拦砂坝溢流口过流能力的大小是工程设计中的关键参数之一, 也是影响坝体安全的重要设计参数。结合泥石流过流特点, 分析推导了拦砂坝溢流口过流能力的参数计算式;在此基础上, 通过水槽实验建立了流量系数的经验公式。水槽实验表明, 溢流口过流能力随泥石流密度的增大而减小, 随沟道坡度的增大而增大, 随相对沟道宽度的增大而增大, 溢流口位置与沟道中心相对者大, 溢流口位置与沟道中心偏离者小。与现有计算方法相比, 所提通过理论推导和水槽实验建立起的拦砂坝溢流口过流能力参数计算式, 计算结果更为精确可靠, 可用于泥石流拦砂坝溢流口设计时的过流能力验算。

Discharge capacity of spillway of check dam is one of the key parameters in engineering design, it is also an important parameter affecting the safety of dam. Combining the discharge characteristics of debris flow, this article deduces the parameter formula of the discharge capacity of spillway of check dam, on the basis of that, empiric formula of discharge coefficient was established through the flume experiment. Flume experiment shows that the discharge capacity decreases with increase of debris flow density, increases with the increase of the channel slope and increase with the increase of the relative width of channel. The discharge capacity is strong when the position of spillway is on the line with the channel center and vice versa. Compared with the existing calculation method, this paper establishes formula for discharge capacity of spillway of check dam through the theoretical derivation and experiment, and the calculating result is more accurate and reliable, it can be used to calculate the discharge capacity of spillway in the check dam design.