Geotechnical Engineering Multiple Choice Questions on “Tri axial Compression Test”.
1. The Tri axial compression test was introduced by __________
a) A. casagrande and Karl Terzaghi
b) Mohr
c) None of the mentioned
d) All of the mentioned
Answer: a
Clarification: The tri axial compression test was first introduced in U.S.A by A. casagrande and Karl Terzaghi in 1936-37.
2. Which of the following strength test is commonly used in the laboratory?
a) Direct shear test
b) Confined compression test
c) Tri axial shear test
d) Unconfined shear test
Answer: c
Clarification: As a shear test can be performed under all three drainage condition, tri axial test is most commonly used in research laboratory.
3. Which of the following outlet is provided at the base of the tri axial test apparatus?
a) Cell fluid inlet
b) Pore water outlet
c) Drainage outlet
d) All of the mentioned
Answer: d
Clarification: Three outlet connections are generally provided through the base of the test apparatus: cell fluid test, pore water outlet from the bottom of the specimen and the drainage outlet from the bottom of the specimen.
4. Pore pressure developed in the tri axial test can be measured by ____________
a) Bishop’s apparatus
b) Pore pressure apparatus
c) Terzaghi’s apparatus
d) Mohr’s apparatus
Answer: a
Clarification: Pore pressure developed in the specimen during the test can be measured with the help of a separate pore pressure measuring equipment such as Bishop’s pore pressure apparatus developed by Bishop in 1950, 1961.
5. Bishop’s apparatus does not contain which one of the following equipment?
a) Porous disc
b) Top cap
c) Rollers
d) All of the mentioned
Answer: d
Clarification: Bishop’s apparatus mainly consists of the null indicator, the control cylinder, pressure gauge, mercury manometer and burette.
6. The vertical stress on the solid cylindrical test apparatus is applied by ____________
a) Major principal stress
b) Minor principal stress
c) Intermediate principal stress
d) All of the mentioned
Answer: a
Clarification: In tri axial test, the major principle stress σ1 is applied in the vertical direction, and the other two principal stresses σ and σ are applied in the horizontal direction by the fluid pressure round the specimen.
7. The deviator stress developed in the proving ring, through the applied pressure is equal to are____________
a) σ1 + σ3
b) σ1 – σ3
c) σ2 – σ3
d) σ2 + σ1
Answer: b
Clarification: The vertical stress applied by the loading frame, through the proving ring is equal to (σ1 – σ3); this stress difference is called the deviator stress.
8. When the sol is in the state of stress, it is said to be in _____________
a) Constant state
b) Plastic equilibrium
c) Stress conditioned state
d) Equilibrium condition
Answer: b
Clarification: When the soil is in the state of stress defined by the equation σ1’= σ3’tan2 α’ + 2c’ tan α’ as principal stress relationship, it is said to be in plastic equilibrium.
9. The deviator stress σd is given by __________
a) σd = σ1 + σ
b) σd = σ3 – σ1
c) σd=additional axial load/A2
d) σd = σ1 – σ3
Answer: c
Clarification: The deviator stress σd, is given as the ratio of additional axial load to the area A2 at failure or during at any stage of the test.
10. Which of the following is an advantage of using tri axial test?
a) Accurate result is not possible
b) The plane of shear failure is predetermined
c) Stress conditions are complex
d) Precise measurement
Answer: d
Clarification: In tri axial test, precise measurements of the pore pressure and volume change during the test are possible.