Correct option is C
The Unconsolidated Undrained (UU) test is the most appropriate triaxial test to assess the immediate stability of an unloading problem, such as the excavation of a clay slope. This test is used to determine the shear strength of soil in scenarios where there is no time for drainage or consolidation, which matches the conditions during immediate unloading.
Detailed Explanation of Options:
1. CU Test (Consolidated Undrained Test):
Involves consolidation of the soil sample before shearing, but drainage is not allowed during shearing. This is not suitable for immediate stability problems.
2. Unconsolidated Drained Test:
Not a standard test; this option seems incorrect.
3. UU Test (Unconsolidated Undrained Test):
Suitable for rapid changes such as unloading in clay slopes.
No consolidation or drainage occurs during the test, mimicking real-world rapid unloading conditions.
4. CD Test (Consolidated Drained Test):
Allows for consolidation and full drainage, used for long-term stability analysis, not immediate stability.
