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11
What is the function of a piezometer in site investigation?
Discuss
Answer & Solution
Answer: Option B
Solution:
A piezometer is used to measure the groundwater table or pore water pressure in soil or rock, which is critical for slope stability and foundation design.
12
Which type of boring method is suitable for soft cohesive soils?
Discuss
Answer & Solution
Answer: Option B
Solution:
Auger boring is economical and suitable for soft cohesive soils such as clays, allowing sample recovery without water circulation.
13
In SPT, how much is the hammer weight and drop height?
Discuss
Answer & Solution
Answer: Option B
Solution:
Standard SPT equipment uses a 63.5 kg hammer dropped from 76 cm height to drive the sampler, ensuring standardized results.
14
What does a low RQD (<25%) indicate?
Discuss
Answer & Solution
Answer: Option B
Solution:
Rock Quality Designation (RQD) less than 25% signifies poor quality, highly fractured rock, unsuitable for load-bearing without reinforcement.
15
Why is soil classification important in geotechnical exploration?
Discuss
Answer & Solution
Answer: Option C
Solution:
Soil classification enables engineers to predict behavior under load, drainage, and compaction, which is crucial for design and construction.
16
What is meant by the term "driller's log"?
Discuss
Answer & Solution
Answer: Option C
Solution:
A driller's log is a real-time record created by the driller to describe soil/rock type, depth, water inflow, and drilling resistance.
17
Which of the following is a non-destructive geophysical technique?
Discuss
Answer & Solution
Answer: Option C
Solution:
Electrical resistivity survey does not disturb the ground and is widely used to detect subsurface features like bedrock, water table, and voids.
18
What is a split spoon sampler used for?
Discuss
Answer & Solution
Answer: Option C
Solution:
Let's understand what a Split Spoon Sampler is and why it is used.

A split spoon sampler is a commonly used sampling device in geotechnical site investigations. It is primarily used during the Standard Penetration Test (SPT) to collect disturbed soil samples from a borehole while also helping determine the soil's strength and density.

The sampler is a hollow steel tube that is driven into the soil using repeated hammer blows. During this process, the soil inside the sampler gets compressed and its natural structure is disturbed. As a result, the collected sample is classified as a disturbed soil sample rather than an undisturbed one.

Option A: Sampling rock cores

This is incorrect. Rock cores are obtained using core barrels with diamond or carbide drill bits, not a split spoon sampler.

Option B: Sampling water

This is incorrect. Water samples are collected using specialized groundwater sampling equipment or pumps.

Option C: Collecting disturbed soil samples

This is correct. Since the split spoon sampler is driven into the ground by hammer blows, it collects disturbed soil samples. These samples are suitable for soil identification and classification but not for determining the soil's undisturbed engineering properties.

Option D: Collecting undisturbed soil samples during SPT

This is incorrect. The driving action of the Standard Penetration Test (SPT) disturbs the soil. Undisturbed samples are collected using devices such as the Shelby tube sampler or a piston sampler.

Therefore, the correct answer is Option C: Collecting disturbed soil samples.

Exam Tip: Remember the simple rule: Split Spoon Sampler → SPT → Disturbed Sample, whereas Shelby Tube Sampler → Undisturbed Sample.
19
What does a permeability test help determine in foundation design?
Discuss
Answer & Solution
Answer: Option C
Solution:
Permeability influences drainage, pore pressure, and seepage, which are critical for foundation, earth dams, and slope stability.
20
What is the purpose of core recovery in rock drilling?
Discuss
Answer & Solution
Answer: Option C
Solution:
Core recovery provides direct visual and physical evidence of rock condition, structure, and quality, vital for design and stability assessment.