岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
10期
2909-2926
,共18页
朱圻%程谦恭%王玉峰%车琪%侯文学%李炜
硃圻%程謙恭%王玉峰%車琪%侯文學%李煒
주기%정겸공%왕옥봉%차기%후문학%리위
沟谷多级折射%高速远程滑坡%三维模型%动力学分析%冲击气浪
溝穀多級摺射%高速遠程滑坡%三維模型%動力學分析%遲擊氣浪
구곡다급절사%고속원정활파%삼유모형%동역학분석%충격기랑
multi-deflected channel%rock avalanche%three-dimensional model%dynamic analysis%airblast
为研究沟谷多级折射高速远程滑坡超前冲击气浪的特征,以牛圈沟滑坡三维地形形态为原型,采用 CFD软件,引入Voellmy准则定义运动阻力,在反演碎屑流运动全过程的同时,对其冲击气浪的流场特征进行了数值模拟,分析其形成的动力学机制。结果表明:(1)牛圈沟滑坡从启动到停止历时为119 s,最大速度出现在滑体内部靠近前缘处,峰值分别为14 s的52 m/s、27 s的55 m/s和50 s的49 m/s。(2)气浪速度的最大值50 s时为38 m/s,其压强的最大值达657 Pa,相当于11级暴风。(3)当碎屑流前方出现高大的障壁时,来不及扩散的高压气流产生极为明显的压强梯度;当其前方遇跌坎或翻越山脊冲向山坡下方在其速度瞬间增大的同时,强烈压缩前方空气并导致其压强值局部出现陡增。
為研究溝穀多級摺射高速遠程滑坡超前遲擊氣浪的特徵,以牛圈溝滑坡三維地形形態為原型,採用 CFD軟件,引入Voellmy準則定義運動阻力,在反縯碎屑流運動全過程的同時,對其遲擊氣浪的流場特徵進行瞭數值模擬,分析其形成的動力學機製。結果錶明:(1)牛圈溝滑坡從啟動到停止歷時為119 s,最大速度齣現在滑體內部靠近前緣處,峰值分彆為14 s的52 m/s、27 s的55 m/s和50 s的49 m/s。(2)氣浪速度的最大值50 s時為38 m/s,其壓彊的最大值達657 Pa,相噹于11級暴風。(3)噹碎屑流前方齣現高大的障壁時,來不及擴散的高壓氣流產生極為明顯的壓彊梯度;噹其前方遇跌坎或翻越山脊遲嚮山坡下方在其速度瞬間增大的同時,彊烈壓縮前方空氣併導緻其壓彊值跼部齣現陡增。
위연구구곡다급절사고속원정활파초전충격기랑적특정,이우권구활파삼유지형형태위원형,채용 CFD연건,인입Voellmy준칙정의운동조력,재반연쇄설류운동전과정적동시,대기충격기랑적류장특정진행료수치모의,분석기형성적동역학궤제。결과표명:(1)우권구활파종계동도정지력시위119 s,최대속도출현재활체내부고근전연처,봉치분별위14 s적52 m/s、27 s적55 m/s화50 s적49 m/s。(2)기랑속도적최대치50 s시위38 m/s,기압강적최대치체657 Pa,상당우11급폭풍。(3)당쇄설류전방출현고대적장벽시,래불급확산적고압기유산생겁위명현적압강제도;당기전방우질감혹번월산척충향산파하방재기속도순간증대적동시,강렬압축전방공기병도치기압강치국부출현두증。
In order to study the intensity and the variation law of the airblast induced during the high-speed motion of rock avalanche with multiple angle changes along its travelling path, a true three-dimensional model of the Niujuangou rock avalanche is studied with the software CFD by introducing the definition of resistance along traveling path under the law of Voellmy. The characteristic of the airblast flow field is simulated emphatically with the dynamic mechanism of the airblast discussed based on the back-analysis of the whole travelling process of the Niujuangou rock avalanche. The results show:(1) The whole travelling process of the sliding mass lasts 119 s, and the maximum speed at every moment appears in the part near the front zone of the sliding mass (except t=50 s, the maximum speed appears in the front zone of the sliding mass) with three ultimate values of 52 m/s at 14th second, 55 m/s at 27 th second, and 49 m/s at 50 th second, respectively. (2) The maximum velocity of the airblast appears at the 50th second with its value reaching 38 m/s. The maximum pressure of the airblast, 657 Pa, is generated at the moment the sliding mass bursts out the scarp, which is equivalent to the violent storm. The squeezing effect of the sliding mass on the air ahead is the most obvious when the sliding mass is moving fast and the leading height is higher. (3) The topography along the sliding path displays a large influence on the distribution of airblast pressure. During the high-speed motion of the sliding mass, an obvious gradient variation of air pressure is induced when an obstruction appears along its sliding path, resulting in a destructive effect. When the sliding mass rushes down a scarp or ridge, the velocity of sliding mass will increase rapidly with a negative pressure generated inside of the sliding mass because of weightlessness, meanwhile, a sharply increase of the air pressure will also appear at some locations distributed ahead of the sliding mass due to the intensive compression induced by the sliding mass.