Abstract: From the perspective of spatial effect and synergistic effect, and relying on a specific example ofthe dump site engineering, the stress-strain rule of the dump system was analyzed based on 2D & 3Dstrength reduction methods. The results show that the stability factor of dump slope meets the safety standard under different working conditions, the system keeps synergistic stability, and the dump stackingprocess is feasible and rational. The results of stability factor and potential sliding trend are consistent be-tween 2D plane strain and 3D synergistic effect. Thus, the space clamping effect of topographical sitewhich dump locates is not obvious, transferring of horizontal stress and containment of displacement areimited, It has a certain guiding significance to the production management of the dump.

Key words: slope stability:;strength reduction method, space effect, synergistic stability