Transient Numerical Simulation Of Semicircular Arch And Underground Hole By P-wave

In actual projects, scattering and diffraction of earthquake waves by the large underground structures with hole can not only affect the ground motion near the opening structures, but also it can affect the buildings on the ground nearby. There fore, it is very important to solve this kind of problem for theory and engineering application. The underground circular hole has big influence on the surface displacement can greatly amplify the surface displacement which is brought by the incident plane P-wave. In this paper the displacement, the stress, the acceleration of some points and the dynamic stress concentration factor of circular hole influenced by the P-wave are studied by the use of the FEM method. In mathematics the FEM is a method in which the initial and boundary value of the partial differential-coefficient equations are transformed for a group of initial value of the ordinary differential equation (after space disperse) or a group of regular algebra equation. Then, each node and element's displacement and stress solution vs time are obtained by using the direct integral calculus method of NEWMARK. On the one hand, the artificial boundary is intercepted because the infinite field is simulated by the infinite filed intercepted from the infinite field. On the other hand, all kinds of disadvantageous influence in space-time dispersing should be sloved to reduce error.The scattering of P-wave and transient analysis problem of dynamic stress concentration are investigated to the single (double) circile hole structures in half space though the general finite element analysis software ANSYS. Not only the time curve of the node's displacement and acceleration are given, but also the stress solution vs time about circle hole is given and the influences of the radius of the radius of the circle hole and the distance to the ground on the displacement of all the nodes are discussed.