地震动参数对锚固岩质边坡地震响应影响权重研究

Study on the Influence Weights of Ground Motion Parameters on Seismic Responses of Anchored Rock Slope

借助FLAC3D软件建立了含软弱层的锚固岩质边坡数值模型,并利用正交设计方法,以波形、时间压缩比、幅值和持时为分析因素,设计多组具有不同地震动峰值加速度(PGA)、峰值速度(PGV)、阿里亚斯强度(AI)、绝对累积速度(CAV)、持时和特征周期的地震动,分析了地震动各参数对锚固岩质边坡位移和锚杆轴力的影响,得到了地震动各参数的影响权重。结果表明,地震作用下,坡顶处位移最大,自坡顶至坡脚位移逐渐减小;锚杆轴力沿杆长表现为中间大两头小的“人”字形分布;地震动各参数对边坡位移的影响权重由高到低依次为AI、CAV、PGA、PGV、持时和特征周期;对锚杆轴力的影响权重由高到低依次为AI、PGA、PGV、CAV、持时和特征周期。

A model of anchored rock slope with weak interlayer is established using FLAC3D program.Based on the orthogonal method,and taking wave shape,time compression ratio,amplitude and duration as analysis factors,the multiple ground motions are designed with different parameters of peak acceleration(PGA),peak ground velocity(PGV),Arias intensity(AI),cumulative absolute velocity(CAV),duration and characteristic periods.The influences of ground motion parameters on the displacement and anchor axial force are simulated,and the influence weights of ground motion parameters are discussed.The results show that:(a)the displacement at the top of slope is the largest and is gradually decreased from the top to the foot of slope under the action of ground motion;(b)the axial force along the length of bolt is small at the two ends of bolt and is distributed in a“herringbone”shape;(c)the influence weights of the ground motion parameters on slope displacements from highest to lowest is AI,CAV,PGA,PGV,duration and characteristic periods respectively;and(d)the influence weights on the anchor axial force from highest to lowest is AI,PGA,PGV,CAV,duration and characteristic periods respectively.