摘要
2013年4月20日四川省芦山县发生Ms7.0级强烈地震,诱发芦山县、天全县、宝兴县等多个县区2500多处崩塌、落石、滑坡、泥石流等次生灾害,但规模较小。天全县老杨乡汤家沟滑坡-碎屑流是此次地震诱发的最大一处滑坡,在地震作用下约有53万m^3的岩体自滑源区高速滑出。因剪出口下方山脊的阻挡作用滑体沿左右两侧发生分叉,此后分别沿春尖窝沟和干沟头沟高速运动,滑行约340 m和440 m后与各自沟谷侧壁发生撞击、爬坡解体为碎屑流,碰撞转向后继续向下滑行,总滑行距离约1.6 km,高程差约480 m。尽管关于芦山地震滑坡的研究很多,但对滑坡全过程动态模拟的研究较少。本文通过滑坡现场调查,解析了汤家沟滑坡的基本运动特征和滑体运动过程中发生的碰撞、铲刮、堆积等现象,并基于DAN3D动力分析软件,采用Friction-Voellmy复合模型反演了汤家沟滑坡运动全过程,得到了滑体的堆积、速度分布以及铲刮等特征。
On April 20,2013,a catastrophic rock avalanche was triggered by the Lushan earthquake in Sichuan Province,China. The rock avalanche motivated 530 000 m^3 of sandstone from the source area. After detaching from its source area,the slide mass ran down rapidly along the direction of 130° and the displaced materials were divided into two streams as a result of blockages of a small ridge at an elevation of 1480 m. The two debris streams flowed along two valleys after colliding with the ridge. The left part of the displaced materials travelled a distance of 340 m along the direction of 156°,impacting the left side of the Chunjianwo valley and ran up to the side slope at a maximum run-up height of 35 m. A minor portion of the materials flowed upstream,whereas most of the materials continued to flow downstream and finally converged into the right part of the displaced materials at an elevation of1200 m. The right part of the displaced materials travelled a distance of 440 m along the direction of 104°. The debris superelevated on the right side of the Gangoutou Valley with a height of 15 m,then diverted at an angle of35° along the valley floor and finally ceased at the Tangjia valley at an elevation of 1160 m. The displaced materials travelled 1,600 m with a descent of 480 m,and the final volume was accumulated to be approximately 1000 000m^3.The basic pattern of this rock avalanche was concluded by a detailed field investigation. It revealed that the rock avalanche resulted in one superelevation in the Gangoutou Valley and a run-up in the Chunjianwo Valley. To understand the post-failure behavior of the rock avalanche,a numerical model（ DAN-3D） was used to simulate the landslide propagation. By means of trial and error method,a combination of Frictional model and Voellmy model convinced of the best performance in simulating the rock avalanche propagation according to in site survey of runout,distribution and thickness of the final deposit. The results of simulation suggested that the rock avalanche had a duration of about 160 s and a maximum velocity of 30 m/s.
作者
夏式伟
郑昭炀
袁小一
邢爱国
XIA Shiwei ZHENG Zhaoyang YUAN Xiaoyi XING Aiguo(Department of Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, Chin)
出处
《山地学报》
CSCD
北大核心
2017年第4期527-534,共8页
Mountain Research
基金
国家自然科学基金重点项目(41530639)~~
