Evaluation of Geometric Factors on Coupled Failure Mechanisms in Loaded Slopes Stabilized with Piles

Limited-length surcharge loads acting on slopes generate three-dimensional failure mechanisms. The interaction between the pile row and the surrounding soil governs the effectiveness of pile stabilization, which can only be assessed when potential pile failure is also considered. This paper presents the results of three-dimensional analyses performed on locally loaded clay slope models stabilized with piles, where drilled shafts were socketed into an underlying sand layer. Complete (full) slope models with heights of 5 m and 10 m were analyzed to capture the influence of pile spacing on the response of the entire pile row. The analyses demonstrated four main coupled failure mechanisms in locally loaded pile-stabilized clay slopes. In cases with closer pile spacing, the failure was confined to the upper part of the slope. Pile failures led to deep-seated failure mechanisms. With an increase in pile spacing, soil arching deteriorated. For the 10 m-high slopes, pile structural failures were dominant. The effectiveness of piles in stabilizing the locally loaded clay slopes decreased with increasing slope height.