关键词: 软弱结构面;平面P波;应力波理论;透射;反射;

Abstract: Weak structural planes are prone to be damaged under the dynamic load, which affects the safety of a project and the ground site.In this paper, based on a theoretical model of a weak structural plane, using the stress wave theory and considering the bonding and slip boundary conditions, the transmittance and reflection coefficients of the P wave injecting into the weak structural plane are deduced.And the theoretical results were compared and verified by the FEM numerical method.Then, the influence characteristics of P wave incidence angle, frequency and other factors on stress wave propagation are discussed.The research results show that the stress wave transmittance and reflection characteristics of bonding and sliding boundary are similar, but the stress wave loses energy in the sliding state.The weak structural plane has high-frequency filtering characteristics, so it is necessary to pay attention to the stability of the structural surface to low frequencies.When the equivalent friction angle of the weak structural plane increases, its shear deformation is more difficult to occur.The wave impedance ratio has a threshold on the stress wave transmission coefficient, and when it exceeds this threshold, the effect on the transmission coefficient is minimal.The stress wave transmittance and reflection coefficient shows a periodic fluctuation with the increase thickness of the filling material, and the period may be related to the wavelength of the P wave.The analysis of stress wave propagation characteristics is beneficial to determining the potential slippery weak structural plane in geotechnical engineering, and provides theoretical basis for seismic reinforcement and geotechnical blasting engineering.

Key words: weak structural plane; planar P wave; stress wave theory; transmission; reflection;