Four large-scale model tests are made to monitor the dynamic response of column-net structure subgrade. The influence of loading level

loading frequency and loading times on the dynamic parameters

the pile-soil load sharing and the strains of geogrid are studied. The results show that the dynamic stress and the dynamic acceleration increase fast in the bed of subgrade and underneath trend towards stability with depth after rainfall. During the stage of cyclic loading

the stress concentration ratio increases slowly. After rainfall

the stress concentration ratio can decrease about 56.4 % to 79.5 %. Compared with the construction stage

the strains of geogrid increase and the transverse distributions remain the same form after cyclic loading. The strains of geogrid among four piles within the width of subgrade increase fast after the formation of soil arching. The peak value points of strains of geogrid appear in the centre of the slope and subgrade

which emerges as W-shape in the cross-section. The strains of geogrid between two piles increase from the centre to the slope toe of subgrade

which emerges as stair-shape. The differences of strains of geogrid between the slope and the width of subgrade decrease gradually after the formation of soil arching.