季节冻土区框架锚杆支护边坡地震动力响应简化计算方法  

Simplified Calculation Method for Seismic Dynamic Response of Frame Anchor-supported Slopes in Seasonally Frozen Regions

作　　者：董建华[1,2] 吴晓磊 师利君 连博 DONG Jian-hua;WU Xiao-lei;SHI Li-jun;LIAN Bo(Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province,Lanzhou University of Technology,Lanzhou 730050,Gansu,China;Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,Gansu,China)

机构地区：[1]兰州理工大学甘肃省土木工程防灾减灾重点实验室,甘肃兰州730050 [2]兰州理工大学西部土木工程防灾减灾教育部工程研究中心,甘肃兰州730050

出　　处：《中国公路学报》2023年第5期75-87,共13页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52178335,51778275);中央引导地方科技发展资金项目(YDZX20216200001739);陇原青年创新创业人才(团队)项目(2020RCXM120);兰州市十大科技创新项目(2020-2-11);甘肃省知识产权局高价值专利培育和转化项目(20ZSCQ034);甘肃省基础研究创新群体项目(20JR10RA205)。

摘　　要：为了研究地震作用下季节冻土区框架锚杆支护边坡体系的地震动力响应变化规律,考虑到季节冻土区边坡土体的季节分层特征,将未冻结土层处理为黏弹性Winkler地基模型,冻结层处理为中间剪切层,框架立柱处理为Euler-Bernoulli弹性梁,用线性弹簧和阻尼器来模拟锚杆锚固段与周围土体的相互作用,建立了季节冻土区框架锚杆边坡支护结构简化动力计算模型。基于D'Alembert原理并引入Dirac函数,给出了冻结期和融化期时框架-锚杆-边坡支护体系的运动方程;其次通过振型叠加法对其进一步解耦变换,并采用隐式时域逐步积分法对解耦后的体系方程组进行求解,最后将提出的计算方法应用于工程算例,且与振动台试验结果进行了对比分析。结果表明:相同地震波作用下,坡顶处加速度大于坡底,同一位置处的融化期峰值加速度比冻结期大,具有季节差异效应和高程放大效应;同时考虑冻胀和地震作用时冻结期的锚杆轴力和立柱弯矩大于地震作用时融化期的锚杆动轴力和立柱动弯矩;加速度、轴力等振动台试验结果与理论计算值在总体趋势上较为一致,即提出的计算方法能够刻画地震作用下季节冻土区框架锚杆支护结构工作状态。研究结果可为季节冻土区框架锚杆支护边坡抗震理论设计提供一种新思路。To study the variation law of the seismic dynamic response of a frame anchor bolt-supported slope in a seasonally frozen soil area during earthquakes,the seasonal stratification characteristics of the slope soil in the area were considered.The unfrozen soil layer was treated as a viscoelastic Winkler foundation,the frozen layer as an intermediate shear layer,and the frame column as a Euler-Bernoulli elastic beam.Using a linear spring and damper system to simulate the interaction between the anchor bolt anchorage section and surrounding soil,a simplified dynamic calculation model of the frame anchor bolt slope support structure in the seasonal frozen soil area was established.Based on the D'Alembert principle and Dirac function,the motion equations of the frame anchor bolt slope support system in the freezing and melting periods were stated.Next,the decoupling method was applied to the engineering vibration system,and the superposition method was used to further analyze the results through implicit transformation in the time domain.The results indicate that,under the action of the same seismic wave,the peak acceleration in the melting period is greater than that in the freezing period,showing the effect of seasonal differences.Moreover,the response of the total axial force acting on the bolt and the total bending moment acting on the column in the freezing period(with the combined action of frost and earthquakes)is greater than that in the melting period(with earthquakes only).The shaking table test results of the acceleration and axial force are consistent with the theoretical calculation values and the overall trend,i.e.,the calculation method proposed in this study can effectively describe the working state of the frame anchor bolt support structure in seasonally frozen soil areas during earthquakes.The research results can provide a new perspective for the seismic theoretical design of frame anchor-supported slopes in seasonally frozen soil areas.

关 键 词：道路工程 季节冻土边坡 动力计算方法 D'Alembert原理 框架锚杆支护 动力响应 

分 类 号：U416.1[交通运输工程—道路与铁道工程]