Ground vibration in the vicinity of a strip load: An elastic layer on an elastic half-space

The transmission of vibrations in the near field of the surface of the ground is investigated theoretically. The mathematical model is two-dimensional, and the interior of the ground is modelled as an elastic layer overlying an elastic half-space of different material. The dynamic stiffness matrix for the problem is derived, and for free vibration this is solved as an eigenvalue problem to give dispersion curves. The “period equation” is used to give the corresponding free vibration mode shapes. The dynamic stiffness matrix is then used to study the forced response, in which the surface is assumed to be subjected to a harmonic load acting on a strip of finite width. Results presented include dispersion curves, the natural mode shapes of free vibration in the layer, attenuation of surface vibration as a function of distance from the load, and the effect on displacement at the centre of the load of varying the load width.

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