If β is the surcharge angle of a backfill with an angle of internal friction φ, the coefficient of active earth pressure given by Rankine's theory, is :

A structure is erected on an impervious clay whose thickness is 12 m. Drainage is possible both at upper and lower surfaces. Coefficient of consolidation is 0.015 cm^{2} per minute. For attaining 50% consolidation with a time factor 0.20, the number of days required

The intensity of active earth pressure at a depth of 10 metres in dry cohesionless sand with an angle of internal friction of 30° and with a weight of 1.8 t/m^{3}, is