## 1 Introduction
Figure 1: Statistics on the number of and damage caused by landslides from 2010 to 2021 (data originate from National Bureau of Statistics). The second section will be devoted to the research results of single-row piles. At present, the research on buried piles mainly includes three aspects: theoretical analysis, model experiment and numerical simulation. [PERSON] et al. [12] proposed a simplified calculation method for embedding anti-slide piles in the horizontal and inclined sections of landslides and demonstrated the significant economic benefits of submerged piles in landslide treatment projects with engineering examples. GB 50843-2013 [13]_Technical Code for Construction Slope Engineering_, edited by Chongqing Urban and Rural Construction Commission and approved by the Ministry of Housing and Urban-Rural Development of the People's Republic of China, mentioned that the top elevation of buried anti-slide piles should be controlled to avoid the sliding of rock and soil from the top of piles [13]. It is mentioned in GB/T38509-2020 [14] \"Landslide Prevention and Control Design Code\" that the design safety factor of buried anti-slide pile length should not be less than 1.25 (the design safety factor is the safety factor that the design should meet according to the grade of landslide control engineering and other factors. The safety factor is the coefficient of the anti-sliding stability of a landslide and is the ratio of anti-sliding force and sliding force along the sliding surface of a landslide). For a soil landslide, the cantilever length of the buried anti-slide pile should not be less than 0.55 times the thickness of the slide body, and it is stipulated that the landslide thrust should be verified by the limit balance method [14]. [PERSON] [9] used the limit equilibrium theory and the transfer coefficient method to obtain the calculation method of the buried depth of the rear pile. Moreover, he established the relationship between the buried depth of the pile top and the stability coefficient of the slope and draws the conclusion that the stability coefficient of the slope after reinforcement decreases with the increase in the buried depth, and the internal force of the pile is also decreasing. [PERSON] [15] et al. derived the analytical solution of the buried depth of the top of the pile based on the possible failure mode of the buried-pile-reinforced landslide, combined with the transfer coefficient method and the variational method under the framework of the limit equilibrium theory, and analyzed the thrust of the sliding body in the buried section and the loaded section with the help of the rigid body limit equilibrium theory. [PERSON] [16] conducted a simple model test and numerical simulation for the buried pile, preliminarily discussed the thrust distribution rule of the pile, the buried depth and feasibility and concluded that the buried pile was more economical and optimal than the full-length pile. [PERSON]'s team [17; 18; 19; 20] conducted a series of studies on buried piles. Using the finite element strength reduction method and large-scale physical model tests, they analyzed the magnitude and distribution mode of the thrust force of the pile body and pile top and obtained the relationship between the buried depth and the stability coefficient of the reinforced slope. They obtained the conclusion that the landslide thrust after the pile is negatively correlated with the buried depth, and the pile topsoil thrust is positively correlated with the buried depth. The current research on single-row buried piles has been relatively mature. However, in large-scale landslides or important landslide control projects, because of the large sliding force, it is difficult to ensure the stability of slope or control the further deformation development of side slope. Therefore, in large-scale landslides or important landslide control projects, more of them are treated with double-row piles.