细粒含量对泥石流启动影响的离心机模型试验

摘要

采用自主研发的离心机可视化试验装置,在坡度和降雨强度不变的条件下,配置6组不同细粒含量的坡体,进行降雨诱发泥石流离心机模型试验.通过分析坡体破坏形态、孔隙水压力变化、雨水迁移规律等,研究细粒含量对泥石流启动过程的影响.研究结果表明:泥石流启动存在临界细粒含量(约为15％),在临界细粒含量范围内,坡体表现为分层滑动破坏,10％细粒含量的泥石流启动时间最短;泥石流启动过程中坡内孔压逐渐上升至峰值后波浪状下降,随着细粒含量的增加,孔压曲线趋于平缓;细粒含量影响雨水的渗透速度和路径,这是影响坡体破坏形态和决定泥石流能否启动的直接原因.%Using the self-developed visualization test apparatus with constant slope and rainfall intensity and making six sets of slopes with different fine contents,centrifuge model tests on rainfall-induced debris flow were carried out.Through the analysis of slope failure patterns,the development of pore water pressure,moisture migration,and the influence of fine contents on the debris flow initiation process were studied.The test results indicate that there is a critical fine content(about15％)with the initiation of debris flow,the failure pattern of slopes is retrograded sliding when fine contents are blow the critical value,and the start time of debris flow with 10％ fine content is the shortest.During the initiation of debris flow,the pore pressure increases to the peak before it declines like a wave and the curve of pore pressure tends to be gentle with the increase of fine contents.Fine contents influence the infiltration rate and the path of water,which affects slope failure patterns,and determines whether the debris flow can start.