Case Study: In Situ Experimental Investigation on Overburden Consolidation Grouting for Columnar Jointed Basalt Dam Foundation

Table 1

Characteristics of columnar basalt in the dam site area of the Baihetan hydropower station.

Category	Column length (m)	Column diameter (cm)	Rock fragmentation (cm)	Distribution	Notes
Type І	2.0~3.0	13~25	5	P2β3^2, P2β3^3
Type II	0.5~2.0	25~50	10	P2β3^2, P2β6^1, P2β7^1, P2β8^2
Type III	1.5~5.0	50~250	—	P2β2^2, P2β2^3, P2β4^1	Incomplete cutting