青海加吾矿区玛日当沟泥石流启动机理研究

STARTING MECHANISM OF DEBRIS FLOW AT MARIDANG GULLY IN JIAWU GOLD MINE IN QINGHAI-TIBETAN PLATEAU

加吾金矿地处青藏高原区内柴达木盆地东缘区的青海南山微造山带内,为保障该区矿产资源勘查及开采工作的顺利进行,有效预防矿区内泥石流等突发性地质灾害的发生,本文通过开展矿区泥石流灾害详查工作,尤其是针对矿区重点工作区玛日当沟流域进行了系统的调查,建立对该流域泥石流灾害发育背景的充分认识。在此基础上,依据费祥俊等(2004)关于含有细颗粒水石流启动条件的研究成果以及青海省同德县气象观测资料,对玛日当沟泥石流启动机理作了系统研究。结果表明,加吾矿区所在区域上泥石流发生的临界雨量值为25.7mm;矿区玛日当沟具有暴发泥石流灾害的有利地形、物源及水动力条件;该流域泥石流属典型沟谷型稀性泥石流或水石流,且具有如下规律特征,即满足流体流速Uw≥5.35m·s-1,容重γc≤1.511t·m^(-3)。

Jiawu gold mine is located in Qinghai Nanshan micro orogenic belt in the east margin of Qaidam Basin, Qinghai-Tibetan Plateau area. The objectives of this work is to ensure the progress of the mineral exploration and mining and to prevent the occurrence effectively of the sudden geological disaster, such as debris flow within the area. A full awareness of the background of the sudden debris flows is established by conducting a detailed investigation of the debris flow, especially the systematically investigation of the Maridang gully river basin, where is the key work area of the mining area. Based on this, we study the starting mechanism of Maridang gully debris flow systematically according to the research achievement of Fei et al.（2004） . It was about the starting conditions of debris flow containing fine particles and the meteorological observation data in Tongde county, Qinghai province.The results show that the critical rainfall value of debris flow in Jiawu mining area, Maridang gully, has favorable conditions of the sudden debris flow. The conditions include terrain, source and water power. The debris flows in this area belong to the typical diluted debris flows, or water stone debris flows. They have the following characters： fluid velocity Uw≥5. 35m·s -1 and unit weight γ≤1.511t＊m 3.