Failure Mechanism Analysis and Support Design for Deep Composite Soft Rock Roadway: A Case Study of the Yangcheng Coal Mine in China

Table 2

Physical and mechanical parameters of surrounding rocks.

Serial number	Lithology	Natural specimens					Saturated specimens
		Bulk density; (KN·m^3)	Uniaxial compressive strength; (MPa)	Tensile strength; (MPa)	Poisson’s ratio	Elastic modulus; (GPa)	Uniaxial compressive strength; (MPa)	Softening coefficient
①	Siltstone	25.70	47.46	5.82	0.25	5.89	22.78	0.48
②	Fine sandstone	25.16	31.85	3.76	0.13	5.23	17.20	0.54
③	Medium-grained sandstone	24.61	30.14	4.49	0.18	5.23	22.00	0.73
④	Mudstone	24.65	24.13	1.63	0.11	3.10	—	—
⑤	Mudstone	25.75	23.05	2.22	0.10	4.30	6.45	0.28