梳子坝淤砂形态特征试验研究

Experimental Study of Configuration of Intercepted Sediments by Comb Dam

通过室内水槽试验,探讨梳子坝淤砂的形态特征、淤砂长度和回淤坡度等,初步得到:(1)梳子坝在全闭塞时,淤砂形态与实体坝相似,在淤砂区的前部,淤砂高度大致等于坝体高度,在淤砂区的尾部,都有一个明显的陡坎;梳子坝在部分闭塞时,淤砂形态与不闭塞情况下淤砂形态相似,在淤砂区的前部,都有一个缓坡。不闭塞时形成的缓坡坡度稍大于部分闭塞时的缓坡坡度,但都明显小于水下休止角,表明梳子坝淤砂形态异于狭缝坝。(2)梳子坝淤砂长度与切口宽度有关,大致有随着切口宽度的增大而减短的趋势;切口密度和泥石流浓度对淤砂长度有影响,淤砂长度有大致随切口密度的增大而堆积长度减短的趋势。(3)在相同试验条件下,梳子坝回淤坡度与实体坝相比大致相近,波动范围很小;在相同的切口宽度条件下,切口密度对回淤坡度有一定的影响,同时证明沟床坡度和泥石流的物质级配、容重及规模对回淤坡度也有一定影响。

Through a series of flume experiments in the laboratory, the configuration of intercepted sediments by comb Dam, the length and slope of intercepted sediments are studied. The experimental results show that （1） The configuration of intercepted sediments by comb dam in total-blocking condition is similar to close-typed dam, and the height of intercepted sediments is almost equal to the height of comb dam near the foreside of dam body. At the tail of intercepted sediments, there is a steep slope. Under partblocking circumstance, the configuration is similar to that of opening, and there is a flat slope. The gradient of above two typed slopes is less than the internal friction angle of sediment; （2）The length of intercepted sediment is related to the slit width, and the length of intercepted sediments gradually decreases with the increase of slit width. Moreover, the slit density and debris flow concentration also affect the length of intercepted sediments. （3）Under the same experimental circumstances, the slope of intercepted sediments is similar to that of close-typed dam. With the same slit width, slit density affect the slope of intercepted sediments, flume gradient and scale of debris flow.