岷江杂谷脑河跨过沟泥石流致灾机理及发展趋势

Analysis of disaster-causing mechanism and development trend of Kuaguo Gully debris flow in Zagunao valley of Minjiang River

跨过沟是暴发在岷江支流杂谷脑河的一次灾害性泥石流,给沟口处的居民和省道等基础设施造成了极大的破坏。有利的地形条件、丰富的物源储备、短时强降雨过程是跨过沟泥石流形成的条件。通过野外调查和室内试验,分析了跨过沟泥石流堆积物的颗粒组成,详细阐述了泥石流的冲淤及堆积特征,有利于进一步认识泥石流活动过程。根据野外调查及理论分析,计算了泥石流流体流速、流量、一次泥石流过程总量、泥石流体集体冲压力等动力学特征参数。判定跨过沟泥石流当前处于壮年期,并预测在强降雨条件或强震作用下可能发生更大规模的泥石流,淤积、冲毁沟道两侧房屋,甚至冲毁G213国道。

Kuaguo Gully debris flow is distributed in Zagunao Valley, a tributary of the Minjiang River, which has caused great losses to residents, provincial road and other infrastructures. Favorable topography conditions, abundant source reserves and short-time strong rainfall process are the conditions for the formation of the debris flow. Through field investigation and laboratory test, the particle composition of the debris flow were analyzed, the scour and deposition characteristics of debris flow were expounded in detail, which were helpful to further understanding the process of debris flow activity. Based on field investigation and theoretical analysis, the kinetic parameters of debris flow, such as flow velocity, flow rate, total amount of one-time debris flow and joint punching pressure of debris flow were calculated. It is determined that the Kuaguo Gully potential debris flow is currently in the development period, and predicted that a larger debris flow may occur under heavy rainfall or strong earthquakes, depositing and destroying the houses on both sides of the gully, and even the G213 State Road.