牛眠沟地震滑坡碎屑化全过程离散元模拟  

Simulation of the whole process of Niumiangou creek rock avalanche triggered by the earthquake using a distinct element method

作　　者：毕钰璋 付跃升[1] 何思明[2,3] 吴永[2,3] 

机构地区：[1]福州大学紫金矿业学院,福建福州350116 [2]中国科学院山地灾害与地表过程重点实验室,四川成都610041 [3]中国科学院水利部成都山地灾害与环境研究所,四川成都610041

出　　处：《中国地质灾害与防治学报》2015年第3期17-25,共9页The Chinese Journal of Geological Hazard and Control

基　　金：国家自然科学基金面上项目"大型地震滑坡碎屑化动力学机理与定量风险研究"(41272346);国家自然科学基金"岩质贯通滑面的微观接触摩擦特性研究"(41202258);"十二五"国家科技支撑计划课题"龙门山地震带崩塌滑坡泥石流灾害防治技术研究与示范"(2011BAK12B03)

摘　　要：2008年5月12日,发生在中国四川省的Ms 8.0级地震触发了牛眠沟特大滑坡事故,并引发了高速远程滑坡碎屑流。其滑坡碎屑流横向移动距离约3.0 km,滑坡总体积约7.5×106m3。由于地震滑坡碎屑化过程的复杂性,国内外对此项灾害的研究成果较少。又由于其动力过程的规模巨大,室内试验无法还原灾害的动力全过程。因此本文以牛眠沟地震滑坡引发的碎屑流为研究对象,对其动力全过程进行了详细的研究。本文采用了2D离散元模型对牛眠沟滑坡进行了数值模拟,数值模型的建立是在二维颗粒单元粘结的基础上完成的,此模型还原了牛眠沟地震滑坡碎屑化动力全过程,对各过程的模拟结果进行了详尽的分析。并且揭示了不同的摩擦系数情况下滑坡特性,对其滑移范围和滑移规律进行了分析和讨论。结果显示,启动及碎屑化阶段的破坏程度受自由面影响较大,地震引发的动能则是影响凌空飞行阶段和堆积结果的主要原因,并推算出实地摩擦系数在0.2~0.3。其研究成果对今后类似的研究有一定的参考价值,并对致灾范围预测具有指导意义。The Niumiangou Creek rock avalanche was triggered by an Ms 8. 0 earthquake that happened on 12 May 2008 in the Sichuan Province,China. The rock avalanche traveled a horizontal distance of 3. 0 km with more than7. 5 × 10^6m^3. But because of its complexity,there is few theory about its dynamics. As its enormous of its scale,the laboratory test can ＇t show its whole process of dynamics. The paper primarily studied dynamics of Niumiangou Creek rock avalanche triggered by earthquake. The kinematic behavior of rock avalanche is simulated using a 2D discrete element model through the case of Niumiangou Creek rock avalanche. The numerical model used in this work is composed of 2D discs bonded together,and it reveals the whole process of dynamics of Niumiangou Creek rock avalanche. The detailed analysis was carried out in this paper,and the modeling thus indicates that a different friction coefficient is required to account for the actuallandslide characteristics,and simulate the whole process of its dynamics. The runout behaviors and laws are analyzed and some useful conclusions are drawn. The result show that the extent of damage in the failing and disintegrating segment is mainly affected by free face,the kinetic triggered by earthquake is the main reason that caused the flying result and the flowing result,and the friction coefficient was inferred as 0. 2 ~ 0. 3. The conclusions have some practical value for future similar research,and they have directive significance and application value for destroying area forecast of rock avalanche.

关 键 词：碎屑流 2D离散元 全过程 岩石边坡 颗粒流 

分 类 号：P642.22[天文地球—工程地质学]