Analysis on Subsidence Law of Bedrock and Ultrathick Loose Layer Caused by Coal Mining

Table 1

Parameters of strata.

Strata	Thickness/m	Density/kg·m^-3	Uniaxial compressive strength/MPa	Tensile strength/MPa	Elasticity modulus/GPa	Cohesion/MPa	Internal friction angle/°	Poisson ratio
Loose layer	724.7	2210
Fine sandstone	1.6	2340	76.8	6.9	19.6	19.28	36	0.26
Mudstone	75.09	2470	40.8	5.7	6.56	11.36	30	0.32
Fine sandstone	3.87	2340	76.8	6.9	19.6	19.28	36	0.26
Mudstone	5.98	2470	40.8	5.7	6.56	11.36	30	0.32
Fine sandstone	15.15	2340	76.8	6.9	19.6	19.28	36	0.26
Mudstone	8.15	2470	40.8	5.7	6.56	11.36	30	0.32
Fine sandstone	16.18	2340	76.8	6.9	19.6	19.28	36	0.26
Coal 3	4.04	1350	15.8	1.8	3.52	4.82	28	0.33
Mudstone	4.01	2470	40.8	5.7	6.56	11.36	30	0.32
Fine sandstone	10.7	2340	76.8	6.9	19.6	19.28	36	0.26