Influence of Support Parameter and Excavation Methods on Statistical Distribution Characteristics of Surrounding Rock Pressure in Shallow-Buried Metro Tunnel

Table 3

Distribution characteristics of multiple joint parameters.

Rock mass type	Group number	Trace length (m)		Direction angle (°)		Depth (m)	Thickness of weathered layer (m)	Density
		Mean	Mean square deviation	Mean	Mean square deviation
Soft rock	1	6	0.7	0	5.5	6	5	0.15
	2	6	0.7	90	5.5
Hard rock	1	10	0.7	30	2.2			0.09
	2	10	0.7	150	2.2
Distribution form		Normal		Normal