基于模型试验的崩塌撞击碎裂地震动信号特征分析

    ANALYZING SEISMIC SIGNAL FEATURES OF ROCKFALL IMPACT FRAGMENTATION: INSIGHTS FROM MODEL TESTING

    • 摘要: 崩塌作为一种山区常见地质灾害类型,具有显著隐蔽性、突发性及灾难性特征,实时监测与动力学过程的量化分析较困难。地震动信号可间接反应出高位崩塌坡面撞击碎裂过程的地震动能强弱特征,进而反演崩塌运动过程。本文通过开展高位崩塌坡面撞击碎裂过程物理模型试验,采集了地震动信号,研究其与坠落高度、方量及碎裂程度的量化关系。结果表明:(1)随崩塌坠落高度或方量的增加,阿里亚斯强度越大,即撞击产生的地震动信号的能量越强。(2)堆积体最远运动距离与覆盖面积与阿里亚斯强度成正比关系,地震动信号能量越强,堆积体最远运动距离越大,覆盖面积越广。(3)崩塌碎裂度是影响堆积体最远运动距离与覆盖面积的关键指标,通过对比分析碎裂度、地震动信号能量及动力学参数之间的关系,得到阿里亚斯强度越大,崩塌碎裂度越大,同样运动距离越远,覆盖面积越大。上述研究可为山区高位崩塌灾害的监测预警提供一种新思路。

       

      Abstract: As a common geological disaster type in mountainous areas,rockfall has obvious hidden,sudden and catastrophic characteristics. So far it is difficult to monitor or analyze the impact fragmentation process in a real-time way. The ground motion signals can indirectly reflect the seismic kinetic energy characteristics of the impact fragmentation process of the high rockfall events,and then invert the rockfall movement process. In this paper,a physical model test is carried out to collect the ground motion signal and study the relationship between the signal and fall height,volume and fragmentation degree. The results show that: (1)With the increase of the fall height or square amount,the Arias intensity becomes greater,which is the energy of the ground motion signal generated by the impact. (2)The runout distance of the accumulation deposit and covered area is proportional to the Arias strength. The stronger the ground motion signal energy is,the greater the runout distance of the accumulation deposit and the wider the covered area. (3)The degree of rockfall fragmentation is a key index that affects the runout distance and covered area of the accumulation deposit. The relationship among fragmentation degree,the ground motion signal energy and dynamic parameters are comparative analysed. It can be concluded that the greater Arias intensity,as well as the degree of rockfall fragmentation,the runout distance,and the covered area. The research can provide a new approach for the monitoring and early warning of high-level rockfall disasters in mountainous areas.

       

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