Fuzzy Comprehensive Evaluation Method for Evaluating Stability of Loess Slopes

Table 6

Evaluation index stability grading standard.

Index	Evaluation level
	Stable	Relatively stable	Generally stable	Relatively unstable	Unstable
Slope height (m)	0–6	6–20	20–30	30–90	90–200
Slope angle (°)	0–15	15–30	30–45	45–60	60–90
Unit weight (kN/m^3)	18–30	17–18	16–17	15–16	0–15
Cohesion (kPa)	55–100	40–55	25–40	20–25	0–20
Internal friction angle (°)	35–45	30–35	20–30	15–20	0–15