Research On Pile-anchor-soil Interaction Of The Anti-slide Pile With Pre-stressed Anchor Cables

A largest in size, most complex in property, and typical No.1 Landslide on Sichuan-Tibetan highway was profoundly studied. The thesis introduced the engineering geological conditions, triggering and involution process, stability before and after controlling of the landslide. The controlling projects are anti-brushing wall on the foot, drainage system on the surface, frameworks with pre-stressed anchor cables, general anti-slide piles and piles with pre-stressed anchor cables. The monitoring system was applied in this landslide to have attained the displacements of the landslide, the thrust forces acting in the piles and the internal forces within the anti-slide piles. The monitoring data document that the theoretical calculation results in the design are correct and available.Researching on the present design method of retaining structure, the author found out the shortages in the design theory and method of the pile with pre-stressed anchor cables. and suggested that the affect of the pre-stressed anchor cables on the soil behind the pile should be considered completely with analyzing some monitoring data. It is also suggested that Morgenstern-Price Method should be applied to calculate the thrust force and improved the design method of pile with pre-stressed anchor cables.The concept of the coefficient of anchor extension force was introduced, that is the ration of the horizontal component of anchor extension force and that of thrust forces between two piles. It is suggest that as 0.15=m = 0.25, the trust force well matches the pre-stress acting on the piles, the forces on the anchors and pile are coordinative, and the corresponding design is economic. In design, supposing available value m, then calculating the number of anchors n.With analyzing some headache problems in project of the pile with pre-stressed anchor cables, such as pre-stress loss, corrosion of steel strand, extent of grouting, operation in water contained strata etc, the author pointed out their possible harmfulness and suggested the available methods.