A direct shear test was conducted on dry sand with an area of the specimen 5 2 in. 3 2 in. The results were
|
Normal force (lb)
|
Shear force at failure (lb)
|
|
50
|
43.5
|
|
110
|
95.5
|
|
150
|
132.0
|
Graph the shear stress at failure against normal stress and determine the soil friction angle, f9.