC values from indirect methods, it was shown that this criterion cannot be generalized for the rotational shear process of rock joint surface problems and the calculations related to this field leads to unconventional results.

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