The numerical analysis method is an important method to study the stability of the slope reinforced with anti-slide pile, which can take both the mechanical behavior of the anti-slide pile and the stability of the slope into consideration at the same time. However, in the previous numerical simulation, it is hard to find a numerical model of the anti-slide pile with easy modeling, high precision and low time cost. Therefore, an anti-slide pile model coupled with the composite solid-structural element is proposed in this study. Based on this model, the influence of design parameters such as pile location and space on the stability of slope reinforced by composite anti-slide pile are studied under the free and fixed constraints of anti-slide pile top. Besides, the potential failure modes of anti-slide pile is also studied. The results show that the proposed model can realistically simulate the mechanical properties of the pile with a high calculation accuracy, and the calculation results are independent on the mesh density. When the anti-slide pile is arranged in the middle of the slope, the safety factor of the reinforced slope reaches to a maximum value. The closer to both ends of the slope, the smaller the safety factor of the reinforced slope. When the pile space is less than 3D, the potential sliding surface of the slope is divided into two independent parts, and the soil between the piles forms an obvious stress arch. When the pile space is larger than 4D, the plastic shear zone of the center soil between the piles completely penetrates, and the soil between the piles forms the reverse stress arch. When the anti-sliding piles are arranged in the middle (L-x / L = 0.5) and in the lower part of the slope (L-x / L = 0.3) with the free and fixed constraints in pile top, respectively, the anti-sliding pile is easy to bend and damage. The results have guiding significance for the engineering design of slope reinforced with anti-slide pile.
