一、任务的提出和攻关目标我国西南地区河流可开发的水能资源十分丰富,但这些河流的河谷中都分布有不同深度的覆盖层,其中六、七十米以上的屡见不鲜。这些覆盖层的分布规律性差,结构和级配变化很大,常有粒径20～30cm的漂卵石,甚至1m I. Tasks Proposed and Targets for Targets The water resources that can be developed in the rivers in southwest China are very rich. However, there are layers of different depths in the valleys of these rivers, of which not less than sixty and seventy meters are commonplace. The distribution of these coatings is poor, the structure and grading vary greatly, often with a size of 20 ~ 30cm of the pebbles, and even 1m