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

Table 3

Joints mechanical parameters.

Stratum name	Normal stiffness (GPa)	Tangential stiffness (GPa)	Cohesion (MPa)	Tensile strength (MPa)	Internal friction angle (°)	Dilatancy angle (°)
Overlying strata	5.3	2.50	1.9	0.50	25	2
Fine sandstone	5.2	2.38	1.26	0.39	18	2
Siltstone	5.1	2.40	1.30	0.47	20	2
Sandy mudstone	2.6	1.70	1.20	0.5	15	1
Mudstone	2.5	1.50	1.36	0.39	18	2
Coal seam 11-2	2.0	1.30	1.10	0.10	10	1
Mudstone	2.7	1.30	1.21	0.50	15	1
Carbonaceous mudstone	2.3	1.40	1.30	0.60	14	1
Underlying strata	5.4	2.50	1.76	0.50	20	2