CCIL CCIL - Canadian Council of Independent Laboratories Soil Testing and Geotechnical Analysis Questions and Answers 1 — Questions and Answers
Question 1: According to ASTM D422, what is the standard sieve size used to separate coarse and fine fractions during a mechanical sieve analysis of soil?
- No. 4 (4.75 mm) (Correct answer)
- No. 10 (2.00 mm)
- No. 40 (0.425 mm)
- No. 200 (0.075 mm)
Correct answer: No. 4 (4.75 mm)
The No. 4 (4.75 mm) sieve is the standard dividing line between coarse and fine fractions in a mechanical sieve analysis per ASTM D422.
Question 2: Which ASTM standard governs the determination of the Liquid Limit of soils using the Casagrande device?
- ASTM D4318 (Correct answer)
- ASTM D1557
- ASTM D698
- ASTM D2487
Correct answer: ASTM D4318
ASTM D4318 covers the standard test methods for Liquid Limit, Plastic Limit, and Plasticity Index of soils.
Question 3: In the USCS soil classification system, what group symbol designates a well-graded gravel with little or no fines?
- GW (Correct answer)
- GP
- GM
- GC
Correct answer: GW
GW designates a well-graded gravel meeting specific Cu and Cc criteria with less than 5% passing the No. 200 sieve.
Question 4: What parameter is calculated as the ratio of the coefficient of uniformity (Cu) threshold check during USCS classification of gravels?
- Cu ≥ 4 and 1 ≤ Cc ≤ 3 (Correct answer)
- Cu ≥ 6 and 1 ≤ Cc ≤ 3
- Cu ≥ 4 and 1 ≤ Cc ≤ 2
- Cu ≥ 6 and 1 ≤ Cc ≤ 2
Correct answer: Cu ≥ 4 and 1 ≤ Cc ≤ 3
For GW classification, gravels must have Cu ≥ 4 and the coefficient of curvature Cc between 1 and 3.
Question 5: During a standard Proctor compaction test (ASTM D698), how many layers of soil are compacted into the mold?
- 3 layers (Correct answer)
- 5 layers
- 4 layers
- 2 layers
Correct answer: 3 layers
ASTM D698 specifies compacting soil in 3 equal layers using a 5.5 lb hammer dropped 12 inches, with 25 blows per layer.
Question 6: What does a Plasticity Index (PI) of zero indicate about a soil sample?
- The soil is non-plastic and has no range between liquid and plastic limits (Correct answer)
- The soil has equal liquid and plastic limits at high moisture
- The soil is highly expansive clay
- The soil cannot be classified by Atterberg limits
Correct answer: The soil is non-plastic and has no range between liquid and plastic limits
A PI of zero means the liquid limit equals the plastic limit, indicating the soil transitions directly from semi-solid to liquid with no plastic range.
CCIL CCIL - Canadian Council of Independent Laboratories Soil Testing and Geotechnical Analysis Questions and Answers 1
According to ASTM D422, what is the standard sieve size used to separate coarse and fine fractions during a mechanical sieve analysis of soil?