自适应锚索锚固岩质边坡地震动力响应分析

强震作用下常规锚索往往会因材料变形能力不足导致应力过载而被拉断，一旦锚索失效将直接危及整个锚固结构的安全。为研究自适应锚索的动力响应规律以及在自适应锚索支护下锚固边坡的动力特性，以新型抗震锚索为原型，设计自适应锚索锚固岩质边坡试验模型，并利用振动台试验系统对试验模型进行加载。试验中采用正弦波、天津波、EI波以及Taft波等4种地震波进行研究，监测锚索的应变和边坡动力响应。结果表明：锚索的轴力和地震波幅值、类型、地震激励频率等因素密切相关；锚固边坡坡面加速度及位移沿边坡高程均有不同程度的放大，相对于无锚索支护边坡，锚固边坡坡面加速度和位移峰值均有减小；自适应锚索随着预设滑移恒阻力的不同，锚索会产生不滑移、瞬间滑移、逐步滑移3种工况，对应的锚索应变时程曲线和锚固边坡动力安全系数时程具有显著不同的特征；自适应锚索滑移工况下，滑体的安全系数虽然有局部减小的阶段，但是锚固结构的安全储备较大，可适应边坡大变形和瞬态冲击荷载的作用。试验结果可为强震区路堑边坡的支护和自适应锚索抗震设计提供一定参考。

Seismic dynamic response of rock slope anchored with adaptive anchor cables

At the instant of the occurrence of an earthquake, the conventional prestressed anchor cables tend to break due to the insufficient deformation ability suddenly. Once the failure of the anchor cable occurs, the safety of the entire anchorage structure is endangered. This study aims to investigate the seismic response of the adaptive anchor cables and the corresponding dynamic characteristics of the anchored slope. The experiments for the rock slope with adaptive anchor cables are conducted based on a new type of anti-seismic anchor cable as a prototype and accordingly loaded by the shaking table test system. In the experiments, four kinds of seismic waves are applied, such as sinusoidal wave, Tianjin wave, EI wave and Taft wave. The real-time strain of the cables and corresponding seismic response of the slope are monitored. The results show that the axial force of anchor cables is closely related to the amplitude, type, seismic excitation frequency of the seismic wave. The acceleration and displacement on slope surface are enlarged with different elevations, and the peak acceleration and displacement decrease compared to the rock slope without anchor cables. With different values of preset slipping constant resistance of adaptive anchor cables, the anchor cables produce three slip modes such as non-slip, instantaneous slip and gradual slip. The corresponding time history curves of cable strain and dynamic safety coefficient of the anchored slope are identically different. Under the condition of the cable slipping, the safety coefficient of the slope decreases partially, whereas the safety capacity of the anchored structure is large enough to suit for the large deformation and transient impact loads on the rock slope. Therefore, the experimental results provide references for the study on the roadway slope supporting and anti-seismic design of the adaptive anchor cables in the strong earthquake area.