Behavior and analysis of stabilizing piles installed in a cut slope during heavy rainfall

In this study, the behavior of stabilizing piles installed in a cut slope is investigated using a field measurement system and analyzed considering the infiltration depth of environmental rainfall. Two cut slopes located on an express highway construction site in Donghae, Korea were selected for this study. Landslides with some tension cracks were found in the upper part of these cut slopes during the cutting process. As the primary method of slope enforcement, four rows of stabilizing piles were created, and a series of field monitoring systems was installed to measure the movements of the stabilizing piles and the slope. According to the field monitoring results, the deflection of the stabilizing piles and the deformation of the slope were significantly affected by heavy rainfall. Lumbʹs theory (1975) was used to calculate the depth of the wetting front for the case in which the rainfall intensity is equivalent to the coefficient of permeability of the soil. A slope stability analysis was performed, and the calculated depth of the wetting front and the measured groundwater level were considered in this analysis. The behavior of the stabilizing piles was calculated by the SLOPILE program (Ver. 3.0), which was used to analyze and design the slope and the piles. The expected deflections of the piles obtained from the analysis are similar to measured deflections. Therefore, the rainfall intensity can be used to calculate the depth of the wetting front, and this analysis technique very effectively calculates the slope stability and the behavior of stabilizing piles.