Site Response Of Non-Concentric Circular-Are Layered Alluvial Valleys & Canyons Excited By Incident Plane P Waves

Site response problem has become one of the two main wave propagation problems in earthquake engineering. The site response analysis mainly studies the effect of local site conditions with a certain characteristics on propagation of earthquake waves. Local site conditions can significantly amplify or reduce earthquake ground motion, and consequently effect the distribution of earthquake damage. In the nature, there are numerous kinds of local site conditions such as canyon, valley, hill, cavity, wedge and so on. A lot of investigations of earthquake damage indicate that special local site conditions can make important influences on surface ground motion, which also lead damage to overground and underground buildings more or less. Hence, the investigation of this kind of problem is much significative in both theory research and practical project.Many researches have focused on the object of alluvial valley and canyon. As two main kinds of local site in practical project, they are still an important and popular problem to be researched. On the base of some former research fruits, this thesis furtherly presents site response of non-concentric circular-arc layered alluvial valleys and canyons with non-concentric circular-arc layered cover excited by incident plane P waves.In this thesis, the way of Fourier-Bessel series expansion is adopted to gain the solution.It is convenient for solving the problem to use a cylindrical surface with a very large radius to approximate the surface of half-space. And, the incident wave, reflected waves and scattered waves are represented by the series of Fourier-Bessel expansion. In succession, it utilizes Graf's addition theorem to convert the coordinate. Then, according to boundary conditions, waveΦandΨcan be solved, and finally, the analysis solutions of displacement of surface ground can be gained.The results of site response influenced by such as the angle and frequency of incident waves, uneven depth of alluvial layer and canyon cover and so on are gained, and some qualitative conclusions are got.