Optimal design of slope reinforcement by a new developed polymer micro anti-slide pile in case of emergency and disaster relief

As a new material, polyurethane polymer has been widely used in emergency and disaster relief engineering in recent years due to the excellent engineering mechanical properties. Based on the characteristics of this material, a multi pipe grouting micro anti-slide pile is proposed in slope reinforcement, which is formed by using polyurethane polymer slurry as grouting material. Compared with traditional anti-slide pile, the polyurethane polymer micro anti-slide pile has the advantages of strong applicability, no water reaction, small disturbance, fast construction, economy and durability, and it can be adapted to emergency reinforcement of dangerous landslide. As a flexible retaining structure, polyurethane polymer micro anti-slide piles can strengthen the slope by cooperating with the forces. However, there is no report on the reinforcement of slope by polyurethane polymer micro anti-slide piles at present. In this paper, a three-dimensional multi-row polyurethane polymer micro anti-slide piles model for slope reinforcement considering different embedded depth and pile location is established. Safety factor, thrust force of landslide behind pile, length of pile and Mises stress are taken as four factors to evaluate the feasibility and the reinforcement effect of reinforcing slope with polyurethane polymer micro anti-slide pile. The optimal reliability of polyurethane polymer micro anti-slide pile for slope reinforcement is evaluated by giving different weight values to each factor through multi-factor comprehensive evaluation method. The safety factor of slope (F-s), landslide thrust behind pile and Mises stress of pile are analyzed under different embedded depth (l(e)) and pile position (p(x)). The results show that polyurethane polymer micro anti-slide piles have excellent reinforcement effect under rescue and relief tasks. With the increase of embedded depth, the safety factor of slope gradually increases and then remains stable, the best embedded depth of micro-pile is about 1/8-1/12 L-B; as the pile position is gradually away from the top of the slope, the safety factor of the slope reaches its maximum value in the middle and lower part of the slope, the optimum position of pile arrangement is 0.55-0.65 L from the top of the slope.