Evaluation of Water Retention Capacity of Bulkheads in Underground Coal Mines

Table 10

Parameters to calculate hydraulic gradient of the surrounding rocks in Sanhejian coal mine.

Location of bulkhead	Transport roadway	Material roadway
Length of wall L (m)	24	24
Height H (m)	760	735
Embedded depth E (m)	2	2
Permeability k (um^2)	0.30	0.30
Rock mass integrity coefficient KV	0.35	0.35
Penetration coefficient of water diversion channel in surrounding rock m	10	10
Critical hydraulic gradient Icr	17.70	17.12
Stable hydraulic gradient Is	27.14	26.25
Icr/Is	0.65	0.65