Triaxial testing capabilities: The standard triaxial apparatus can be configured to perform which of the following types of shear tests on soils?
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AUnconsolidated–undrained (UU) test
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BConsolidated–undrained (CU) test
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CDrained (CD) test
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DAll the above tests
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ENone of these
Answer
Correct Answer: All the above tests
Explanation
Introduction / Context:Triaxial testing is the workhorse of laboratory shear strength measurement in soil mechanics. By controlling drainage and consolidation, it produces parameters for short-term undrained and long-term drained conditions, and intermediate behaviors with pore pressure measurement (CU).
Given Data / Assumptions:
- Standard triaxial cell with confining pressure control.
- Drainage valves and back-pressure saturation available.
- Accurate measurement devices for load, deformation, and pore pressure (as applicable).
Concept / Approach:
The triaxial apparatus can run: UU (no consolidation, no drainage), CU (consolidation allowed, no drainage during shear, pore pressure measured), and CD (consolidation allowed, full drainage during shear). Thus the apparatus supports all three classic test types.
Step-by-Step Solution:
Match test goals to drainage/consolidation settings.UU → quick undrained; CU → staged with pore pressures; CD → slow drained.Conclusion: all listed tests are feasible with the triaxial apparatus.Verification / Alternative check:
Laboratory standards and textbooks detail procedures for UU, CU, and CD in triaxial devices.
Why Other Options Are Wrong:
Each single-option choice omits valid capabilities; “None” is incorrect.
Common Pitfalls:
Confusing CU with CD; neglecting rate control for CD to ensure drained conditions.
Final Answer:
All the above tests