填方路基振动台动力破坏试验研究  

Experimental study of dynamic failure of fill subgrades using a shaking table

作　　者：李金贝[1,2] 张鸿儒[1] 李志强[2] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]交通运输部科学研究院交通环保与安全研究中心,北京100029

出　　处：《岩土力学》2011年第10期3075-3080,3096,共7页Rock and Soil Mechanics

基　　金：交通运输部西部交通建设科技项目资助(No.2008-318-221-96;No.2009-318-740-099)

摘　　要：填方路基抗震安全是西部公路建设的关键技术问题之一。以"5.12"汶川地震灾区典型填方路基为背景,采用红层软岩和石英砂为模型路基材料,设计并完成比例为1∶20的大型振动台模型试验。在满足相似律的条件下,通过输入不同地震波类型、频率和振幅,系统地研究填方路基在强地震动作用下的动力响应和损伤破坏过程。试验模型尽可能全面地模拟影响填方路基地震响应的各种主要因素,包括路基与挡墙动力相互作用、路基施工过程、边界条件等。试验结果表明,加速度沿水平方向的响应呈现明显的非线性特征;总体上,模型路基对输入地震波具有明显的放大作用,在水平向地震波作用下,沿路基坡面向上,加速度峰值放大系数呈现递增趋势,路肩附近急剧增大,在逐级增加的输入地震作用下路基发生多处开裂。试验模拟呈现填方路基在地震作用下的响应及其损伤破坏过程,确定抗震薄弱部位,为全面评价路基的抗震性能提供相应的参考。Seismic safety of high fill subgrade presents a difficult design problem,constituting one of the greatest challenges in the development of highway in West China.To study the seismic damage and dynamic characteristics of fill subgrade,firstly the fill subgrade seismic damage of Wenchuan Earthquake is investigated finding out that the main seismic damage type of fill subgrade is rip of upside and bulge of downside.The seismic response and damage of fill subgrade was studied through a shaking table test.In order to model the main factors that influence the seismic response,the model system included the dynamic interactions between the subgrade and retaining wall,construction progress,boundary conditions,etc.The model is made of red beds and quartz sand,meets the requirement of similitude.Results show that the subgrade slope has amplification effort to input seismic waves;and the effect becomes extremely prominent around the crest of the subgrade.The study also shows that the top of the retaining wall and the crest of the subgrade are the vulnerable parts of subgrade and cracks normally appear near these parts under seismic motion.The dynamic characteristics of the subgrade as well as its weak portions during earthquakes are discussed,so as to provide valuable references for seismic appraisal of subgrade.

关 键 词：填方路基 振动台 动力响应 抗震安全 

分 类 号：U416.162[交通运输工程—道路与铁道工程]