Abstract:Scattered row piles-soil-nailed wall protection structure is one of important directions of the composite soil-nailed wall. It can effectively avoid the disadvantages of controlling and evaluation the displacement of the composite soil-nailed wall. When properly employed,its protection depth can be extended and the application scope can be enlarged. Based on soil arch effect theory,the mechanism and characteristics of transferring and redistributing of the soil pressure are analyzed;and the strain characteristics of the protection(support ) structure is researched. The formula for calculating the local and holistic stability of the protection structure is brought forward;and the calculating model for analyzing the stress and stability of the protection structure is set up. Finally,the model is validated by an engineering case.