Geomorphic Threshold and Landslide - Semi-quantitative Approaches for Landslide Assessment and Prediction - page 147

Shear Stress
Shear Strength ¼

W : cos h tan u
W

Safety Factor ¼ 1 ð 5 : 2 Þ

: sin h

tan u Co-ef cient of friction

u Angle of repose

W Weight of soil

ʸ Slope on scar face.

tan u

or ;

h

1 ð 5 : 3 Þ

tan

or ; tan u tan h ð 5 : 4 Þ

i.e. (Angle of repose/Angle of internal friction) (Slope on scar face).

In the present study the slope angle of Tindharia and Lower Paglajhora area is

≥

53 nite

slope stability model for cohesion less material and slope parallel seepage after
(Borga et al. 1998 ) also supports the Eq. ( 5.5 ).

° 20 ′ and 48 ° 20 ′ which always outweighs the angle of repose. The other inde

h
z ¼

P s
P w

tan h
tan

1 1 ð 5 : 5 Þ

u

H Thickness of total soil
Z Thickness of saturated soil
Ps Wet soil density
Pw Density of water
u

Angle of repose

ʸ Slope on scar face.

tan h
tan u

For maintaining the stability ' h ' is needed to be greater than ' z ' and 1

should be positive (Table 5.1 ).

tan h

So 1 ð 5 : 6 Þ

tan u

tan h

or ; 1 ð 5 : 7 Þ

tan u

or ; tan u tan h ð 5 : 8 Þ

or ; u h ð 5 : 9 Þ

(Angle of repose) ≥ (Slope on scar face)