坡面锚索与坡脚抗滑桩联合加固边坡设计方法

摘要

路堑高陡边坡的加固中,二级及以上边坡坡面锚索与一级边坡坡脚抗滑桩的组合结构应用广泛,但其设计方法尚不成熟,为此,提出该组合结构的优化设计方法.首先,研究坡面单束锚索预应力对滑体各条块的作用效果;继而,通过预应力锚固后的边坡稳定性计算,获得设桩处的剩余下滑力、确定抗滑桩上的荷载,实现锚索预应力和抗滑桩被动力的协调作用;最后,以广(通)大(理)铁路某实际边坡为例,论证所提方法的设计过程.论证结果表明:该组合结构的设计可以锚索预应力占总下滑力的40％进行初算,并以抗滑桩中心间距5.0～8.0m、桩截面宽度1.0～3.0m、截面高度1.5～4.0m、嵌固段长度为总桩长的1/3～ 1/2为控制条件.%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.