Barrier Systems to Protect Critical Transportation Infrastructure from Impact-Induced Ground Vibrations

Critical transportation infrastructure includes the vast network of highways, railways, utilities, buildings and stations. The unwanted vibrations induced due to man-made activities, e.g. dynamic compaction, drop hammers and pile driving, propagate through the soil media and affect infrastructure amenities. Therefore, an attempt has been made in the current study to limit the propagation of these unwanted vibrations from reaching the critical infrastructure. The efficacy of the single and dual barriers constructed between the vibration source and the infrastructural amenities has been investigated using numerical techniques. A finite element model was developed using ABAQUS to simulate vibrations induced due to impact loads. The excitation force generated due to impact load was modelled as a pulse in the developed numerical model. Initially, the model was validated with the published literature and thereafter used to investigate the influence of the depth, width, location and number of barriers on the isolation efficacy. The results indicated that the depth of the barriers was the most influential parameter in mitigating the vibrations. The optimum depth and width for the single open barrier were observed as 1.0L_R and 0.1L_R, respectively, where L_R is the Rayleigh wavelength. However, the depth requirement for the dual barriers was significantly lesser than the single barriers. The average amplitude reduction ratio for the dual open barriers of a depth of 0.4L_R was recorded as low as 0.22.