Insights into Unloading Relaxation Mechanism of Columnar Jointed Basalt at the Baihetan Left Dam Foundation

Table 1

Unloading relaxation characteristics of columnar jointed basalt on left dam foundation.

Description	Average value of wave velocity in relaxation zone (m/s)	Average value of wave velocity in unrelaxed zone (m/s)	Average value of relaxation depth (m)	Lithology	Location
A1	3150	5186	0.8	III-1	Upstream
A2	3284	5249	0.4	III-1	Upstream
B1	2844	4962	2.9	III-2	Middle stream
C1	2874	4946	3.0	III-2	Middle stream
B2	2988	5070	2.7	III-1	Downstream
C2	2980	5045	2.4	III-1	Downstream