An Improved Model of Variable Fuzzy Sets with Normal Membership Function for Crane Safety Evaluation

Table 2

Level standard to surrounding rock stability.

Stability level	Rock mass quality C1	Uniaxial compressive strength C2 (MPa)	Integrality degree of rock mass C3	Groundwater percolation capacity C4 (L/(min·10 m))	Joint C5
Very good I	0–0.10	200–300	0.75–1.00	0–5	9-10
Good II	0.10–0.25	100–200	0.55–0.75	5–10	7–9
Fair III	0.25–0.40	50–100	0.30–0.55	10–25	4–7
Poor IV	0.40–0.60	25–50	0.15–0.30	25–125	2–4
Very poor V	0.6–1.00	0–25	0–0.15	125–250	0–2