The stability analysis of pile-anchor retaining structure is based on the searching method of the sliding surface and the calculating theory of the safety factor. During the process of analyzing anti-sliding moment

conventional slip circle method of slices has too many assumptions. At the same time

during the process of searching for the most dangerous sliding surface

there are some problems with the grid-search method. If the rough grid is applied

the result will be less accurate. However

if the fine grid is applied

the efficiency will be lower. To solve these problems

the soil strength redundancy method is proposed in order to analyze dynamic stability of foundation pit. Also

adaptive grid-search method is used to ensure accuracy and efficiency. Finally

this paper compareds the soil strength redundancy method

the sliding surface stress method and the slip circle method of slices. The results show that the sliding surface stress method overestimates the overall stability of the foundation pit and that the slip circle method of slices cannot consider the weakening effect on the shear strength of the soil behind the pile caused by excavation. Also

the soil strength redundancy method can reflect the overall stability of the foundation pit.