Discontinuous Deformation Analysis of Seismic Failure Behavior in a Narrow Area of Railroad Ballast

The seismic failure behavior of railroad ballasts in response to earthquakes was analyzed using Discontinuous Deformation Analysis.Several sinusoidal waves with different frequencies and accelerations were inputted into the discontinuous numerical model of a railroad ballast ,which consists of an assemblage of polygonal crushed stones,rails,sleepers and a roadbed .The dependencies of railroad failure activities on frequency and acceleration were evaluated with such parameters as;increase in void volume,horizontal,vertical and angular displacements at different points with respect to the areas under the sleeper and the shoulder of ballast .The results indicated that initial dilation by the rotational behavior of the crushed stones triggers the succeeding failure process.