Pile-sheet Retaining Wall Spacing Research In Loess Cutting Slope

In China, loess mainly distributes in loess plateau of the northwest, north China plain and south of the northeast, in which the loess plateau takes70%of the total area of the loess distribution. With the economy’s rapid expansion and the develop-the-west strategy’s implementing, amounts of infrastructure such as railway, highway, civil aviation airport, water conservancy and so on will be constructed in loess regain. This will prompts more and more high and steep loess slope arise. Retaining structure such as normal gravity retaining wall can not accommodate the current support of the high and steep slope. Pile-sheet retaining wall, evolving from anti-slide pile, is being used to the high and steep slope support more and more.As an excellent support structure, pile-sheet retaining wall has larger slide direction resistance, easy construction, and small masonry quantity. It can reinforce both landslide and retaining slope. Besides, it need not to subject to the height restrict. Currently, the design of pile-sheet retaining wall is mainly references anti-slide pile. Firstly, according to the experience or standard to ascertain the pile diameter and pile spacing, Then take the cantilever pile method, foundation coefficient method, matrix analysis method to design the pile’s structural strength. Though this traditional method is wisely used to pile shaft design, it does not consider the arching effect to the pile-sheet retaining wall which comes from the soil that behind the pile-sheet retaining wall, which leading to that the the design of the fabric is so conservative and cause a great waste. Although some scholars have made a study of the soil-arch effect, indicated the relation of the pile spacing and the soil-arch effect and also give a calculated mode of the reasonable pile spacing, all of these are based on anti-slide pile and don’t take account of the effect of the test panel in the piles to the slip mass. So, according to the soil-arch effect to the pile-sheet retaining wall, finding a logical pile-sheet retaining wall spacing has a favorable theoretical significance and practical application value to optimize the design of the pile-sheet retaining wall. This paper summarizes the current study situation of relationship between anti-slide pile spacing and soil-arch, and basing on the soil-arch effect it also puts forward a logical pile-sheet retaining wall spacing data range. Taking the pile-sheet retaining wall of DK1+961.6～DK2+020of Tian-ping railway as the object of study and using the method of numerical modeling, it analyzes the stability of the loess slope and discusses that how the deformation behaviour of the pile-loess stress effect on the pile spacing in the model of anti-slide pile and pile-sheet retaining wall. It also optimizes the loess cutting pile-sheet retaining wall spacing of DK1+961.60～DK2+020of Tian-ping railway.