南门峡水库的坝址,位于中上寒武系中厚层状结晶灰岩和鲕状灰岩之上,河床复盖层厚度12～19米。坝区溶洞和溶蚀裂隙主要受纵向张及张扭性结构面的控制,比较发育。在勘探时曾产生过掉钻0.54米的现象,经连通试验测得地下水流速为0.18米/秒。在斜心墙基坑开 The dam site of the Nanmenxia Reservoir is located above the middle-upper Cambrian middle-graded crystalline limestone and oolitic limestone with a bed thickness of 12 to 19 meters. Dam cavities and dissolution fractures are mainly controlled by longitudinal sheets and tensional structural planes, and are relatively developed. During the exploration, there was a phenomenon of drilling 0.54 meters off the ground and the groundwater flow rate was 0.18 m / s as measured by the connectivity test. In the inclined heart wall foundation pit open