Abstract: With considering the friction between a micropile and the surrounding soil mass, a new design calculation model of single anti-slide micropile is developed; and a detailed calculation algorithm is presented. Based on the deformation characteristics of micropile in reinforcing a slope, the interaction mechanism between the micropile and the surrounding soil mass is analyzed, and the friction between the micropile and the soil mass is introduced into the force analysis of single anti-slide micropile. According to the different loading distributions along different parts of the micropile, the micropile is divided into three parts along its length, namely, the friction part, the landslide thrust part and the anchoring part. The governing equations for the deformation of different sections of the micropile are derived. The governing equations are solved by using the initial parameter method, and the internal force distribution and deformation characteristics are determined. The calculated results show that, under the action of a landslide thrust, the deformation of micropile mainly occurs near the sliding surface and the upper parts of the pile. The internal force and bending deformations near the sliding surface are larger than those at the other parts of the micropile. Along the friction part of the micropile, the bending deformation is small, and the relatively small bending deformation leads to nearly horizontal movement of the micropile. The friction is an important part of the interaction between micropiles and the surrounding soil mass, and it can significantly reduce the bending deformation of the micropile, so that the landslide displacement can be effectively controlled.

Key words: micropile, friction, landslide, slope reinforcement, calculation model, initial parameter method