When the well is sunk deeper, the skin friction is decreased by which of the following method?

A disadvantage in using circular shape of well foundation is _______

The cutting edge should be provided with an angle of ______

In order to assist sinking of well ______ method is used in pneumatic caissons.

Coefficient of horizontal soil reaction m, depends on _____

Which of the following caissons, permits excavation in dry?

The allowable pressure that is allowed inside the working chamber of pneumatic caissons is ___

Disadvantage of using pneumatic caissons are ____