水布垭工程建基岩体为一套软硬相间的层状沉积岩体，地层单元岩性组合复杂、剪切带与岩溶均较发育，如何进行工程岩体质量分级是一大难题。实际工作过程中，完全套用国标《工程岩体分级标准》（GB50218-94）尚不足以解决问题，为此在大量岩石物理力学试验成果及工程经验的基础上，结合水布垭工程岩性组合特征及主要控制因子，对本工程岩体质量进行了分级，并以此作为设计及洞室支护的依据。

 The rock mass of foundation of Shuibuya Project is a type of stratified sedimentation rock mass composed of interbedded stratum by weak layers and hard layers. For the complexly lithologic composition of stratum unit, well developed shear bands and karst, so it is a difficult issue how to carry out engineering classification of rock mass. In practical engineering, it is not satisfactory in resolving these problems entirely with National Standard for Engineering Classification of Rock Mass（GB50218-94）. Therefore, on the basis of abundant rock mechanical test results and engineering experience, and in combination with the composite characteristics and major controlling factors of Shuibuya Hyro-project, the quality classification of engineering rock mass is put into practice. And the results can provide evidence for engineering design and support of underground cave.