锚杆框架梁柔性外锚头减震性能振动台模型试验研究  

Shaking table test on seismic performance of anchoring frame beam with flexible external anchor heads

作　　者：周文强 蒋良潍[1,2] 罗强[1,2] 肖卓琦 罗義錬 魏明 ZHOU Wen-qiang;JIANG Liang-wei;LUO Qiang;XIAO Zhuo-qi;LUO Yi-lian;WEI Ming(School of Civil Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031 China;MOE Key Laboratory of High-Speed Railway Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031 China;School of Transportation Engineering,East China Jiaotong University,Nanchang,Jiangxi 330013,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031 [3]华东交通大学交通运输工程学院,江西南昌330013

出　　处：《岩土力学》2025年第4期1163-1173,1186,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52078435);2024年度江西省职业早期青年科技人才培养专项(No.20244BCE52132)。

摘　　要：锚杆框架梁在高烈度地震作用下存在节点处锚杆断裂、拔出而整体失效的破坏风险。基于在框架梁节点外锚头设置缓冲弹簧的柔性减震理念,设计并开展几何比尺为12的浅覆盖层-基岩边坡振动台模型试验。输入高烈度地震的人工合成波和汶川地震波,对比研究设置柔性外锚头对模型坡体振动加速度、锚杆轴力等地震响应特征的影响,分析锚杆轴力减载比随缓冲弹簧刚度的变化规律,探究柔性外锚头对锚杆地震能量响应及振动累积损伤的抑制效果。研究结果显示:设置柔性外锚头后,坡体加速度Arias强度沿高程的放大系数有所减小;随缓冲弹簧刚度减小,锚杆动轴力减载效果显现,减载比为72%~89%,且锚杆震后预应力变化幅度降低;锚杆动轴力的频谱分析和锚固界面线性累积损伤计算表明,易引起结构损伤的中高频段能量响应显著减弱,锚杆体受拉疲劳累积损伤及锚杆-砂浆锚固界面剪切累积损伤程度均明显减小,采用柔性外锚头可有效控制高烈度地震过程中的结构损伤。Anchoring frame beams are at risk of anchor bolt fracturing or pulling out at joints,which can lead to overall failure under high-intensity seismic action.Based on the concept of flexible damping,buffer springs were installed at the external anchor heads of frame beam joints,and a shaking table model test was conducted on a shallow overburden-rock slope with a geometric scale of 12.The seismic responses,including slope acceleration and anchor bolt axial force,were compared with and without the flexible external anchor heads under high-intensity seismic ground motions(artificial seismic waves and Wenchuan earthquake wave).Specifically,the variation in the anchor bolt force reduction ratio with different buffer spring stiffnesses was analyzed,and the benefits of spring anchor heads on seismic energy response and vibration-induced cumulative damage in anchor bolts were explored.The research results indicated that installing flexible external anchor heads led to a reduction in the amplification factor of Arias intensity.As the stiffness of the buffer spring decreased,the reduction ratio of the anchor bolt dynamic axial force ranged from 72%to 89%,and post-earthquake prestress loss of the anchor bolts was effectively reduced.Spectral analysis of anchor rod dynamic axial forces and linear cumulative damage calculations at the anchoring interface demonstrated that the energy response in the mid-to-high-frequency range was significantly attenuated,which could lead to structural damage.Both the cumulative tensile fatigue damage of the anchor bolt and the cumulative shear fatigue damage at the grout-anchor interface were both significantly reduced.The adoption of flexible external anchor heads effectively controlled structural damage during high-intensity seismic events.

关 键 词：锚杆框架梁 柔性外锚结构 振动台试验 时频特性 线性累积损伤 

分 类 号：TU452[建筑科学—岩土工程]