ABSTRACT
Soil pumping phenomena is a wide issue in traditional railway structures. A newly built railway structure from top contains rails, slippers, ballasts, sub-ballasts, soil foundations. With the infiltration of rainfall or groundwater, the soil foundation will become saturated. After the repeated loading from trains passing through performed, the soil would be more saturated and squeezed into the voids inside sub-ballasts or ballasts. The pumping effect than initialed and the pumping paths started to scurry. This purpose of this study is to find the paths of pumping materials by in-situ GPR inspection and appropriate interpretation, and then evaluate the mechanism of soil pumping. The result shows that only simple and repeated loading on a point seems not be able to trigger pumping phenomenon, besides, the materials of soil are not only mud but also others can be pumping out.
