ISSN 1003-8035 CN 11-2852/P

    锚索框架-抗滑桩加固堆积体高边坡力学行为模型试验

    Model test on mechanical behavior of high accumulation slopes reinforced by prestressed anchor cable frames and stabilizing piles

    • 摘要: 锚索框架与抗滑桩联合结构是加固堆积体高边坡的可行措施之一。为深入揭示锚索框架-抗滑桩结构加固堆积体高边坡的力学行为特征,依托坡高约60 m的实际高边坡工程进行了几何相似比为1∶20的静力模型试验,测试得到了在坡体顶部逐级加载情况下坡面位移以及锚索、框架梁与抗滑桩的受力特征。结果表明,坡面水平位移随荷载呈非线性增大,可分为线弹性小变形、弹塑性变形、塑性大变形等3个阶段,坡体变形区主要位于中上部;上部锚索框架是发挥加固作用的主体,框架中的横梁与纵梁弯矩分别呈单向与双向“M”型分布特征,横梁最大弯矩约为纵梁的0.3~0.4倍;抗滑桩最大弯矩位于距桩底高约0.4倍桩长处。基于模型试验的数值模拟分析得到,坡体加固前后的稳定系数分别为1.11、1.33,失稳破坏模式由加固前的整体深部滑动变为加固后的中上部局部滑动。采用弹性地基梁模型对框架梁与抗滑桩进行了理论分析,结果显示,理论分析与数值模拟相对于模型试验的纵梁、横梁、抗滑桩的最大弯矩误差分别为3%与7%、18%与8%、8.5%与6.2%,三者相互印证。研究结果揭示了多级锚索框架与单排抗滑桩联合加固坡体的作用机制,可为实际堆积体高边坡加固工程设计提供科学指导与参考。

       

      Abstract: The combined structure of prestressed anchor cable frames and stabilizing piles is an effective measure for reinforcing high accumulation slopes. To thoroughly reveal the mechanical behavior of such combined structures in reinforcing high accumulation slopes, a series of static model tests with a geometric similarity ratio of 1∶20 were carried out based on a practical high slope about 60 m in height. The slope surface displacements and mechanical characteristics of anchor cables, frame beams and stabilizing piles under step-by-step loading at the slope top were measured. The results show that the slope surface horizonal displacement increases nonlinearly with load and can be divided into three stages: linear-elastic small deformation, elastoplastic deformation, and large plastic deformation. The deformation zone is mainly located in the middle and upper parts of the slope. The upper prestressed anchor cable frames act as the main reinforcing component. The bending moment of the transverse beams shows a one-way distribution, while that of the longitudinal beams shows a two-way “M-shaped” distribution; the maximum bending moment of the transverse beam is about 0.3~0.4 times that of the longitudinal beam. The maximum bending moment of the stabilizing pile occurs at approximately 0.4 times the pile height above the pile base. Numerical simulation based on the model test shows that the slope stability factors before and after reinforcement are 1.11 and 1.33, respectively, and the failure mode changes from overall deep-seated sliding to local sliding in the middle and upper parts. Theoretical analysis of frame beams and stabilizing piles based on the elastic foundation beam model shows that the maximum bending moment errors of longitudinal beams, transverse beams and stabilizing piles between theoretical analysis, numerical simulation and model test are 3% and 7%, 18% and 8%, and 8.5% and 6.2%, respectively, indicating mutual verification among the three methods. The research reveal the reinforcement mechanism of multi-stage prestressed anchor cable frames combined with a single row of stabilizing piles, which can provide scientific guidance and reference for the engineering design of high accumulation slope reinforcement.

       

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