Scattering Of Cylindrical P And SV Waves By Underground, Circular Cavities

Along with the increasing severity of the problem of traffic and environment, it is an inevitable trend for modern city development to exploit and utilize the underground space cosmically. Scattering of cylindrical P and SV waves by the underground cavities can affect the ground motion near the cavities and the dynamic stress concentration of the cavities. So, the cylindrical waves generated by the explosion may affect the safety of the original underground cavities and it is necessary to compute the impact quantitatively .In this paper, the method of solution applied by Ohsaki (1973) will be adapted for underground and circular cavities. Basing on the characteristic of P,SV waves, the wave functions with unknown variables is first chosen to satisfy the wave equation, and scattered wave field is constructed by distributed line sources on the virtual source plane. The density of the virtual wave source can be gained by solving the equations which are derived by boundary conditions. Finally, the whole wave field can be achieved.The accuracy of the numerical result is checked up by the analytic solution and residual errors of boundary conditions with the increase of the truncation order. At the same time, the effects of some factors such as the frequency of the incident waves, the distance between the place where the cylindrical waves are excited and the centre of the cavities and the depth of the cavities, on the dynamic stress concentration factor on the walls of the cavities and also the ground motion are illustrated. And some useful conclusions are derived in this thesis.