Evaluation of Rock Quality of Tunnel Wall Rock Based on Rough Set Theory and Unascertained Measurement Theory

Table 2

Classification criteria of the wall rock quality.

Grade	/MPa			W/[L·(min·10m]	θ/°
I	300~250	1.0~0.75	10~9	0~5	90~80
II	250~100	0.75~0.55	9~7	5~10	80~70
III	100~50	0.55~0.35	7~4	10~25	70~30
IV	50~25	0.35~0.15	4~2	25~125	30~10
V	25~1	0.15~0	2~0	125~300	10~0