Mechanism Of Anti-sliding Composite Micro-piles

For increasing application of the composite micro-piles in slope or landslidereinforcing, and the advantages of convenient construction, wide application rangecompared with the traditional anti-sliding piles, this paper analyses the mechanism ofcomposite micro-piles in landslide reinforcing, providing theory basis for engineeringapplication, and having important practical significance.Based on the model test and numerical simulation of composite micro-piles inreinforcing landslide, detailed and deep analysis to bearing behavior, load transfermechanism, inner force and deformation mechanism and failure mode of compositemicro-piles in reinforcing landslide has been made in the paper. The main results ofthis paper are as follows.(1) For the micropiles with rectangular composite section, the bearing capacity isgreater when the distance between two rows along landslide thrust direction isbetween four times and six times pile diameter. And for the micropiles with roundcomposite section, the bearing capacity is greater when the pile spacing is betweenfour times and six times pile diameter.(2) When the slip surface in the composite micro-piles position is nearlyhorizontal and the anti-sliding property of micropiles is full played, the front pilesbear greater landslide thrust for the rectangular composite section micropiles, andpartial landslide thrust is transferred to middle and back piles via soil between piles,which is relation to the properties of soil between piles. When the slip surface in thecomposite micro-piles position is inclined, the landslide thrust carried by middle andback piles not only includes that transferred via soil between piles, but also includesthat generated by the corresponding sliding mass.(3) The inner force and deformation mechanism of anti-sliding compositemicro-piles is relation to the pile spacing, arrangement form, value of landslide thrust and properties of soil between piles. Meanwhile, the mechanism is changing by theincreasing of load. In addition, the coupling beam on the top of piles has importanteffect on the inner force and deformation mechanism.(4) When the slip surface is nearly horizontal, the micropiles above the slipsurface are translated, and the anti-sliding composite micro-piles mainly occurbending failure. When the slip surface is inclined, the anti-sliding compositemicro-piles occur compression bending failure if the rock or soil properties above theslip surface are poor, while it occurs compression bending failure and the shearingstress is also important if the rock or soil properties above and below the slip surfaceare good.