Identification and Assessment of Subway Construction Risk: An Integration of AHP and Experts Grading Method

Table 5

Environmental impact level standard.

Grade	A	B	C	D	E
Scope and degree of influence	The scope is very large, and the surrounding ecological environment is seriously polluted or damaged.	It involves a large range, and the surrounding ecological environment is heavily polluted or damaged.	It involves a large range, and the ecological environment in the region is polluted or damaged.	The area involved is small, and the ecological environment in the adjacent area is slightly polluted or damaged.	The scope involved is very small, and there is a small amount of pollution or damage to the construction environment.