Question

A 6 m deep slope is going to be excavated in a deep soil deposit. The geometry of the slope is shown in the following figure. Assume. The soil has the following properties:   

_yt = 19 kN/m³,              c_u = 20 kPa,           _u = 0^o   

R = 10 m,                      AB = 2 m         

Water table is well below the toe of the embankment. Note: only a is a variable input.

1. Find the net area and the centroid of this net area (sliding circle) for a given a.
2. Assume a slope batter angle of a ranging from 40^o to 60^o with an incremental step of 2.5^o. Accordingly, determine the factor of safety for this slope.
3. Plot the factor of safety against the slope batter angle.

6m Trial Circle for Slope Stability in Undrained Condition Centroid of the netarea AB 2m 18 16 14 12 10 Distance (m)

Answer 1

destor Ac'D far the Net rea ol pf ctor BCD 185 120°-C Bo-22 A 2m RE lom C 201cPa +and tana Cu FoS YHcasasina 19x6XcosKsina tama +00315 tana 6 cosa sina andtinL 15 auaolictr AC'D-aea lscuor &cD Arca 2. 360 130 16s 3600 4.8 m2 1 b Fos Tan

increaes Date Page No. angles 40 42545.044 S S0 52.5555.5 Gaa Fos .410.43 8.42 .O. 430.43 2.5 45 425 Plot fos vs Angle ler