Research on Plastic Zone Evolution Law of Surrounding Rock of Gob-Side Entry Retaining under Typical Roof Conditions in Deep Mine

Table 2

Rock mass mechanical properties.

Stratum name	Density (kg·m^−3)	Bulk modulus (GPa)	Shear modulus (GPa)	Cohesion (MPa)	Tensile strength (MPa)	Internal friction angle (°)	Dilatancyangle (°)
Overlying strata	2700	10.6	6.30	3.90	2.50	35	3
Fine sandstone	2724	7.87	3.38	3.26	2.19	28	3
Siltstone	2696	8.82	4.84	3.30	2.47	30	3
Sandy mudstone	2702	3.68	2.10	2.10	1.50	25	2
Mudstone	2678	3.35	2.10	1.80	1.60	24	2
Coal seam 11-2	1350	2.35	1.47	1.50	1.10	20	2
Mudstone	2781	2.65	2.20	1.90	1.46	34	2
Carbonaceous mudstone	2762	2.12	1.80	2.18	2.36	28	3
Underlying strata	2732	9.91	4.92	3.26	2.19	30	3
Filling body	2680	6.87	3.30	3.16	2.19	28	3