Pop Quiz: Earthwork – Uncontained

Earthwork Quiz

1. What is the purpose of proof-rolling a soil subgrade?*

To increase the soil compaction.
To monitor for deflection.
To monitor for deformation.
To monitor for the presence of moisture.
All of these.
To monitor for deflection, deformation, and the presence of moisture.

2. When proof-rolling a soil subgrade, which of the following should be specified?*

The type of equipment to be used for the proof-rolling.
The maximum allowable deflection.
The required load on the subgrade.
The maximum dry density.
The optimum moisture.
The type of equipment to be used for the proof-rolling AND the maximum allowable deflection AND the required load on the subgrade.
The maximum dry density AND the optimum moisture.

3. Based on the picture of proof-rolling (above) with an unloaded three axle articulated truck, the exposed subgrade would be acceptable to build a load bearing structure on in its current condition?*

TRUE
FALSE

4. Refer to the image above. The results of proof-rolling this 2’ thick clay “bridging layer” placed over a failed proof-rolled subgrade indicate a subsurface stability problem likely still exists?*

TRUE
FALSE

5. Refer to the video above. The liquid and silt bubbling up in this video taken from exposed subgrade during excavation to base grades is an indicator of which of the following?*

Desiccation
Good Hydraulic Conductivity
Hydrostatic Uplift
The contractor hit an artesian well
None of these

6. When performing construction of compacted clay liners (CCL’s), compaction criteria often require “x” amount of passes to be made by the contractor and verified by CQA personnel. Which of the following is the best definition of ONE “pass”?*

Counting one contact of the compactor drum with a specific area of the CCL in the forward direction.
Counting one contact of the compactor drum with a specific area of the CCL in the reverse direction.
Counting one contact of the compactor drum with a specific area of the CCL in the both the forward direction AND one contact of the compactor drum with a specific area of the CCL in the reverse direction.
Any of the above, as specifically defined in the specifications and/or CQA Plan.
None of the above.

7. The drone photo above of compacted clay liner placement reveals a quality issue that needs to be addressed as soon as possible. Which one of the following is the issue shown in this photo?*