Joint Reinforcement Design Method of Tieback Anchors on Slope Surface and Anti-Slide Piles at Slope Toe

In the reinforcement of high and steep slopes, joint uses of tieback anchors of the second-grade and upper-grade slopes and anti-slide piles of the first-grade slope toe are frequent. However, the design method for these combinations remains immature. In this work, a method for optimizing joint reinforcement design was proposed. Firstly the effects of the preload of a single tieback on each slice of the sliding body, and then the residual thrust and load on the anti-piles was determined by the stability calculation of the reinforced slope by tieback anchors. Thus the coordination between the preload of tieback anchors and passive load of anti-slide piles can be achieved. The proposed method is validated by an example of a slope on the Guangtong-Dali railway. The results show that the preload of the tieback anchors is suggested as 40% of the total residual thrust, and the control conditions include 5.0-8.0 m spacing between the centers of anti-slide piles, 2.0-3.0 m width and 1.5-4.0 m height of pile section, and 1/3-1/2 of the total pile length for stable layer length.