摘要
基于极限分析上限理论,结合边坡三维旋转破坏机制和Newmark位移法,利用水平地震加速度时程曲线表征地震效应,对地震作用下土钉支护边坡三维稳定性及永久位移开展研究。通过与振动台试验对比,发现本文方法预测的土钉支护边坡破坏面和位移与试验结果大致吻合,验证了所提方法的可靠性。提出一个表征边坡中土钉强度及三维分布特征的无量纲系数Mt,探究3组Mt下边坡宽高比、c/γH、边坡倾角和土内摩擦角对临界地震加速度的影响规律,计算不同边坡倾角、土内摩擦角及Mt的位移系数设计图表,并通过对2种水平地震加速度时程曲线二次积分得到了地震积分位移表。研究结果表明:无量纲系数Mt越大,土钉支护边坡的临界地震加速度越大,地震诱发边坡位移越小,且随着土钉的长度和强度的提高,相应临界地震加速度增长率逐渐降低;边坡倾角增大会导致位移系数先增大后减小,且Mt越大时位移系数取峰值时对应的边坡倾角越大。基于边坡参数,结合临界地震加速度、位移系数和地震积分位移的设计图表,可直接估计边坡的地震永久位移值。研究结果可对土钉支护边坡工程的震后位移预测以及土钉参数取值提供参考。
Based on the upper bound limit analysis,combined with the three-dimensional rotational failure mechanism of slopes and the Newmark method,the three-dimensional stability and seismic-induced permanent displacement of soil nailed slopes were investigated by using the horizontal seismic acceleration time curve to characterize the seismic effect.Compared with the results of shaking table tests,it was found that the critical slip surfaces and displacements predicted by this method match with the test results,which verified the reliability of the proposed method.A dimensionless coefficient Mt was proposed to characterize the strength and three-dimensional distribution of soil nails in slopes.The effects of slope aspect ratio,c/γH,slope inclination and soil friction angle on the critical yield acceleration were investigated under three sets of Mt.Design charts for displacement coefficient with slope inclination,soil internal friction angle,and Mt as variable were calculated.The seismic displacement integrals tables were obtained by quadratic integration of two horizontal seismic acceleration time history curves.The results show that as the dimensionless coefficient Mt increases,the critical yield acceleration of soil nailed slopes also increases,while the seismic-induced displacement of slopes decreases,and the corresponding critical yield acceleration growth rate decreases as the length and strength of soil nails are increased.With the increase of slope inclination,the displacement coefficient increases and then decreases,and the larger Mt is,the larger the slope inclination is when the coefficient takes the peak.Based on the slope parameters,the seismic permanent displacement of the slopes can be directly estimated by combining the graphs of the critical yield acceleration,the dimensionless displacement coefficient,and the two integral tables of two typical earthquake acceleration time history.The results of the study can provide a reference for the seismic-induced displacement prediction of soil nailed slopes and the values of soil nail parameters.
作者
余家骥
黄旭东
陈志宇
王玲
阮波
潘秋景
YU Jiaji;HUANG Xudong;CHEN Zhiyu;WANG Ling;RUAN Bo;PAN Qiujing(School of Civil Engineering,Central South University,Changsha 410075,China;China Civil Engineering Construction Corporation,Beijing 100038,China;Design and Art Institute,Hunan University of Technology and Business,Changsha 410205,China;Hunan Tieyuan Civil Engneering Testing Co.,Ltd.,Changsha 410075,China)
出处
《铁道科学与工程学报》
北大核心
2025年第1期161-171,共11页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(52108388)
湖南省自然科学基金资助项目(2022JJ40611)
湖南铁院土木工程检测有限公司开放基金资助项目(HNTY2022K02)。
