滑坡防治格构梁锚杆地震动力响应分析

Dynamic Response for Framed Anchors in Landslide Prevention Under Earthquake

针对锚杆格构支护的均质土坡在地震作用下的动力响应,通过振动台模型试验,研究锚固边坡在地震作用下的动力响应差别、不同坡高锚杆在地震作用下的受力机制,揭示了均质土坡及其支护结构在地震作用下的变形破坏机理。结果表明:地震激励作用下,锚杆的动应变对低频、高量级加速度的地震波反应较为敏感;加速度量级由低→中→高变化时,锚固边坡中承担较大荷载作用的锚杆位置也发生变化,对应的调整顺序为中层→顶层→中层;地震强度足够大时,中层锚杆首先破坏,其次是底层锚杆。因此,地震荷载作用下锚固边坡的设计不仅要遵循传统的设计思想"强腰固脚",而且要对上部锚杆的锚头及坡面进行加强处理,防止受到地震浅表效应的影响,并应充分考虑大、小震作用下边坡动力响应的差异。研究结果为更加合理地进行锚杆抗震设计提供了良好的基础。

In order to study the dynamic response of homogeneous soil slope supported by anchors and lattices under seismiv loading, based on the shaking table test, the mechanism behavior of anchor bars under earthquake, and the difference of dynamic response of anchor bars at different heights were analyzed, and the deformation and failure machanisms of homogeneous soil slope and its supporting structures under seismic load were discussed. Experimental results showed, under dynamic loading, the dynamic strain of anchor was hypersensitive to low-frequency and high magnitude of acceleration of earthquake wave ; acceleration magnitude changed from low to medium to high, the position of the bolt to bear larger load also changed in anchored slope, the corresponding order was from middle to top to middle ; if the earthquake intensity was large enough, the middle anchor would be damaged firstly, followed by the bottom bolt. The traditional design idea ＂strenthening slope waist and fixing slope toe＂ should be used when an anti-seismic anchorage system is designed to make a slope stable. In addition, strengthening the anchor heads of top-row anchors and the upper slope face is a good method to protect the slope from being influenced by the seismic superficial effect. The difference of slope dynamic response should been fully considered under small or big earthquake. The results provided a reasonable foundation for the design of the anchor bars supporting under earthquake.