四川泸沽铁矿大顶山矿区泥石流及其防治

大顶山支沟为一典型矿山泥石流沟。其根本原因是由于人为开矿弃渣所造成。流域面积1．8km^2，支沟长2km，沟床平均纵比降38．5％。松散固体物质储量在700万m^3以上，一旦遭遇强暴雨，极易形成泥石流。50年一遇设计频率的泥石流流量为364m^3／s，100年一遇设计频率的泥石流流量为419m^3／s。拦砂坝设计高度20m，最大基础埋深8m，高出原沟床面12m，可拦挡松散固体物质32万m^3。在设计频率下发生的泥石流，拦砂坝可以有效拦挡，不会对盐井沟3号拦砂坝造成直接危害。大顶山支沟泥石流防治工程的日常维护需按设计书的要求进行。此外，建议在汛期加强巡查，人工爆破沟内直径大干1m的石块，禁止在沟内及山坡上，特别是排土场上乱挖滥采矿石，以免加速废石矿渣向下游输送运移。同时继续实行封山育林，努力恢复植被覆盖，增大排土场人工堆石坡的稳定性。

Debris flow and its control in Dadingshan mining area of Lugu Iron Mine in Sichuan Province

Dadingshan debris flow is a typical mining debris flow. The cause for debris flow generation is the accumulation of abandoned mining slag. The drainage basin area of this gully is (1.8?km~2.) The channel length is 2?km. The average longitudinal gradient is 38.5%. The unconsolidated materials are over 7,000,000 m~3, in case of storm rain which will be easy to form debris flow. The designed frequencies with an interval of 50 years and 100 years for the debris flow in Dadingshan gully are 364?m~3/s and 419?m~3/s separately. Designed retaining dam is 20 m high, and is 12 m above surface of the gully bed, which may barricade loose materials of 320,000 m~3. and under the condition of designed frequency of debris flow occurrence, the dam may efficiently restrain debris flow. Thus the debris flow may not directly threaten the No.3 retaining dam in Yanjing gully. The prevention projects for the debris flow must be maintained normally according to the project design. Additionally, supervision during the rainy season is strongly suggested. It should be done to artificially bomb the stoneblocks with the diameters more than 1 m, and prohibit excessively mining and arbitrarily collecting the deposed ores in the gully and on the slopes, especially in the depositional area, so as to slow the debris transported downward. Meanwhile, it is suggestted to continue to forest and reforestation, so as to increase the stability of the depositional slopes.