Consider the following objectives related to the sub-surface investigation: 1.To establish the geological profile. 2.To establish Hydrogeological conditions. 3.To monitor future changes in ground conditions through instrumentation. Which of the above objectives are correct?
- A1 and 2 only
- B2 and 3 only
- C1 and 3 only
- D1, 2 and 3Correct
Solution
Concept
Sub-surface investigation finds the ground profile and groundwater conditions, and can also set up instruments to monitor future changes.
Step-by-step solution
1. Statement 1: finding the geological profile (layers and their depth) is a basic objective. Correct. 2. Statement 2: finding groundwater and hydrogeological conditions is an objective. Correct. 3. Statement 3: installing instruments (piezometers, inclinometers) to monitor future changes is also an objective. Correct. 4. All three are correct, so the answer is D.
Explanation
Sub-surface investigation gives the soil and rock layers and the groundwater conditions. It is also used to install instruments that watch the ground over time. So all three objectives are correct.
Why the other options are wrong
A, B and C each leave out one correct objective.
Shortcut
Profile + water + monitoring = all are objectives of site investigation.
Common mistake
Leaving out 3 by thinking that monitoring is not part of investigation.
Correct answer: D) 1, 2 and 3