The study of frost heave mechanism of high-speed railway foundation by field-monitored data and indoor verification experiment

Abstract

Due to the rigid deformation limit of high-speed railways, the anti-frost heave design has become a critical concern in seasonally frozen regions. In this study, the authors explained the frost heave mitigation techniques adopted for the high-speed railway between Harbin and Dalian in northeast China and then presented the thermal, deformation, and water content data monitored on the Gongzhuling test site. According to these data, the authors proposed the possible frost heave mechanisms of the high-speed railway foundation. The foundation is composed of well-graded gravel with cement and A/B group fill, which are treated as non-frost-susceptible materials in general. Based on the monitored data, the authors found that the surface layer (0–0.5 m) contributed most to the total frost heave and this might be caused by local water accumulation inside the foundation (0.6–1.2 m). In order to demonstrate the frost heave ability of these “non-frost-susceptible” materials, the authors conducted an indoor frost heave test with a mixture of gravel and 3% Kaolinite clay. Through this experiment, it was demonstrated that, with sufficient water supply, gravel with a limited amount of fine material can produce significant frost heave. Accordingly, we can conclude that the accumulated water inside high-speed railway foundation causes the frost heave deformation. Therefore, the treatment of the water accumulation within the fills needs to be considered for frost heave elimination or prevention.