1: Analysis of a simple slope using the Fellenius method of slices (10 marks)

Determine the factor of safety (FoS) of the trial slip surface of the slope using the Fellenius method of slices. Ignore the effect of water table.

The effective shear strength parameters are given as c’ = 10.49 (kN/m²) and φ’ = 26.4^◦ (degree). The dry unit weight of the soil (g) is 19.03 (kN/m³).

(Not to scale)

Note that b is the width of a slice. z is the height of a slice and h_w the height of water in a slice. Ignore the effect of h_w in this exercise.

Q2: Analysis of a simple slope using the computer program Slope/W (10 marks)

For the same problem in Q1, determine the critical factor of safety (FoS) using the computer program Slope/W.

https://www.geoslope.com/products/slope-w

(Note that the slope angle is approximately 28.18° and the slope height is 5.37 metre in Q1. One needs this information to create a graphical model in Slope/W.)

Q3: Comparison and discussion (10 marks)

(Hint: Discuss the assumptions involved in Q1 and Q2 and compare the result in Q2 with that in Q1. Draw a brief conclusion.)