在我国已建及在建的众多水电站中 ,采用地面式厂房的占绝大多数 ,采用地下厂房的也有一定比重 .但多数跨度都在 10～ 2 0ｍ之间 ,超过 2 0ｍ的为数不多 ,见表 1.在我国现正进行设计中的大跨度地下厂房还有一些 ,其中还有 2座跨度达到或超过 30ｍ ,一座是金沙江上的溪洛渡地下厂 Among the many hydropower stations that have been built and under construction in our country, the majority of ground-based factories are occupied and a certain proportion of underground factories are used, but most of the spans are between 10 and 20 meters, and over 20 meters are few, See Table 1. In our ongoing design of large-scale underground plant there are still some, of which there are two span of 30m or more, one on the Jinsha River Xiluodu underground plant