Simulation study on slope protection effect of composite inclined micro-pile groups

This paper addresses the challenge of establishing a micro-pile group excavation platform on a steep slope, where significant disturbances to the original slope can lead to instability. To mitigate this issue, a differential layout was proposed that incorporated inclined connecting beams. In this configuration, the front row of piles was driven at an angle. In contrast, the rear row was installed vertically, resulting in a composite micro-pile group structure with inclined connecting beams. An in-depth analysis of this structure’s deformation and mechanical characteristics was conducted using the finite element strength reduction method. The findings indicate that this design enhances the coupling among the various components of the micro-pile groups, significantly improving overall integrity and increasing the stability factor by over 27%. The inclination of the front row of piles reduces the displacement, bending moment, and shear force experienced by the mountainside piles, with reductions reaching up to 45%. This effect becomes more pronounced as the inclination angle of the front row increases. When the front row of piles was inclined to the optimal angle of 25°, the maximum shear force values experienced by the three rows of mountainside piles are 0.67, 0.60, and 0.41 times those observed with vertical front row piles, respectively. Additionally, the displacement at the top of the mountainside piles was only 23.8% of that of conventional vertical piles. These research findings provide a theoretical basis and reference value for the design of this structure.