Vibration Propagation In Subsoil: In-Situ Testing And Numerical Analyses

This paper presents results obtained with the use of accelerometers during in-situ testing and its comparing with results from numerical simulations. Horizontal accelerations of propagating impulses caused by driving the prefabricated piles were recorded. Range of the quakes as well as amplitudes of longitudinal and transverse horizontal accelerations of propagating vibrations on the terrain surface were determined.

The recorded results were used to calibrate the numerical model of the finite element method. The most important factor influencing the propagation of impacts is the phenomenon of damping of the propagating wave in the soil. The mechanism of damping proposed by Rayleigh was used in the analysis, which, when selecting the appropriate parameters of the model, is able to realistically simulate the observed phenomena. The soil, in which the propagation of impulses occurred, was described with the use of linear-elastic model. Modulus of deformation correspond to the values of small deformations, which occur during the wave propagation in the subsoil. The impulse giving vibrations was caused by the falling hammer on the driven pile. The axial symmetry of the border condition was used in the analyses.

The results of numerical simulations were compared with the results of field measurements of accelerations at different distances from the source of vibration. A good consistency of acceleration amplitudes in the direction of vibration propagation was achieved and it depended on the distance from location of the driven pile. The obtained results will be used in the future to assess the extent of the impacts on the environment and values of acceleration on elements located in the vicinity of the structure.