Frozen Stagnant Water and Its Impact on Slope Stability at Heifangtai Terrace, China

摘要

Frequent occurrence of landslides during the transition period between winter and spring has been observed in the Heifangtai terrace, Gansu, China.To explore whether stagnant water exists or not and reveal its effect on slope stability, a monitoring network was established, incorporating monitoring factors of air and ground temperature, pore-water pressure, and groundwater level.Based on the monitoring results, seasonal freeze-thaw effect was observed which can be further divided into yearly cycling process including the partially frozen period in early winter, the totally frozen period in deep winter, the freeze-thaw period in spring, the melting period in summer, and also a daily cycling process owing to daily temperature changes.The maximum value of stagnant-water level was 2.5 m with influence distance of 3om horizontally into the slope.Slope stability during the freeze-thaw period was numerically simulated with the FLAC3D software.The results show that the factor of safety changes from 1.19 to 1.09 before and after the freeze-thaw action.