Calculation Method of Overburden Damage Height Based on Fracture Mechanics Analysis of Soft and Hard Rock Layers

Table 9

Rock mechanical parameter measurements of overlying strata in Yuwu coal mine [37].

Rock formation name	Tensile strength (MPa)	Compressive strength (MPa)
K8 sandstone	6.56~8.71; 8.01	87.8~93.5; 91.3
Coarse sandstone	3.24~6.11; 5.12	46.7~59.8; 54.6
Medium sandstone	5.78~9.29; 7.63	80.1~100.9; 92.4
Fine sandstone	6.14~8.81; 7.34	76.5~99.6; 85.7
Siltstone	3.52~5.98; 5.24	50.4~65.8; 58.9
Sandy mudstone	3.63~6.14; 5.03	35.4~53.2; 43.6
Mudstone	1.04~1.14; 1.08	30.2~39.9; 36.4