Assessment of Slope Instability and Risk Analysis of Road Cut Slopes in Lashotor Pass, Iran

Table 5

Adjustment factors 𝐹1, 𝐹2, 𝐹3, 𝐹4, and 𝐹5 and range of value in the SSR classification system (Taheri and Tani 2010) [6].

	Parameter		Range of values
𝐹1	Uniaxial compressive strength (MPa)		0–10	10–25	25–50	50–100	100–150	150–200
	Rating		0	7	18	28	37	43
𝐹2	Rock type		Group 1	Group 2	Group 3	Group 4	Group 5	Group 6
	Rating		0	4	9	17	20	25
𝐹3	Slope excavation method		Waste damp	Poor blasting	Normal blasting	Smooth blasting	Presplitting	Natural slope
	Rating		−11	−4	0	6	10	24
𝐹4	Groundwater	(Groundwater level from bottom of the slope/slope height) × 100	Dry	0–20%	20–40%	40–60%	60–80%	80–100%
	Rating		0	−1	−3	−6	−14	−18
𝐹5	Earthquake force	Horizontal acceleration	0	0.15 g	0.20 g	0.25 g	0.30 g	0.35 g
	Rating		0	−11	−15	−19	−22	−26