( 3 ) ensemble character of structural planes as follows : in left dam abutment , meta basalt schistosity is main , and the structure is clockwise . low dip angle jointing did n ' t develop in rock mass ; in right dam abutment , rupture and jointing structural plane is main , and the structure is reversed . the structure was of obvious macroscopical slaty character ( 3 )通过对上述结构面的分析，得出其总体特征为：左坝肩以变玄武岩片理为主体，呈顺向结构，岩体内缓倾角节理极不发育；右坝肩主要为断裂及节理型结构面，呈反向结构，且具有明显的宏观板状结构特征，并发育有一定厚度的构造软岩带。
