Study on anti-sliding bearing characteristics of slope reinforced by spiral steel piles
At present,studies on the pile-soil mechanism and anti-sliding bearing characteristics of spiral steel piles for slope reinforcement are rare,which limits their popularization and application.Therefore,based on the FEM and the pile-slope decoupling design analysis method,a simplified method suitable for slope models reinforced with spiral steel piles was proposed,and the simulation effects of the simplified model pile-soil interaction and the accuracy of the anti-sliding force calculation were verified.Then,finite element models of spiral steel piles and equal-diameter steel pipe piles were established,and their mechanical properties were compared and analyzed to reveal the stress mode of spiral steel piles.The results show that the difference between the displacement value of the pile top calculated by the simplified method and the field measured value and the peak value of the bending moment at the sliding surface is within 10%.Moreover,under the same anti-sliding force,the displacement difference between the simplified model and the three-dimensional pile-soil model is within 5%,indicating that the simulation accuracy of this simplified method can meet the requirements.In terms of the anti-sliding bearing characteristics,when the pile top experiences 5 cm of displacement,the anti-sliding force of the spiral steel pile is 15%greater than that of the circular pile.When the same anti-sliding force is generated,the displacement of the spiral steel pile top is 22%less than that of the circular pile top.When the spiral steel pile bears the thrust of the landslide,it first resists the thrust of the landslide through the deflection of the pile body.The friction and extrusion between the spiral blade and the surrounding soil are continuously enhanced with increasing displacement of the landslide.The blade in the sliding shear zone warps and deforms to resist the thrust of the landslide by forming a reverse bending moment.The blades in the parallel sliding zone and the anchorage zone undergo relative displacement in the axial direction,which mobilizes the spiral blades to generate end resistance and transfer it to the sliding surface to increase the anti-sliding force,thus changing the distribution of displacement field and stress field of soil around the pile,enhancing the cooperative working ability of the pile and soil,and playing a good role in stress diffusion and transfer.The research results can provide a reference for the calculation of bearing characteristics and reinforcement design of spiral steel piles.
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