新型框架通风锚杆支护多年冻土边坡降温效果及力学效应试验研究

Experimental study on cooling and mechanical effects of new frame ventilation anchor bolt supporting permafrost slope

新型框架通风锚杆是自主研发的一种冻土边坡柔性支挡结构,具有广阔的应用前景。为了探究新型框架通风锚杆的降温效果及力学效应,设计了能够加载、变角度且可同时测得温度、水分、风速及内力的多功能冻土实验箱,并搭建了新型框架通风锚杆支护多年冻土边坡的室内试验,得到了不同时期内边坡温度、水分、风速及支挡结构内力变化规律。试验结果表明:越靠近通风锚杆,土体温度和水分变化越明显,新型通风锚杆能吸收冷量并沿轴向和径向传递和扩散,具有良好的降温效果,并保持冻土边坡的冻结状态。新型通风锚杆内风速变化规律与外界风速变化较为一致,外界风速越大,新型框架通风锚杆降温效果越明显。不同时期内,新型锚杆轴力呈抛物线型变化,冻结期轴力大于融化期,且冻结期框架内力是融化期的2~3倍。研究结果可为新型框架通风锚杆的设计和工程应用提供指导。

The new frame ventilated anchor is an independently developed flexible support structure for frozen soil slope,which has a broad application prospect.In order to explore the cooling effect and mechanical effect of the new frame ventilation anchor,a multifunctional frozen soil laboratory box was designed,and it has the functions of loading,changing angle,adapting to the shaking table,and can simultaneously measure the temperature,moisture,wind speed and internal force.And a permafrost model slope reinforced by the frame ventilation bolts was erected to investigate the variation laws of temperature,moisture,wind speed and internal force of frame ventilation bolts subjected to freeze-thaw cycles.The closer to the anchor bolts,the more obvious the change of soil temperature and moisture.The frame ventilation anchor can absorb the cold energy and transmit and diffuse it along the axial and radial direction,with good cooling effect and maintaining the frozen state of frozen soil slope.The wind speed change law in the anchor bolt is consistent with the change of the external wind speed.A large external wind speed can motivate a more remarkable cooling effect of the frame ventilation anchor bolt.In a freeze-thaw cycle,the axial force of the anchor bolt changes in a parabola,and the axial force in the freezing period is greater than that in the thawing period.And the internal force of frame in freezing period is 2-3 times that in thawing period.The results can provide guidance for the design and engineering application of the new frame ventilation anchor.