碎裂状顺层岩质边坡地震动力响应与破坏模式  

Seismic Dynamic Response and Failure Mode of Cracked Bedding Rock Slope

作　　者：王通 刘先峰[1,2] 侯召旭 张俊 邵珠杰[3] 田士军[3] 胡金山[3] WANG Tong;LIU Xianfeng;HOU Zhaoxu;ZHANG Jun;SHAO Zhujie;TIAN Shijun;HU Jinshan(School of Civil Eng.,Southwest Jiaotong Univ.,Chengdu 610031,China;School of Civil Eng.,Xinjiang Inst.of Eng.,Urumqi 830023,China;China Railway First Survey and Design Inst.Group Co.Ltd.,Xi’an 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]新疆工程学院土木工程学院,新疆乌鲁木齐830023 [3]中铁第一勘察设计院集团有限公司,陕西西安710043

出　　处：《工程科学与技术》2023年第2期39-49,共11页Advanced Engineering Sciences

基　　金：中铁第一勘察设计院集团有限公司科研项目(院科20–06);中铁第一勘察设计院集团有限公司科研项目(R110119H01082)。

摘　　要：西南山区存在着大量碎裂状顺层岩质边坡,在地震作用下极易引发崩塌、滑坡等灾害。为探究碎裂状顺层岩质边坡的动力响应与破坏模式,以西南山区某边坡工程为依托,通过实地调研和参考工程地质资料,对结构面的分布规律进行了详细总结,并通过赤平极射投影对边坡的整体稳定性进行了分析。在此基础上,利用离散元UDEC建立了多组碎裂状顺层岩质边坡模型,通过加载EL–Centro波和Kobe波分析边坡动力特性及破坏模式,并研究了节理参数对位移和加速度响应的敏感性规律。结果表明:坡面位移响应规律呈现先增大再减小的规律,位移响应最大位于M4处;边坡的PGA放大系数呈现高程放大效应,地震波类型会影响PGA的响应规律;地震波穿过强弱风化交界处的结构面时会消耗一定的能量,局部FFT幅值会降低;碎裂状顺层岩质边坡的破坏模式为裂隙扩展–强风化岩体滑移型破坏;节理参数敏感性分析表明,弱风化岩体区域的层理间距对位移的影响最为明显,而强风化节理间距对加速度放大影响最为明显。数值仿真分析较好地揭示了地震作用下碎裂状顺层岩质边坡的动力响应规律和破坏模式,为进一步研究此类边坡的灾变机制和防治提供了有益参考。Cracked bedding rock slopes(CBRSs) are numerous in the southwest mountainous area. The action of earthquakes often causes disasters, such as collapses and landslides. The distribution law of the structural plane is herein detailed via field research and references to engineering geological data based on a CBRS project in the southwest mountain area. Moreover, the overall stability of the slope is examined through stereographic projection. On this basis, multiple groups of CBRS models were established through discrete-element UDEC, and their dynamic characteristics and failure modes were analyzed by loading EL–Centro and Kobe waves. Further, the sensitivity of joint parameters to displacement and acceleration responses was studied. The research results demonstrate that the displacement response of the slope first increases and then decreases, and the maximum displacement response of the slope occurs at M4. The PGA amplification coefficient of the slope model clearly demonstrates the elevation amplification effect, and the type of seismic wave affects the PGA response law. The local FFT amplitude drops as the seismic wave crosses the structural plane at the intersection of strong and weak weathering. The CBRS fails under the fracture propagation–sliding failure mode of the strongly weathered rock mass. According to the sensitivity analysis of joint parameters, the spacing of strong weathered joints has the greatest influence on acceleration amplification, whereas the bedding spacing in weakly weathered rock regions has the most pronounced effect on displacement. The numerical simulation analysis reveals the dynamic response law and failure mode of a CBRS under earthquake, which provides a useful reference for further studying the disaster mechanism and preventing such slope occurrences.

关 键 词：顺层岩质边坡 风化程度 动力响应 失稳演化过程 参数敏感性 

分 类 号：TU45[建筑科学—岩土工程]