Pilot studies on two dimensional wave propagation in rock masses
(1. School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798;
2. College of Architecture and Civil Engineering,
China University of Mining and Technology, Xuzhou 221008, China)
2. College of Architecture and Civil Engineering,
China University of Mining and Technology, Xuzhou 221008, China)
Abstract: Pilot studies on two dimensional(2-D) wave propagation through single joint or multiple parallel joints were comprehensively conducted, using a suitable data processing method. The possible factors influencing the transmission ratio in 2-D wave propagation under certain circumstances in rock masses were studied. It is found that in the process of 2-D wave propagation, for any radial line, the amount, the stiffness and the spacing of the joints influence the transmission ratio; by contrast, the transmission ratio at any point is independent of the radial distance from the center of wave source. It is also found that the transmission ratio for every grid-point along a single circle can present the transmission ratio for every grid-point after a certain quantity of joints. For the special radian direction(normal to the joints), it is concluded that the transmission ratio is dominated by the normal stiffness; while the influence of shear stiffness is negligible. The radius of the tunnel or borehole for the source wave does not affect the transmission ratio in 2-D wave propagation.
Key words: 2-D wave; transmission ratio; stiffness of joint; wave propagation; pilot study