With the popularized application of micropile for slope reinforcement, there are many kinds of pile section form, such as single steel bar, multisteel bar, and tube. In order to obtain the theoretical calculation model of horizontal capacity of micropiles with different types, numerical simulations for two common conditions, namely, soil-soil and soil-rock, were carried out to study micropile reinforced slope’s deformation and failure regulation. The dominated indicator for micropile horizontal capacity was acquired. By using the equivalence principle, four kinds of micropiles’ capacity calculation model were deduced. Then, FEM numerical analysis was used for validation. The results show that the flexural capacity of micropile is a critical and dominated indicator which should be considered seriously in slope reinforcement design. When the ultimate flexural capacity is reached, the displacement of micropile reinforced slope will increase rapidly. The primary factor affecting the flexural capacity of micropiles is pile diameter, followed by section reinforcement ratio. The calculation results of the calculation model of flexural capacity proposed in this paper are close to those of numerical ones and are safer. The calculation model can provide reference for micropile selecting and slope reinforcement design, especially for quick design of emergency engineering.

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