SURFACE GROUND VIBRATION DUE TO A MOVING TRAIN IN A TUNNEL: TWO-DIMENSIONAL MODEL

Vibration of a surface of a two-dimensional (2D) elastic layer generated by a point load moving uniformly along a beam, which is located inside the layer is investigated theoretically. It is supposed that the layer possesses a small viscosity, is fixed along the bottom, and has a traction-free surface. The beam is described by the Euler–Bernoulli model and located parallel both to the surface and the bottom of the layer. The surface vibration is analysed under three types of the load, namely constant, harmonically varying and a stationary random load. For the deterministic loads, the vector displacement of an observation point on the layer surface is analyzed along with the amplitude spectrum of vibration in this point. For the random load main attention is paid to the variance of vibration at the observation point. Qualitative features of obtained results are discussed via kinematic analyses of the wave propagation in the structure.