Karst Water Pressure’s Varying Rule and Its Response to Overlying Strata Movement in Coal Mine

Table 1

Material ratio of each rock stratum.

Lithology	Depth of stratum (m)	Proportion (sand : gypsum : lime)	Thickness (cm)	Stratified weight (kg)	Stratified number	Sand (kg)	Gypsum (kg)	Lime (kg)	Water (kg)
Sandstone	6.3	7 : 0.3 : 0.7	3	38.59	3	33.77	1.45	3.38	3.22
Siltstone	4.9	7 : 0.2 : 0.8	4	29.56	2	25.87	2.96	0.74	2.46
Fine sandstone	5.6	7 : 0.8 : 0.2	4	30.72	2	26.88	1.15	2.69	2.56
Sandstone	7	7 : 0.3 : 0.7	3	33.98	3	29.73	1.27	2.97	2.83
#5 coal seam	2.1	6 : 0.3 : 0.7	3	37.44	1	32.09	1.6	3.74	3.12
Sandstone	12.6	7 : 0.3 : 0.7	3	34.42	6	30.99	1.33	3.1	2.87