Unconfined Compression Test

Q. A clay soil specimen when tested in unconfined condition gave an unconfined compressive strength of $100kN/m^2$. A specimen of the same clay with the same initial condition is subjected to a $UU$ triaxial test under a cell pressure of $100kN/m^2$. Axial stress $($in $kN/m^2)$ at failure would be

1. $150$
2. $200$
3. $250$
4. $300$

Q. In an unconfined compression test on saturated clay, the undrained shear strength was found to be $6t/m^2$. If a sample of the same soil is tested in an undrained condition in a triaxial compression at a cell pressure of $20t/m^2$, then the major principal stress at failure will be:

1. $48t/m^2$
2. $32t/m^2$
3. $24t/m^2$
4. $12t/m^2$

Q. Unconfined compression test is most suitable for determining the
1. Sensitivity of clays
2. Settlement of embankments
3. 'Strength' of partially saturated clay sample
4. 'Strength' of fully saturated clay sample

1. $1,2,3$ and $4$
2. $2$ and $3$ only
3. $3$ and $4$ only
4. $1$ and $4$ only

Q. In a triaxial compression test, the major principal stress was $90kPa$ and the minor principal stress was $30kPa$, at failure. The pore pressure at failure was observed to be $10kPa$. The tangent of the angle of shearing resistance of the sandy soil that was tested was

1. $1/2$
2. $1/3$
3. $2/3$
4. $3/4$

Q. A cylindrical soil specimen of saturated clay, $3.50cm$ diameter and $8cm$ length, is tested in an unconfined compression testing machine. The specimen failed under a vertical load of $50kg$ together with an accompanying additional deformation of $8mm$. What is the unconfined compressive strength of this clay?

1. $4.67kg/c{m}^2$
2. $5.0kg/c{m}^2$
3. $5.5kg/c{m}^2$
4. $6.0kg/c{m}^2$

Q. Which one of the following conditions is valid in case of unconfined compression test in comparison to triaxial test?

1. Minor principal stress = 0
2. Minor principal stress = 0.5 x major principal stress
3. Minor principal stress = major principal stress
4. Major principal stress = 3 x minor principal stress

Q. When an unconfined compression test is conducted on a cylinder of soil, it fails under axial stress of $1.2kg/c{m}^2$. The failure plane makes an angle of ${50}^{\circ }$ with the horizontal. Determine the cohesion of the soil

1. 0.503

Q. In an unconfined compression test on stiff clay, if the failure plane made an angle of ${52}^o$ to the horizontal, what would be the angle of shearing resistance?

1. ${16}^o$
2. ${14}^o$
3. ${12}^o$
4. ${13}^o$

Q. Consider the following statements:
For pure clay, the shear strength parameters will be
1. Cohesion $c=O$ ; and angle of internal friction $\varphi$ will be maximum.
2. Cohesion c is maximum; and angle of internal friction $\varphi$ is also maximum.
3. Angle of internal friction $\varphi$ is zero, with some value of cohesion $c$.
Which of these statements is/are correct?

1. $1,2$ and $3$
2. $1$ only
3. $3$ only
4. $2$ only

Q. Consider the following statements:
1. Brittle behaviour of soils can be obtained when the soil is heavily over consolidated clay.
2. Remoulded cohesive clays show a tendency towards progressive failure.
3. Undisturbed sensitive clays show a tendency towards progressive failure.
Which of these statements are correct?

1. $1,2$ and $3$
2. $1$ and $3$ only
3. $1$ and $2$ only
4. $2$ and $3$ only

Q. An unconfined compression test yielded a strength of 0.1$N/m{m}^2$. If the failure plane is inclined at ${50}^{\circ }$ to the horizontal, what are the values of the shear strength parameters?

1. 0.042

Q. A shear test was conducted on a soil sample. At failure the ratio of $\frac{{\sigma }_1-{\sigma }_3}{2}to$$\frac{{\sigma }_1+\sigma 3}{2}$ is equal to unit. Which one of the following shear tests represents this condition?

1. Drained triaxial compression test
2. Undrained triaxial compression test
3. Undrained triaxial compression test
4. Unconfined compression test

Q. The unconfined compressive strength of a sample of clay is found to be $20kN/m^2$. The drained angle of internal friction of the soil is about ${27}^{\circ }$. The magnitude of pore water pressure at failure will be

1. Zero
2. 10 kPa
3. -10 kPa
4. -12 kPa