Study on the Evolution Law of Internal Force and Deformation and Optimized Calculation Method for Internal Force of Cantilever Anti-Slide Pile under Trapezoidal Thrust Load

Abstract

The evolution law of internal force and deformation of an anti-slide pile affects the slope stability and prevention design in a significant way. Based on the similarity theory, a test system for the bearing characteristics of a cantilever anti-slide pile was constructed, and the physical model test for the bearing characteristics of a cantilever anti-slide pile under trapezoidal thrust load was carried out. The distribution laws of internal force and deformation of a cantilever anti-slide pile were revealed, and the optimized calculation method for internal force of a cantilever anti-slide pile was proposed by taking the elastoplastic characteristics of steel bars and concrete into consideration. Furthermore, a numerical model was employed to conduct a parametric analysis of a cantilever anti-slide pile. The results show that the whole process of stress and deformation of a cantilever anti-slide pile can be classified as the uncracked stage, the cracks emerging and developing stage, and the steel bars yielding–failing stage. In the uncracked stage, the bending moment of the cantilever anti-slide pile calculated by the traditional method is smaller than that calculated by the optimized calculation method established in this paper. The traditional calculation method is no longer applicable in the stage of cracks emerging and developing. The lateral displacement and bending moment of the cantilever anti-slide pile are negatively and positively correlated with the strength of the pile material, respectively, and the influence of the deterioration of steel bars’ strength on the ultimate bearing performance of the anti-slide pile is more obvious than that of the deterioration of concrete strength. The bearing capacity of the anti-slide pile could not be significantly improved by increasing the length of the anchored section when the strength of the rock stratum embedded in anchored section was large enough. As the thrust load behind the pile increased, the difference of the bearing performances of the cantilever anti-slide pile under the uniform load and trapezoidal load increased gradually. The research results can provide guidance for the evaluation of the service performance of the cantilever anti-slide pile and the slope stability.