Triaxial testing capabilities: The standard triaxial apparatus can be configured to perform which of the following types of shear tests on soils?

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:

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