Study on Numerical Simulation Test of Mining Surface Subsidence Law under Ultrathick Loose Layer

Table 2

Input parameters obtained by trials and errors.

Name	Elastic modulus/GPa	Tensile strength/MPa	Cohesive strength/MPa	Internal friction angle/(°)	Friction coefficient	Normal (tangential) stiffness ratio
Fine sandstone	6.2	2.0	9.55	7	0.123	1.0
Mudstone	2.5	1.65	5.05	5	0.087	1.0
Coal seam	0.9	0.51	2.45	3	0.052	1.0