Abstract: Soil arching effect is the key research point for anti-slide piles coming into effect. Taking the stress change of soil arch as the research point， first， a reasonable arch axis for soil arch was specified， and then a new stress-reduction model for soil arch was further derived， based on which the calculation of the critical arch shape parameters of the soil arch was quantified， and last a new three-level load sharing model for landslide was proposed. Research shows that the model calculation has demonstrated an exponential reduction in the stress between and behind piles. The two equations of inclination angle at the foothold and the thickness of soil arch are more practical due to full consideration of effecting factors. According to the bearing capacity of soil arch behind and between anti-slide piles， the three-level load sharing model can be consistent with the phase characteristics of interaction between landslide mass and anti-slide pile. The research can deepen the understanding in soil arching effect theory， and can also provide theoretical guidance to the design of anti-slide piles in landslide programs.

Key words: soil arching effect; stress reduce; shape parameters of arch; load sharing model; design of anti-slide pile