地震荷载作用下层状岩质开挖损伤斜坡的变形破坏机理
文献类型：学位论文
| 作者 | 阿发友 |
| 学位类别 | 博士 |
| 答辩日期 | 2011-05-30 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 孔纪名 |
| 关键词 | 层状岩质斜坡 开挖损伤 地震荷载 变形破坏机理 |
| 其他题名 | The Deformation and Failure Mechanism of the Excavation Damage Layered rocky slopes under the Action of Seismic Load |
| 学位专业 | 岩土工程 |
| 中文摘要 | 汶川地震引发了大量的山地灾害，其中开挖损伤斜坡成为山地灾害的集中爆发区。而层状岩质斜坡在汶川地震灾区分布最为广泛，受开挖损伤影响最为普遍。本文以汶川地震灾区为研究背景，利用野外调查、数值模拟和室内物理模型试验相结合的手段，对地震荷载作用下层状岩质开挖损伤斜坡的变形破坏机理进行了研究。通过野外调查对开挖层状岩质斜坡的结构进行了划分，分析了其变形破坏形式。利用数值模拟手段，揭示了不同开挖坡高、开挖坡角以及不同层状结构面对斜坡地震动力响应的影响。利用室内物理模型试验手段，重现了不同结构类型斜坡的变形破坏过程，揭示了其在地震荷载作用下的破坏规律。可为开挖层状岩质斜坡的灾害治理及抗震设计提供参考。论文的主要研究内容与结论如下： （1）对开挖层状岩质斜坡的结构类型进行了划分，分析了其变形破坏形式，总结了与开挖层状岩质斜坡结构类型相对应的地震滑坡类型，为层状岩质开挖损伤斜坡的宏观稳定性判断提供了依据。其中开挖顺层中-缓倾斜坡和开挖反倾二元结构斜坡主要发生整体滑动破坏，滑坡类型以整体滑动型为主。开挖顺层陡倾斜坡和开挖反倾裸露斜坡变形破坏兼具崩塌、滑动两种形式，滑坡类型以崩滑型为主。 （2）分析了反倾和顺层两种结构面对斜坡地震动力响应的影响，提高了对地震荷载作用下不同结构层状斜坡的稳定性差异的认识。顺层、均质和反倾斜坡的动位移、动应力和动加速度响应整体分布一致。但是以层面为界，顺层和反倾均出现不连续现象。顺层斜坡的地震动力响应总是大于反倾斜坡，这种地震动力响应特征，与顺层斜坡稳定性最差，而反倾斜坡稳定性较好相一致。 （3）分析了静态条件下开挖坡高和坡角对斜坡应力分布的影响。随着开挖坡角和开挖坡高的增大，斜坡坡脚的应力集中越来越显著，开挖损伤严重破坏了斜坡的初始应力平衡。 （4）分析了开挖坡高和开挖坡角对斜坡地震动力响应的影响，提高了对开挖损伤斜坡在地震荷载作用下的响应特征的认识，为解释其变形破坏特征提供了理论依据。随着开挖坡高的增大，斜坡的水平动位移、动应力和动加速度响应逐渐减小，而竖向动位移、动应力和动加速度响应逐渐增大。随着开挖坡角的增大，斜坡的地震动应力、动位移和动加速度响应都增大，对斜坡的稳定性不利。进一步证实了斜坡开挖过程中放缓坡度的必要性。同时表明，放缓坡度是提高斜坡结构抗震性能的重要措施。 （5）利用室内物理模型试验的手段，重现了各种结构类型开挖层状岩质斜坡的变形破坏过程。 顺层开挖中-缓倾角斜坡在地震荷载作用下的变形破坏过程为三个阶段：地震初始阶段（开挖不连续层面微剪出及开挖坡顶形成大量裂缝）～开挖坡顶浅表崩塌阶段～整体滑动阶段。 顺层陡倾角开挖斜坡在地震荷载作用下的变形破坏过程为四个阶段：地震初始阶段（开挖损伤岩层沿层面微小滑动，坡脚应力剧增）～开挖岩层坡脚溃曲阶段～全面下滑阶段～岩层下滑受阻倾倒阶段。 基岩裸露型反倾开挖斜坡在地震荷载作用下的变形破坏过程为四个阶段：地震初始阶段（开挖坡顶裂缝产生）～开挖坡顶浅表崩塌阶段～开挖损伤岩层倾倒阶段～撞击碎裂-滑动阶段。 二元结构反倾开挖斜坡在地震荷载作用下的变形破坏过程为三个阶段：地震初始阶段（浅表覆盖层与基岩接触面逐渐贯通）～浅表覆盖层滑动启动阶段～浅表覆盖层全面滑动及基岩牵引-倾倒阶段。 （6）利用野外调查、数值模拟和室内物理模型试验相结合的手段分析了开挖对地震荷载作用下斜坡变形破坏的影响，半定量的证明了开挖是影响斜坡变形破坏的重要因素。汶川地震灾区的野外调查结果表明，开挖损伤斜坡成为地震山地灾害的集中爆发区。开挖损伤斜坡地震动力响应的特征表明，开挖损伤加大了斜坡的地震动力响应。而典型实例数值分析以及室内物理模型试验的定量观测表明，开挖后斜坡变形破坏加剧。 |
| 英文摘要 | A lot of mountain hazards triggered by Wenchuan earthquake，and excavation damage slope becoming mountain hazards outbreak area. Layered rocky slope distribution by most widely in wenchuan earthquake disaster area, and affected by the excavation damage most common. The deformation and failure mechanism of the excavation damage layered rocky slopes is rereached by field investigation, numerical simulation and indoor physical model test. Provide reference for excavation layered rocky slope disaster and aseismic design.The main research results and conclusions are as follows: （1）The excavation layered rocky slope structure are classified 4 categories. And its deformation forms and corresponding landslide types are analysed. The result provide the basis to judge the macro stability of layered rock excavation damage slope.The classified of slope structure as follows: Excavation in appropraite bedding slope, excavation bedding steep slope, inverse pour bare slopes and inverse pour binary structure. The deformation forms of excavation in appropraite bedding slope and inverse pour binary structure mainly whole-sliding and corresponding whole-sliding landslide. Collapse-sliding is the mainly deformation forms of excavation bedding steep slope and inverse pour bare slopes, and corresponding collapse-sliding landslide. （2）The effect of the inverse pour and bedding structure surface on seismic dynamic response are analyzed. It’s improved the cognition that stability differences of different structure layer slope under seismic load.The dynamic displacement, dynamic stress and dynamic acceleration response of bedding slope, homogeneous and the inverse pour slope overall consistent in distribution. But is bounded by level, bedding and reverse poured all appear discontinuous phenomenon. Bedding slope dynamic response is always greater than inverse pour slope, these earthquake response characteristics consistent with stability of inverse pour slope than bedding slope stability. （3）The effects of the excavation slope height and the excavation slope angle on slopes under the static condition are analyzed. With excavation slope height and the excavation slope angle increases, the stress concentration of the slope toe more and more remarkable. The slopes initial stress balance badly damaged by excavation. （4）The effects of the excavation slope height and the excavation slope angle on slopes seismic dynamic response are analyzed. It’s improved the cognition that the response characteristics of excavation damage slope under seismic load, and the results provides theoretical basis to explain the deformation and failure feature of slope under excavation damage condition. The level dynamic displacement, dynamic stress and dynamic acceleration are decreasing with the increase excavation slope height, while the vertical dynamic displacement, dynamic stress and acceleration responses gradually increasing. Along with the increase of excavation slope angle, slope dynamic displacement, stress and acceleration response are increase. It’s adverse to the stability of the slope. Further confirmed that the necessity of slow slope in excavation process, also show that slow slope is the important measure to improve slope structural anti-seismic performance. （5）The deformation and failure process of different types slope structure is recreated by using indoor test method. （6）Effects of excavation on slopes deformation and failure under the action of seismic load are analyzed by field investigation, numerical simulation and indoor physical model test. The excavation is the unfavorable factor affecting slope stability is evidenced semi-quantitative. |
| 语种 | 中文 |
| 公开日期 | 2013-01-30 |
| 源URL | [http://192.168.143.20:8080/handle/131551/4865]  |
| 专题 | 成都山地灾害与环境研究所_山地灾害与地表过程重点实验室 |
| 推荐引用方式 GB/T 7714 | 阿发友. 地震荷载作用下层状岩质开挖损伤斜坡的变形破坏机理[D]. 北京. 中国科学院研究生院. 2011. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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