地震下陡崖层状危岩群体崩塌规律研究

发布时间：2018-08-31 08:33

【摘要】：本文利用离散元数值模拟的相关知识对影响层状危岩群体崩塌的影响因素进行了定量分析研究,得到了危岩群体崩塌的破坏模式和破坏特征,并总结了地震作用下陡崖层状危岩崩塌群体破坏规律以及危岩崩塌的前兆特征,最终完成了以下工作:1.将陡崖层状危岩群体崩塌的影响因素概括地形地貌特征、地质特征、地震动三大因素,并细化分为危岩体赋存高度、危岩体高度、陡崖坡度、危岩体破碎程度、层面倾角、岩层厚度以及地震动振幅等7个条件。利用UDEC离散元软件建立陡崖层状危岩群体的数值模型,并使之在不同参数条件下发生崩塌破坏,记录下危岩体的崩塌过程和崩落块体的运动轨迹及横竖向位移,研究基于不同地形地貌、地质特征、地震波条件下的层状危岩群体崩塌的破坏形式和破坏规律。2.基于研究内容一,总结和分析陡崖层状危岩发生崩塌时基于时间节点的崩塌破坏点,提出基于崩落块体横竖向位移的“位移角”概念,以位移角曲线的突变转折点作为危岩体崩塌破坏的前兆特征,从而总结和分析出不同条件和参数值条件下的“临界位移角”作为破坏点,以得出不同地形地质特征及地震波大小情况下的崩塌前兆特征。3.引入AHP层次分析法来系统化、量化研究不同地形地貌、地质特征和地震波因素对陡崖层状危岩体崩塌的影响程度,选用单层次模型结构,将危岩体赋存高度、危岩体高度、陡崖坡度、危岩体破碎程度、层面倾角、岩层厚度以及地震动振幅等7个因素作为评价因素,在总结相关参考文献和上文所做的不同条件下的数值模拟结果的基础上,对各个因素的相对重要性进行专家打分,根据线性代数相关知识得到不同条件对危岩体崩塌的影响程度,为进一步研究破碎危岩区域地质灾害之崩塌性风险评估奠定基础。
[Abstract]:Based on the knowledge of discrete element numerical simulation, the factors influencing the collapse of layered dangerous rock group are quantitatively studied in this paper, and the failure mode and characteristics of collapse of dangerous rock group are obtained. And summarized the rock collapse group failure law and the precursor characteristics of dangerous rock collapse under the action of earthquake, and finally completed the following work: 1. The influencing factors of collapse of stratiform dangerous rock group on steep cliff are summarized as three major factors: topographic and geomorphologic characteristics, geological characteristics and ground motion, and are divided into three major factors: occurrence height of dangerous rock mass, steep slope degree, degree of fragmentation of dangerous rock mass, and plane dip angle. There are seven conditions, such as the thickness of rock layer and the amplitude of ground motion. UDEC discrete element software is used to establish the numerical model of rock mass in steep cliff stratiform and dangerous rock. The collapse process of dangerous rock mass and the movement track and vertical displacement of caving block are recorded under different parameters. Based on different topographical and geomorphological features and geological characteristics, the failure patterns and failure rules of stratiform rock mass collapse under seismic wave conditions are studied. Based on the research content 1, this paper summarizes and analyzes the collapse failure point based on time node in the collapse of stratiform dangerous rock of steep cliff, and puts forward the concept of displacement angle based on the horizontal and vertical displacement of caving block. Taking the abrupt turning point of displacement angle curve as the precursor of collapse and failure of dangerous rock mass, the critical displacement angle under different conditions and parameter values is summarized and analyzed as the failure point. In order to obtain different topographic and geological characteristics and seismic wave size of the collapse precursor characteristics. 3. AHP analytic hierarchy process (AHP) is introduced to systematize, quantificationally study the influence of different landforms, geological features and seismic wave factors on the collapse of precipitous layered dangerous rock mass. The single layer model structure is used to store the dangerous rock mass height and the dangerous rock mass height. The slope of steep cliff, the degree of fragmentation of dangerous rock mass, the angle of slope, the thickness of rock layer and the amplitude of ground motion are taken as evaluation factors. Based on summarizing the relevant references and the results of numerical simulation under different conditions made above, The relative importance of each factor is evaluated by experts, and the influence of different conditions on the collapse of dangerous rock mass is obtained according to the relevant knowledge of linear algebra, which lays a foundation for further study on the risk assessment of collapsibility of regional geological hazards of broken rock.
【学位授予单位】：南京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.21

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