虹吸排渗系统在尾矿坝降水工程中的应用

Application of siphonic drainage system in the dewatering engineering of tailing dam

为保证尾矿坝加高工程的顺利实施,采用虹吸排渗系统来降低坝体内部的浸润线高度。以马兰庄铁矿尾矿库为例,对尾矿库工程中虹吸排渗系统的组成和尾矿砂中虹吸井的施工方法进行了简要介绍。虹吸井设置在初期坝上游附近,相对下游高差为8m。虹吸井深12～16m,直径550mm,相邻井点的间距均为6m。虹吸管为DN57型PVC软管。现场完成了14口虹吸井,并进行了13组双井抽水试验和一组单井抽水试验。其结果表明,采用清水冲击钻进方法施工的虹吸井成井质量较好。虹吸井的涌水量可达147m3 d。虹吸系统在井内水深小于6 5m时可自动工作。监测结果表明,在虹吸系统投入使用后,坝体地下水位埋深普遍在坡面7m以下。虹吸系统自行启动性能较强,降水效果明显,完全可以适应加高工程的需要。

To ensure the heightening engineering of tailing dam to successfully carry through, siphonic drainage system was adopted to lower the phreatic line in the dam. Tailing pond of Malanzhuang Iron Ore Mine was as the example to introduce the constitute of the siphonic drainage system and the construction technique of siphonic well in tailing sand. The siphonic wells are placed at upstream of primary dam with the height difference of 8 m to downstream. The depth of siphonic well is 12 m～16 m, the space between both close well is 6 m, and the diameter of siphonic well is 550 mm. The siphonic tube is made of PVC whose diameter is 57 mm. 14 wells , 13 pumping tests with two wells and 1 with single well have been finished. The results of pumping test in situ show that the quality of drilling wells by means of water-percussion is creditable. The stream capacity of siphonic well is about 147m^3/d. The system can automatically work when the water level is below 6.5 m. The monitoring results show that after the siphonic drainage system started to work, the water level in the dam was obviously lowered to 7m. The performance of the above system can run automatically with obvious dewatering effect and absolutely fit to the heightening engineering.