Numerical assessment of vibration damping effect of soilbags

ABSTRACT: It has been proved that soilbags can be used as an effective measure to reduce or isolate traffic-induced ground vibration. Research related to laboratory tests or field tests can be found in the literature but there have been few numerical studies on the vibration damping effect of soilbags, partly because of the difficulties in modelling the dynamic behaviour of ground and of the material within the soilbags. The present study investigated and evaluated the vibration damping effect of soilbags using a numerical method, and field testing. In the field test, a soilbag stack was set up as a vibration barrier within sandy ground and a vibrator was used as a point vibration source. The accelerations propagated from the vibration source were measured along a measurement line on the ground surface. A dynamic finite element analysis based on an elastoplastic constitutive model called the ‘t_ij subloading model' (Soils and Foundations, 44, No. 2, 53–70, 2004) was created to simulate the field test. By comparing the results with and without using soilbags for countermeasures, it was found that the soilbags could effectively reduce ground vibration, but the damping effect depended strongly on the position of the vibration source. The smaller the distance between the vibration source and the soilbag stack, the greater was the damping effect.