Abstract: Based on the factors of reinforced slope computed with Holland method and Sweden method, the tests of single index and multiple factors were designed according to orthogonality table in the paper. Associated with the example of slope with the height of 20 meters reinforced by geogrids, the sensibilities of the factors influencing on the stability of slope were analysed. In sequence, the sensibilities of factors are as follows in their magnitude order: cohesion, angle of internal friction, seism, unit weight, the reciprocation of number of geogrids layers and space between layers, number and tensile strength of geogrids, slope angle space between geogrids layers, overload in top of slope and underground water level. The discussion laid emphasis on the effects of reinforcement. If possible, backfill with high cohesion and big angle of internal friction should be adopt preferentially. When reinforcements are needed, under the condition of the same total tensile strength of reinforcement, it’s better to install more geogrids with moderate strength than less ones with high strength.

Key words: geogrids, reinforcement, slope stability, orthogonality analysis method, reciprocation