单排与三排微型抗滑桩大型模型试验研究

为了得到土质边坡中微型抗滑桩的破坏机制及边坡的破坏模式，通过3组大型物理模型试验对单排与三排微型抗滑桩加固黏性土边坡进行了研究。在加载过程中进行了位移和桩体应变的测量，最后进行开挖观察桩体破坏形态。试验结果表明，三排微型桩具有良好的抗滑效果，其承载力较单排桩提高了51.5%，且允许滑体产生较大位移，有效延缓坡体垮塌，适用于应急抢修工程。边坡会在加桩位置向前产生弧形次生滑面，并与预设滑面贯通；对于三排桩，第3排桩前出现桩土脱空区，坡面产生纵向劈裂缝。桩体变形呈S形，发生弯曲变形引起张拉与压剪破坏，而不是岩质边坡中滑面处的受剪断裂破坏。桩身所受最大弯矩分布于滑面以上，对于三排桩，第1排所受弯矩最大，第3排其次，第2排最小。其研究结果对了解微型桩的抗滑和破坏机制具有参考意义。

Large-scale model tests of single-row and triple-row anti-slide micropiles

To characterize the failure mechanism of anti-slide micropiles and the failure mode of slope, three sets of large-scale physical model tests were carried out on the soil slopes reinforced by anti-slide micropiles in a single row and three rows. The displacements and the strain of piles during the loading process were measured and the failure pattern through excavating was observed. It is found that the triple-row micropiles behave better in anti-sliding, whose capacity is 51.5% higher than that of the single-row piles, and the sliding body can deform significantly before it completely collapses or fails, implying that the triple-row micropiles are suited to be used for the expedient treatment. Secondary sliding surface which is arch-shaped can be generated in front area of the piles and links to main sliding surface preset; for the three-row piles, pumping area between pile and soil would appear in front of the third row and longitudinal cracks come into being in the slope surface. The pile deformation displays S-shaped. The bending deformation of piles leads to tension-compression and shear failure instead of the fracture failure as at the sliding surface of rock slope. The maximum of bending moment of the pile is located above the sliding surface. For the triple-row micropiles, the bending moment of the first row piles is the largest, then the third row and that of the second row is smallest.