Pore water pressure

About: Pore water pressure is a research topic. Over the lifetime, 11455 publications have been published within this topic receiving 247670 citations. The topic is also known as: pwp.

In situ study of the physical mechanisms controlling induced seismicity at Monticello Reservoir, South Carolina

Abstract: In two ∼1.1-km-deep wells, the magnitudes of the principal in situ stresses, pore pressure, permeability, and the distribution of faults, fractures, and joints were measured directly in the hypocentral zones of earthquakes induced by impoundment of Monticello Reservoir, South Carolina. Analysis of these data suggests that the earthquakes were caused by an increase in subsurface pore pressure sufficiently large to trigger reverse-type fault motion on preexisting fault planes in a zone of relatively large shear stresses near the surface. The measurements indicated (1) near-critical stress differences for reverse-type fault motion at depths less than 200–300 m, (2) possibly increased pore pressure at depth relative to preimpoundment conditions, (3) the existence of fault planes in situ with orientations similar to those determined from composite focal plane mechanisms, and (4) in situ hydraulic diffusivities that agree well with the size of the seismically active area and time over which fluid flow would be expected to migrate into the zone of seismicity. Our physical model of the seismicity suggests that infrequent future earthquakes will occur at Monticello Reservoir as a result of eventual pore fluid diffusion into isolated zones of low permeability. Future seismic activity at Monticello Reservoir is expected to be limited in magnitude by the small dimensions of the seismogenic zones.

The equivalent pore pressure and the swelling and shrinkage of cement-based materials

Abstract: We revisit the approach to the drying shrinkage of cement-based materials using Poromechanics of unsaturated materials. It is in particular shown that the equivalent pore pressure concept, by opposition to the averaged pore pressure, can account for the surface energy effect upon the drying shrinkage. Experimental evidence shows that the influence of the latter reveals to be essential for intermediary values of the relative humidity since the contribution of the interfacial energy significantly increases as the relative humidity is reduced.

Finite element analysis of coupled heat and moisture transfer in concrete subjected to fire

Abstract: A system of coupled transient differential equations governing heat, mass transfer, and pore pressure built up in porous media (concrete), subjected to intensive heating, is derived. Water vapor and liquid water are considered separately in the mass transfer formulation. The primary unknowns are temperature, water vapor content, and pore pressure of the gaseous mixture. A finite element formulation and corresponding flowchart of computations of all required data are presented. The numerical example solved represents a cross section of a concrete column exposed to fire. The domain and time distributions of temperature, pore pressure, water vapor, and liquid water content are presented. Computed pore pressure is higher than those usually reported by other analytical studies. The influence of some initial parameters (permeability, initial water content, and porosity) on maximum pore pressure is investigated.