Evaluation of Dynamic Properties of Track Bed Subgrade Soils Used in Korea Using Midsize Resonant Column Test Apparatus

It is a well-known fact that dynamic properties should be considered in design and maintenance of civil structures undergoing dynamic force such as rail track. For designing of the rail tack structures, dynamic properties of track bed subgrade soil such as shear modulus (G) and damping coefficients(D) obtained in small(10% ~ 10%) to medium range(10% ~ 10%) of shear strain must be known. In this study, a Stokoe type fixed-free resonant column test apparatus was designed and built to test a medium size compacted track bed subgrade soil sample of 10 cm diameter and 20 cm height with changing water content((OMC)±2%) and confining stresses (7.5, 15, 30 kPa each). It was possible to evaluate dynamic properties of the trackbed subgrade soil so that residual settlement can be predicted using a prediction model based on the dynamic properties of the subgrade soils.