双排式钻孔抗滑桩设计及计算方法研究

Study of Design and Calculation Method on Double-row Drilling Anti-slide Piles

双排抗滑桩已经在滑坡治理中使用,但其计算理论还缺乏共识。双排式钻孔抗滑桩主要承受滑坡推力,可认为桩的竖向变形为零,基于桥梁多排桩基桩内力和位移计算理论,可将位移法三元一次方程组简化为二元一次方程组,刚度系数由9个减少到4个,以简化求解桩身内力和位移分布。基于桥梁桩基承台计算理论并结合工程实例,建立双排式钻孔抗滑桩连梁刚接时连梁高度的近似计算公式,并建议计算连梁高度时乘以0.7～0.9的折减系数。应用于工程实践发现：在滑坡推力较大时,采用双排式钻孔抗滑桩比单排桩施工进度快、安全性好及造价低;方法与刚架模型计算方法相比,发现刚架模型的计算结果偏于保守,不同的桩底支承条件时计算结果相差较大,使用时当嵌固段岩石完整坚硬且嵌入较深时,建议按固定支承处理,当嵌固段岩石完整但嵌入不深或者嵌入较深但岩石风化破碎严重时,建议按铰支承处理。

Double-row anti-sliding piles have been used in the landslide,but its calculation theory is lack of consensus. Double-row drilling anti-sliding piles mainly bear landslide thrust,piles vertical deformation can be thought of as zero,based on the bridge multi-row foundation piles internal force and displacement calculation theory,the displacement method is ternary linear equation reduced to two linear equation group,stiffness coefficient was reduced from 9 to 4,in order to simplify the solution of pile body internal force and displacement. Based on the bridge theoretical calculation of pile,cushion cap and engineering example,the establishment of Double-row anti-sliding piles approximate formula for calculating the height of the coupling beam when the beam rigid,and recommended reduction multiplied by 0. 7 to0. 9 when calculating the coupling beam height. The application in the engineering practice found： in the landslide thrust is large,using Double-row drilling anti-sliding piles construction progress faster than single row of piles,good safety and lower cost; This method compared with the rigid frame model calculation method,found that the calculation results of rigid frame model tend to be conservative,the pile supporting conditions of different calculation results is difference larger,when used as embedded segment of rock hard and embedded deep,complete suggestion according to fixed bearing processing,when the built-in embedded rock complete but not deep or embedded deep but rock weathering broken serious,hinged support treatment is recommended.