喇嘛溪沟泥石流形成条件及易发性评价

Formation Conditions and Proneness Evaluation of Debris Flow at Lama Stream

雅安—泸沽高速公路途径汉源县境内文武坡喇嘛溪沟的昔格达地层,工程地质性质极差。该流域坡面受水长期冲刷,形成多条冲沟;沟道纵比降大,且侧壁松散固体物质丰富,侵蚀严重,在暴雨的诱发下有可能发生泥石流,直接对高速公路的修建与运营造成影响。在调查研究的基础上,分析了喇嘛溪沟泥石流形成的条件,对流速、冲击力、总量等进行了计算,并评价了该泥石流的易发性,结果表明:喇嘛溪沟泥石流的类型属于暴雨型稀性泥石流,相应设计概率下的暴发规模属小型,泥石流流量很小,基本以水土流失形式存在。建议采取一定的防治措施。

Ya＇an-Lugu Highway passes the Xigeda Strata at Lama Stream, Wenwu Slope, Hanyuan County, subject to adverse engineering geological properties. There are many gullies formed due to long-term water erosion on slope surface in this river basin. As a result of large vertical slope, loose sidewall, rich solid matters and serious erosion, debris flow is possible to arise when induced by rainstorm, affecting the highway construction and operation directly. Based on the surveys, the formation conditions of debris flow at Lama Stream were analyzed, the flow rate, impact force and total amount calculated, and the proneness of the debris flow evaluated. The results show that the debris flow at Lama Stream is stormy and watery so that under corresponding design probability, the outbreak scale is small with small flow rate and in the form of water and soil loss basically. Thus it is recommended to adopt some prevention and control measures.