In soil mechanics, understanding the relationships between axial strain, pore water pressure, and volumetric strain under different conditions is essential for analyzing soil behavior in triaxial tests.
Matching Explanation:
- P. In a triaxial compression test, with increase of axial strain in loose sand under drained shear condition, the volumetric strain: When the sand is in a drained condition, the volumetric strain decreases because the sand particles rearrange without significant volume change due to drainage. Thus, P corresponds to (I) (decreases).
- Q. In a triaxial compression test, with increase of axial strain in loose sand under undrained shear condition, the excess pore water pressure: Under undrained conditions, when strain increases, the pore water pressure increases as there is no drainage. Thus, Q corresponds to (II) (increases).
- R. In a triaxial compression test, the pore pressure parameter “B” for a saturated soil: The parameter “B” remains constant for a saturated soil under undrained conditions. It is generally a function of the relative permeability and changes in pore pressure, but remains the same in this context. Thus, R corresponds to (V) (remains same).
- S. For shallow strip footing in pure saturated clay, Terzaghi’s bearing capacity factor (Nq) due to surcharge: The bearing capacity factor \( N_q \) for a surcharge in pure saturated clay is typically 1.0. This is an established value in Terzaghi’s bearing capacity theory for saturated soils. Thus, S corresponds to (V) (is always 1.0).
Conclusion:
Thus, the correct combination is option (A): (P)-(I), (Q)-(II), (R)-(V), (S)-(V).
