Evaluation of Water Retention Capacity of Bulkheads in Underground Coal Mines

Table 9

Calculated I_cr/I_s ratio and observed water flow rate (leakage) around bulkheads in different mines in China.

Trial no.	Mine site	Critical hydraulic gradient Icr	Steady state hydraulic gradient Is	Icr/Is	Water flow (leakage) rate
1	Yangzhuang mine ②③④	26.88	7.51	3.58	0 m^3/h
2	Xiazhuang	31.64	9.94	3.18	0 m^3/h
3	Qixi mine ②③④	16.67	6.84	2.44	0 m^3/h
4	Gequan mine	30.13	13.61	2.21	0 m^3/h
5	Hemei 10 mine	26.32	13.58	1.94	0 m^3/h
6	Qixi mine ①	20.00	10.62	1.88	0 m^3/h
7	Taoyuan mine	50.77	28.09	1.81	0 m^3/h
8	Yangzhuang mine ①	25.91	15.45	1.68	0 m^3/h
9	Quanshang mine	33.33	21.16	1.58	5.0 m^3/h
10	Qidong mine conveyor roadway	49.44	43.73	1.13	2.0 m^3/h
11	Qidong mine caved roadway	53.35	57.34	0.93	2.6 m^3/h
12	Dongjiahe mine	9.08	13.16	0.69	1.5 m^3/h
13	Dongzhuang mine	38.61	63.59	0.61	2.0 m^3/h