生态框架结构加固浅覆盖层边坡的地震动力响应  

Seismic response of shallow overburden slope reinforced by ecological frame structure

作　　者：牛家永 张建经[1] 张灏蒸 张旭皓 何俊松 江学良[2] NIU Jiayong;ZHANG Jianjing;ZHANG Haozheng;ZHANG Xuhao;HE Junsong;JIANG Xueliang(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;School of Civil Engineering,Central South University of Forestry and Technology,Changsha 410004,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]中南林业科技大学土木工程学院,湖南长沙410004

出　　处：《地震工程与工程振动》2022年第5期70-82,共13页Earthquake Engineering and Engineering Dynamics

基　　金：国家重点研发计划项目(2017YFC0504901);国家自然科学基金项目(31971727)。

摘　　要：针对川西峡谷区公路沿线广泛分布的浅覆盖层边坡形式,并结合地区特点及边坡震害现象,设计了一种新型生态耐震型框架结构,并开展了缩尺比例为1:10的大型振动台模型试验。研究结果表明:(1)坡面和基岩面的加速度峰值(PGA)放大系数和Arias强度放大系数随高程和激振强度均表现出相同的变化规律,Arias强度放大系数适用于表示高程放大效应,而PGA放大系数在分析激振强度的影响时更有优势;(2)利用传递函数和傅里叶谱值比识别出了边坡的4阶自振频率,随着地震波加载进行,各阶自振频率均有所下降,边坡对与其自振频率接近的地震波表现出选择性放大作用;(3)边坡高程对地震波能量具有聚集效应,能量谱幅值沿浅覆盖层表面呈递增趋势,能量分布有由低频向高频转移的趋势;(4)生态耐震型框架结构的整体稳定性较好,强震作用易造成坡肩和框格内发生剥落、掉块现象,应结合植被护坡技术以实现更好的生态防护效果。Combined with the regional characteristics and slope earthquake damage phenomenon in the canyon area of Western Sichuan,a new type of ecological earthquake-resistant frame structure was designed and a large shaking table model test with a scale of 1:10 was carried out in view of the shallow overburden slope widely distributed along the highway.The results show that:(1)The peak ground acceleration(PGA)amplification coefficient and the Arias intensity amplification coefficient of the slope surface and bedrock surface show the same change with elevation and excitation intensity.The Arias amplification coefficient is suitable for expressing the elevation amplification effect,while the PGA amplification coefficient is more advantageous in analyzing the influence of the excitation intensity.(2)The fourth-order natural frequency of the slope is identified by transfer function and Fourier spectrum ratio.The natural frequencies decrease with the increase of seismic excitation,and the slope shows a selective amplification effect on the seismic wave whose natural frequency is close to the slope.(3)The slope elevation has aggregation effect on seismic wave energy,and the amplitude of energy spectrum increases along the surface of shallow overburden,and the seismic wave energy distribution shifts from low frequency to high frequency.(4)The ecological frame structure has good overall stability,while strong earthquakes can cause spalling and block falling on the upper part of slope.The vegetation slope protection technology should be used simultaneously to achieve better ecological protection effect.

关 键 词：浅覆盖层边坡 竹制框架-锚杆 振动台试验 动力响应规律 破坏模式 

分 类 号：TU435[建筑科学—岩土工程]