A case study integrating field measurements and numerical analysis of high-fill slope stabilized with cast-in-place piles in Yunnan, China

摘要

A high-fill slope located in Zhenxiong County, Yunnan Province, China, was designed for building placement on its top platform. A reinforcement system consisting of a geogrid, front stability piles (FSPs), retaining sheets, prestressed anchors, and rear deeply buried piles (DBPs) has been used to stabilize the slope. Two typical slope sections were selected to study the high-fill slope stability and retaining mechanism of the reinforcement system. Field measurements of the horizontal displacement and strain in the piles, as well as the anchor working load, were collected and analyzed. In addition, a series of two-dimensional finite element method (FEM) analyses combined with a strength reduction technique was conducted to analyze two selected cross sections. The results show that the retaining structure behavior is closely related to the fill construction process of a high-fill slope. The deflection of the stabilizing pile increases almost linearly with the filling height in the initial stage of fill construction. The variation in the working load of the prestressed anchor shows an offset between prestress loss and increasing fill pressure. The FEM results can provide insight into the pile-soil interaction mechanism and its contribution to fill slope stabilization. The FSPs shift the sliding surface from through the slope toe to through the top of the FSPs. The anchors can reduce the bending moment by supplying additional bearing points. The DBPs can share a portion of the sliding thrust and effectively enhance the safety factor. This paper provides a reference for reinforcement system design for similar engineering projects considering high-fill slopes.