Discussion on Slope Stability Analysis Method of Abandoned Dreg Site Based on Spatial Effect

An abandoned dreg site is a common occurrence in construction projects. There are numerous factors that influence the slope stability including the spatial effect of the concave and convex form, and side-body-end and slope strike, which play vital roles in slope stability analysis. In order to investigate the effect of slope strike on slope stability, an abandoned dreg site in a Nuclear Power Plant was considered, of which the strike is a broken line （i.e., an angle of strike exists between the upper region and the lower region） to discuss the method of slope stability analysis. The effect of the angle of strike was then studied for potential failure mechanism of the abandoned dreg site via geotechnical field investigation and region division using a 3D-model that was constructed using ANSYS, and an analysis of the slope stability by the strength reduction method in FLAC^3D was conducted. Finally, the imbalance thrust force method was proposed, taking into consideration the angle of strike. An analysis of the effect of the angle of strike and the dip of slope for stability was then performed. The results indicate that the angle of strike has an effect on the distribution of the stress field and the capability for force transmission. Hence, slope stability will be improved with an increase of the strike angle, and safety factors will increase significantly when the strike angle is more than 60°. In addition, there is a significant increase in safety factors with an increase in the angle of strike, while the dip of the slope crest increases and the dip of slope toe decreases. The results provide a scientific reference to evaluate the stability and design treatment for slopes, where the strike is a broken line.