Question

Q. 1.
State whether the followings are True or False?
(1) A porosity of 40% implies that 40% of the total volume consists of voids.
(2) The angle of internal friction can vary from 0 to 90˚ since it is an angle.
(3) Void ratio cannot be > 1.
(4) Clays can have both cohesion and angle of internal friction.
(5) The head loss between two points is the difference in water pressure head between the two points.
(6) In the triaxial test the horizontal plane is the major principal plane.
(7) Piping (failure due high exit hydraulic gradient downstream) starts upstream and then progress to downstream face of a concrete dam.
(8) It is safe to say that: in general natural soils in the field have larger permeability in the horizontal direction than the vertical direction.
(9) Consolidation is process of reducing voids by removing water and air if present.
(10) In seepage in two dimensional impervious boundaries are equipotential lines.
(11) Increasing the water pressure head at both upstream and downstream by 1 m will reduce piping.
(12) In seepage in two dimensional impervious boundaries are flow lines

Answer 1

1. The statement is true. This is because porosity is defined as the ratio of void volume with res[etct to the total soil volume mass. It is the application of this definition which is given here.

2. The statement is false. This is because the angle of internal friction with respect to the soil is one that ranges between 17 degrees and 32 degrees.

3..It is a true fact that the void ratio as mentioned in answer 1 can reach a maximum of 1.

4. The statement is true as internal friction is limited ranging between 2 and 3 degree whereas cohesion definitely exists.