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.

The effect of pressure on the electrical resistivity of water‐saturated crystalline rocks

Abstract: Electrical resistivity of eight igneous rocks and two crystalline limestones was measured at pressures to 10 kb. The rocks were saturated with tap water or salt solution, and the pore pressure was maintained near zero. The dependence of resistivity on temperature, porosity, and pore fluid salinity suggested that conduction was primarily electrolytic throughout the entire pressure range, even though the porosity of some rocks was less than 0.001. Resistivity increased with increasing pressure. The average increase over the 10-kb range amounted to a factor of 250. The changes of resistivity with pressure parallel changes of compressibility with pressure, being rapid over the first 2 kb and tapering off more gradually at higher pressures. The data suggest that the electrical conduction of these rocks consists of (1) conduction along cracks, below a few kilobars pressures, and (2) volume and surface conduction along a network of pores which persist throughout the entire pressure range. Surface conduction of the rocks saturated with tap water was 10 to 20 times greater than the volume conduction of the pores. The dependence of conductivity on porosity for all the samples saturated with saline solution followed the same empirical law that is observed for porous sedimentary rocks, σ(rock) = σ(solution) × η2.

Self-weight consolidation of soft soils: an experimental and theoretical study

Abstract: Soil is laid down by sedimentation through water, passing through the phases of a fluid supported suspension, through a loose structure to a soft soil, the stiffness of which then gradually increases under additional load. Consolidation is caused by the self-weight of the soil and, while the sediment is soft, is accompanied by large strains. To predict magnitudes and rates of movement, the physical processes must be understood and used as the basis of a theoretical model. This Paper describes laboratory experiments on the development and consolidation of a soft soil in settling columns, with measurement of density (using an accurate, non-destructive X-ray technique), total stress, pore pressure and settlement. The results are compared with an earlier theoretical model. Modifications made to the model in the light of observed experimental features allow it to be used to predict the laboratory consolidation. Le sol est depose par sedimentation a travers l'eau; il a d'abord la forme d'une suspension soutenue...

Acute Sensitivity of Landslide Rates to Initial Soil Porosity

Abstract: Some landslides move imperceptibly downslope, whereas others accelerate catastrophically. Experimental landslides triggered by rising pore water pressure moved at sharply contrasting rates due to small differences in initial porosity. Wet sandy soil with porosity of about 0.5 contracted during slope failure, partially liquefied, and accelerated within 1 second to speeds over 1 meter per second. The same soil with porosity of about 0.4 dilated during failure and slipped episodically at rates averaging 0.002 meter per second. Repeated slip episodes were induced by gradually rising pore water pressure and were arrested by pore dilation and attendant pore pressure decline.