泥石流窗口坝闭塞类型及其临界条件实验研究

Experimental Study on Blocked Types and Critical Conditions of Window-frame Dam Preventing Debris Flow

窗口坝是泥石流拦挡坝常用类型之一,其设计仍以设计者的经验和水工设计方法为主,尚缺乏理论依据和技术支持。窗口坝设计时如何选择合理的开口尺寸、数量,使其达到良好的拦砂效果,是目前急需解决的技术问题。通过实验对窗口坝拦截不同性质泥石流时的闭塞类型及其临界条件进行了探讨,发现窗口坝拦截稀性、过渡性泥石流时表现为全闭塞、部分闭塞和不闭塞3种类型:当F≤0.95时,窗口坝全闭塞;当0.95<F≤1.5时,窗口坝部分闭塞;当F>1.5时,窗口坝不闭塞。窗口坝拦截粘性泥石流时表现为全闭塞和部分闭塞2种类型:当F≤2.7时,窗口坝全闭塞;当F>2.7时,窗口坝部分闭塞。

The window-frame dam is one of the common countermeasures in debris flow preven- ting engineering. However, at the moment, the design of window-frame dam is mostly based on designer＇s experience and hydraulic design methods, theoretical and technical guides are still lac- king. How to select reasonable opening size and quantity are the technical problems which ur- gently need to be resolved. In order to perfect the design methods, a series of experiments were conducted to research the blocked types and critical conditions of window-frame dam. According to the experiment results, there are three kinds of blocked types of window-frame dam for diluted debris flow and transient debris flow, that is total-blocked type, part-blocked type and opening type：WhenF≤0. 95, window-frame dam is total-blocked; when 0. 95〈F≤1. 5, dam is part- blocked; while F≤1. 5, dam is opening type. And there are two kinds of blocked types of win- dow-frame dam for viscous debris flow, that is total-blocked type, part-blocked type：when F≤2.7, the window-frame dam is total-blocked; when F〉2.7, dam is part-blocked.