A saturated and undrained clayey slope is 10-m high and the slope

angle is 40 degrees. Subsurface investigation found that the subsoil is

homogeneous clay with undrained cohesion of 110 kN∕m² and satu-

rated unit weight of 19.5 kN∕m³. A stiff soil layer exists 5 meters below

the toe of the slope. A potential toe circle with the radius of 20 meters

passes the coordinate of (25 m, 10 m). The toe is at the origin (0, 0).

(1) Determine the factor of safety along the assumed slip circle using

the analytical mass method.

(2) Determine the minimum factor of safety of the slope using Taylor’s

chart.