As per Rankine's theory of earth pressure, the inclination of failure planes is $$\left( {45 + {\phi \over 2}} \right)^\circ $$ with respect to the direction of the minor principal stress.

The above statement is correct for which one of the following options?

A square concrete pile of 10 m length is driven into a deep layer of uniform homogenous clay. Average unconfined compressive strength of the clay, determined through laboratory tests on undisturbed samples extracted from the clay layer, is 100 kPa. If the ultimate compressive load capacity of the driven pile is 632 kN, the required width of the pile is __________ mm. (in integer)

Bearing capacity factor N_c = 9; adhesion factor $$\alpha$$ = 0.7)

A raft foundation of 30 m $$\times$$ 25 m is proposed to be constructed at a depth of 8 m in a sand layer. A 25 m thick saturated clay layer exists 2 m below the base of the raft foundation. Below the clay layer, a dense sand layer exists at the site. A 25 mm thick undisturbed sample was collected from the mid-depth of the clay layer and tested in a laboratory oedometer under double drainage condition. It was found that the soil sample had undergone 50% consolidation settlement in 10 minutes. The time (in days) required for 25% consolidation settlement of the raft foundation will be ___________. (round off to the nearest integer)

A two-hour duration storm event with uniform excess rainfall of 3 cm occurred on a watershed. The ordinates of streamflow hydrograph resulting from this event are given in the table.

Considering a constant baseflow of 10 m³/s, the peak flow ordinate (in m³/s) of one-hour unit hydrograph for the watershed is ____________. (in integer)