Feasibility study on contact stiffness acquisition by hammering tests and numerical back-analysis for parallel structural plane of rock mass

The contact stiffness acquisition method for the relatively uniform parallel structure of rock mass by hammering tests and numerical back-analysis is proposed. And the contact stiffness of structural plane is described based on the linear contact hypothesis. The vibration sensors are laid at both sides of the structural surface, and shock is produced by hammer in the distance. The time consumption of longitudinal waves penetrating the structural planes can be calculated by the wave arrival time of the sensors, the direction of which is perpendicular to the structural plane. The time consumption of transverse waves penetrating the structural planes can be observed by the wave arrival time of the sensors, the direction of which is parallel to the structural plane. The normal and tangential contact stiffnesses need to constantly be adjusted in the numerical model by means of numerical back-analysis. The normal and tangential contact stiffnesses are obtained when the time consumption of hammering tests is equal to the numerical calculation. The feasibility of the contact stiffness acquisition method is demonstrated through theoretical and numerical analysis. The results show that the time consumption of longitudinal waves penetrating the structural planes is only controlled by the normal contact stiffness, and that of transverse waves penetrating the structural planes is only controlled by the tangential contact stiffness. The feasibility and consistency of the contact stiffness acquisition method is validated by the hammering tests and numerical analysis of granite rocks.