土石坝溃坝离心模型试验系统研制及应用

Development and application of centrifugal model test system for break of earth-rock dams

研制成功了一套土石坝离心模型溃坝试验系统,采用旋转接水环,确保了高加速度条件下溃坝试验过程中能持续提供足够的对坝体进行冲蚀的水量;采用先进的数据量测方法和图像采集系统能多角度捕捉和摄取土石坝的溃坝全过程,且该系统在高加速度和泥石流条件下能正常工作。利用该离心试验系统以32cm坝高的模型对最大坝高达32m的3种不同坝高均质土石坝进行了漫顶溃坝模型试验,研究了坝高对均质坝溃口发展规律和溃坝洪水流量过程的影响。结果发现:随着坝高的增加,溃口的纵向下切与溃口边坡的失稳坍塌速度明显加快,溃口流量过程线更为陡峭,峰值流量增大,且峰值流量出现时间更早,溃坝历时更短,因此,溃坝致灾后果将更为严重。

A centrifugal model test system is successfully developed for the study of the break of earth-rock dams. A rotational water-supply ring is fixed to ensure adequate water amount for simulating scouring flow against the dam body in the test under accelerated velocity conditions. Advanced data measuring methods and image capturing devices are used to capture in multiple directions the images of overall dam break processes under accelerated velocity and mud flow conditions. A model dam with height 32cm is used to simulate the overtopping failure of 3 homogeneous earth-rock dams. The mechanism of the dam break is clearly revealied, and the effect of dam height on the dam break and the hydrograph of flood flow is investigated. The results show that the higher the dam is, the greater the longitudinal downward cuting and the side slope collapse of the break are, the steeper the curve of the hydrograph of flood flow at the break is, the faster the peak flow discharge develops and the earlier the peak flow reaches its maximum amount, the shorter the duration of dam break becomes. As a result, the more serious the damage caused by the break will be.