Consider a slope given below with 10 slices, which has a circular failure surface. Each slice has 5 meters wide, and the weight of each slice was  estimated on the basis of average height and a unit weight of soil ? = 16 kN/m3. The shear strength of the soil is assumed to be ? = 20 kPa and ? = 20°. The pertinent data for these ten slices is given in the table below. a) Determine the factor of safety using Janbu’s simplified method by assuming the initial  ?? = ?. ?.    b) Discuss how the factor of safety (stability of the Slope) will change due to the rainfall. You start to consider what environmental conditions will change first.

An excavation is rapidly made on site as depicted in the Figure below. The soil wedge above the critical slip surface is divided into thirteen slices. Based on the ordinary method of slices, calculate the ratio (R/S) between the Resisting Force (R) and the Driving Force (S) for slice #3, shortly after the excavation is completed. (Acceptable tolerance = 4%). The geometry of slice #3 and the soil properties are provided in the tables below. The height of water at the middle of the slice is hw = 3.0 m. Note that the total weight of the slice is equal to the weight of the saturated soil below the water table plus the weight of the moist soil above the water table. Hint: the weight of slice #3 is 495 kN

For the trial slip circle shown in figure, calculate the factor of safety. [(Given: weight of the soil = 346 kN/m, unit weight of soil = 19 kN/m3, C = 20 kN/m2] %3D r=9 m 70° 5 m 7XXX

A vane shear test was conducted in a saturated soft clay,using a 100 mm 3 200 mm vane. When the vane was rotatedat the standard rate of 0.1°/s, the torque measured inthe torque meter increased to 60 N ? m, and with further rotationreduced to 35 N ? m. Determine the peak and residualundrained shear strengths of the clay.

2. Using 'Saw Tooth' model to (a) Display the shear behaviour of a dense soil, critical state and loose soil; (b) Explain, using the dense soil model, soil friction at constant volume and dilation and their relationship to peak friction angle.