土石坝溃坝离心模型试验中水流控制与测量

Flow control and measurement in centrifugal model tests for earth-rock dam breaching

针对目前土石坝溃坝离心模型试验中存在的问题,研发了一套伺服水阀流量控制装置,显著提高了土石坝溃坝离心模型试验上游来水条件的控制精度,有效降低了模型试验结果的不确定性;建立了土石坝溃坝离心模型试验的水流相似准则;提出了一种采用内置于模型箱端板上的薄壁矩形量水堰测量土石坝溃坝离心模型试验中溃坝洪水流量过程的方法,并通过超重力场下的放水试验,证明了薄壁矩形量水堰的流量系数与离心机加速度无关,采用内置于模型箱端板上的薄壁矩形量水堰可准确测定土石坝溃坝离心模型试验中的溃坝洪水流量过程。

Aimed at the existing problems in the centrifugal model tests for earth-rock dam breaching,a set of servo water valve flow control device was developed. The control precision of upstream inflow condition was improved significantly after the adoption of the device,therefore,the uncertainty of the results of centrifugal model test for earth-rock dam breaching was effectively reduced. In addition,the similarity criterion of water flow in the centrifugal model tests for earth-rock dam breaching is established. Meanwhile,a measuring method utilizing a thin-walled rectangular water weir which was placed into the end plate of the model box is developed to measure the discharge hydrograph of dam breach in the centrifugal model tests.Furthermore,based on the outflow tests under the high gravity field,the conclusion can be drawn that theflow coefficient of the thin-walled rectangular water weir has no connection with the centrifugal acceleration, so the measurement method can give the accurate breach flow discharge hydrograph for centrifugal model tests.