Below you can see the graph of shear stress vs normal stress at failure for a clay sample.

Cohesion of clay is:

Select the incorrect statement considering the strength characteristics of loose sand and sand in a confined space

Consider this schematic diagram of a shear box during the direct shear test. We can calculate the shear stress during the test as:

Which of the following is not true considering loose sand?

A circular footing for an oil tank has a radius (a) of 4m.  The applied stress from the base of the footing to the ground surface (q) is 137 kPa. Determine the vertical stress increment, Δσ_z below the centre of the footing at 2 m below the foundation level.

As shown in the figure, the applied stress from the base of a lamp post (Q) is 22 kPa. Determine the vertical stress increment, Δσ_z at point A (r = 2m and z=2m) due to the point load of the lamp post.

State whether the following sentence is true or false.

Particle size distribution curve shows the relationship between the particle size and percentage passage of a soil sample.

As stated in the sieve analysis  lab video, what is the vibration frequency used in the mechanical shaker?

State whether the following sentence is true or false.

Pneumatic compaction and steel rod tamping is used to achieve the densest state to calculate the maximum dry density of sand.

After carefully rotating the measuring cylinder to obtain the minimum dry density, the surface of the sand sample becomes inclined. What is the value to be considered as the volume of the sand sample at this stage?