Diffraction Of Cylindrical SH Waves Around A Cavity In Layered Half-space

In construction,the cylindrical waves generated by the explosion can affect theground motion near the tunnel and the dynamic stress concentration of the tunnel.So,itis necessery to compute the impact quantitatively.So far,the analysis about thisproblem is still limited to the even half-space.Hence,a new method was provided toanalysis the problem,verified and complemented the results of the layered elastichalf-space,and provided a new method for the further reserch.Diffraction of cylindrical SH waves around a cavity in layered elastic half-spaceis presented using indirect boundary element method (IBEM). The free-field responseunder a cylindrical SH wave is developed by expanding the cylindrical SH wave intoplane SH waves. The Green’s function of a uniformly distributed load acting on aninclined line in layered half-space is used for the calculation of response d ue tofictitious load on cavity boundary, and the fictitious load is determined by theboundary condition. The solution is obtained by the summation of the free-fieldresponse and the response due to the fictitious load. Finally, effects of the stiffnesscontrast between bedrock and soil layer, soil layer thickness, distance between thewave source to the cavity, incident frequency, etc., on the surface displacement andthe dynamic stress concentration factor (DSCF) of the cavity are studied byparametric analysis.In this paper,the results are proved right through comparising with the existingresults. The variation of the surface displacement and the stress concentration fator ofthe underground cavity arounded by cylindrical SH waves in layered half-space iscalculated and analysised.Some theoretical and actual conclusions are provided.