顺倾及反倾层状碎裂结构斜坡地震反应的大型振动台试验研究  

Large-scale shaking table test on the seismic response of dip and anti-dip layered fractured structural slopes

作　　者：王通 刘先峰[1,2,3] 袁胜洋 蒋关鲁[1,2] 胡金山[4] 邵珠杰[4] 田士军[4] WANG Tong;LIU Xian-feng;YUAN Sheng-yang;JIANG Guan-lu;HU Jin-shan;SHAO Zhu-jie;TIAN Shi-jun(School of Civil Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;Key Laboratory of High-speed Railway Engineering of Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;School of Civil Engineering,Xinjiang Institute of Engineering,Urumqi,Xinjiang 830023,China;China Railway First Survey and Design Institute Group Co.,Ltd.,Xi’an,Shaanxi 710043,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031 [3]新疆工程学院土木工程学院,新疆乌鲁木齐830023 [4]中铁第一勘察设计院集团有限公司,陕西西安710043

出　　处：《岩土力学》2024年第2期489-501,共13页Rock and Soil Mechanics

基　　金：中铁第一勘察设计院集团有限公司科研项目(No.20-06)。

摘　　要：西南艰险山区分布着大量的不同倾向的层状碎裂结构斜坡,地震作用下极易发生崩塌、滑坡等灾害,对在建的川藏铁路造成严重威胁。通过大型振动台模型试验,研究了强震条件下顺倾、反倾层状碎裂结构斜坡的动力响应、失稳破坏模式以及能量传递规律。试验结果表明:反倾斜坡的抗震性能显著优于顺倾斜坡;顺倾斜坡的破坏模式主要为拉裂-剪切-隆起-滑移型破坏,反倾斜坡的破坏模式主要为拉伸-弯曲-倾倒-崩塌型破坏;反倾斜坡的自振频率高于顺倾斜坡,顺倾斜坡的自振频率随震级的增加而逐渐降低,而反倾斜坡的自振频率在地震波幅值为0.4g~0.7g时出现反复震荡现象;顺倾斜坡存在明显的高程放大效应和趋表效应,反倾斜坡存在高程放大效应,其内部的加速度响应大于坡表。边际谱识别显示:顺倾斜坡的边际谱幅值(peak of marginal spectrum amplitude,简称PMSA)突变在坡腰上部最显著,说明该位置附近地震波的能量损失最大,反映出顺倾斜坡在坡腰上部附近形成了滑动破坏面;反倾斜坡的PMSA在坡肩处降低得最为显著,反映出坡肩部位损伤最为严重,易发生局部崩塌破坏。分析结果与试验现象能够较好地吻合,进一步揭示了不同结构类型层状碎裂结构斜坡在强震作用下的动力响应与失稳破坏模式,为川藏铁路的安全建设提供了依据。In the challenging and perilous mountainous regions of Southwest China,there are numerous layered and fractured rock slopes with varying inclinations.These slopes are prone to disasters such as collapses and landslides during earthquakes,posing a serious threat to the ongoing construction of the Sichuan-Xizang Railway.To address this issue,large-scale shaking table model tests were conducted to study the dynamic response,failure modes of instability,and energy transfer characteristics of dip and anti-dip layered slopes under strong earthquake conditions.The test results reveal that the anti-seismic performance of anti-dip slopes is significantly better than that of dip slopes.The failure mode of dip slopes primarily involves tensile cracking,shearing,uplift,and slip failure.On the other hand,the failure mode of anti-dip slopes mainly consists of tensile,bending,tilting,and collapsing failure.The natural vibration frequency of anti-dip slopes is higher compared to dip slopes.As the earthquake magnitude increases,the natural frequency of dip slopes gradually decreases.However,the natural frequency of anti-dip slopes exhibits repeated oscillations within the range of seismic amplitudes of from 0.4g to 0.7g.Dip slopes exhibit clear “elevation amplification effect” and “tend-surface effect,” while anti-dip slopes demonstrate the “elevation amplification effect.” Furthermore,the internal acceleration response is greater than that of the slope surface.Marginal spectrum identification indicates that the most significant change in peak of marginal spectrum amplitude(PMSA) for dip slopes occurs at the upper part of the slope waist.This suggests that the energy loss of seismic waves near this position is the largest,indicating the formation of a sliding failure surface near the upper part of the slope waist.For anti-dip slopes,the PMSA decreases most significantly at the slope shoulder,indicating severe damage and a propensity for local collapse in this area.The analysis results are in good agreement with the ex

关 键 词：顺倾斜坡 反倾斜坡 振动台试验 地震加速度峰值(peak ground acceleration 简称PGA)放大系数 破坏模式 损伤识别 

分 类 号：TU45[建筑科学—岩土工程]