Physical Model Test on the Influence of Karst Cave under and in front of Pile on the Stability of Embedded End of Antislide Pile

Abstract

With the extensive use of antislide piles in engineering, the stability of the embedded end of antislide piles in karst areas has become increasingly prominent. When there is a cave in front of the antislide pile, the cave may be deformed under horizontal load, causing the stability of the embedded end of the antislide pile to lose its stability. Based on the similarity model theory, this study establishes two different shapes of caves (horizontal in the longitudinal direction and vertical in the longitudinal direction) beneath and in front of the rock-socketed section of the antislide pile. Using horizontal loading tests, the influence of the karst cave beneath and in front of the elliptical pile on the stability of the antisliding pile embedded end was studied, and the following relevant conclusions were obtained. (1) Compared with the model without cavities, the presence of cavities in front of and under the pile significantly reduces the horizontal bearing capacity of the antislip pile. The fracture trace initially develops from the bottom of the pile against the side of the active zone, roughly at 90° to the horizontal direction through the top plate of the cave and continues to develop under the cave until the boundary. (2) The horizontal bearing capacity of horizontal bearing pile is greatly reduced by karst cave. The karst cave under the pile has a greater influence on this property than that in front of pile and the influence of the two karst caves has a common effect. (3) Both sides of the bottom for pile and the roof of karst cave are prone to damage. Besides, the roof of the karst cave under the pile is more prone to damage for more obvious stress concentration. (4) The loading failure processes of all model can be roughly divided into three stages: gentle deformation, stable expansion of deformation, and accelerated expansion of deformation. (5) Compared with the case where there is no karst cave in front of pile, the karst cave in front of pile will increase the deformation of pile under horizontal load and the same level of load. (6) Based on the limit equilibrium method, a check calculation method for the bearing capacity of the anchored end when a cave existing in front of the pile is proposed. The verification method was verified.