Abstract: Multi-row micro-pile frame structure is an effective means for slope treatment, and its theoretical research lags behind the engineering application. To study the deformation and stress characteristics and reinforcement mechanism of the structure in slope reinforcement, the centrifugal model test of the slope reinforced by multi-row micro-pile frame structure was carried out. The test results show that the deformation and failure mode of the slope in the test is creep-tensile thrust-type, which is divided into three stages: elastic deformation, plastic deformation and deformation stability. Compared with the unreinforced slope, the anti-slide stability of the slope reinforced by multi-row micro-pile frame structure is significantly improved, and the factor of safety for the slope is increased by 156%. The importance of the factors affecting the slope reinforcement effect in the test is the anchorage depth, the number of piles, and the pile spacing. As the forward thrust of landslide, the soil pressure approximately presents a triangle distribution of ‘small in the upper part and large in the lower part’ along the depth direction, acting on the pile-soil composite structure, and the bending moment curves of pile body and frame beam present the reserved ‘S’ and ‘C’ distributions, respectively. The bending moment distribution of frame transverse and longitudinal beams is significantly affected by pile arrangement. The maximum bending moments of frame transverse and longitudinal beams in 4 rows × 4 columns are similar, while the maximum bending moment of longitudinal beams in 4 rows × 3 columns is nearly three times that of transverse beams. The research results can provide theoretical guidance and design basis for the structure in engineering application.

Key words: soil slope, multi-row micro-pile frame structure, centrifugal model test, slope failure and deformation mechanism, mechanism of pile-soil interaction