Antislide piles are set in the Zhangjiawan landslide area, where the general features of the bedrock below the slip surface include upper weak and lower hard strata. Based on a site investigation, the horizontal displacement of the antislide pile head is 14.8 cm, which is not conducive to the stability of the landslide. In the study, a displacement calculation method for the pile under trapezoidal load is proposed for a colluvial landslide controlling. Furthermore, factors affecting the deformation and internal forces of the pile were also studied. The results indicated that (1) when the embedded length of an antislide pile increases, the horizontal displacement on the pile and maximum absolute shear force decrease, while the bending moment of the pile exhibits opposite trends; (2) the relationship between maximum shear force and maximum bending moment is linear with increasing driving force of landslide; and (3) increase in the ratio of the driving force between the pile head and slip surface (q0/q1) steadily increases the horizontal displacement of the pile. The relationship between the distribution of the driving force (q0/q1) and the reasonable embedded length of a pile is a quadratic function, which can be used to determine the reasonable embedded length of a pile under the action of rectangular or triangular loads. It is very useful to use the above method to guide the design of antislide piles in similar areas.

The Yuanzishan landslide is an unstable slope in Langzhong County, located in northeast Sichuan province, China. The Guangyuan-Nanchong expressway passes through the front edge of the unstable slope, and subgrade excavation has resulted in slope deformation, which threatens the safety of the highway construction. Emergency landslide control requires reduction of the slope disturbance. This study aims to investigate the use of buried-boring piles as a potential method for emergency landslide control. A simplified calculation method was used for the design of the buried-boring piles, according to the limit equilibrium of the soil and the elastic foundation coefficient method. The measured internal force changes of the pile were compared, in order to determine the distribution coefficients of the driving force. A relationship between the driving force of the shared pile ratio and the buried depth ratios was then established. Furthermore, a variety of factors affecting the internal forces of the buried-boring pile and the lateral reaction of the soil were also studied. The results revealed that (1) there was a quadratic relationship between the driving force of the pile-shared ratio and the sliding depth ratios; (2) the maximum bending moment of the pile increased with an increase in the sliding depth ratio of the pile, following a power law relationship; (3) increasing the buried depth of the pile head reduced the influence of the pile diameter on the maximum internal forces; (4) increasing the pile diameter decreased the maximum lateral reaction of the soil. The buried-boring piles can be used in similarly unstable regions for emergency control of deforming slopes.