Pore Water Pressure (u) is primarily affected by which of the following?

Pore water pressure, denoted as ( u ), is influenced significantly by hydrostatic pressure, which is derived from the weight of the water column above the point of measurement within a saturated soil. This hydrostatic pressure is critical in determining how water behaves in the pores of the soil matrix, especially below the water table.

When considering the effects of hydrostatic pressure, it is clear that the pressure increases with depth in a fluid due to the weight of the water above. Therefore, at any point below the water table, the pore water pressure can be calculated based on the height of the water column above that point, multiplied by the specific weight of the water. The hydrostatic condition is key to evaluating the stability of soil structures, groundwater movement, and consolidation behavior.

Other factors, while they may influence aspects of soil behavior, do not primarily shape pore water pressure. The weight of the soil above does exert pressure but primarily influences total stress rather than pore water pressure specifically. The density of soil particles and the level of compaction affect soil's shear strength and consolidation characteristics but do not directly dictate the pore water pressure itself.

Hence, the most direct and relevant influence on pore water pressure at a point below the water table is the hydrostatic pressure