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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.


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Journal ArticleDOI
TL;DR: The results indicate that physical and chemical processes within the pile are strongly coupled and cannot be considered separately when oxidation rates are high and influence gas transport as a result of heat generation.

151 citations

Journal ArticleDOI
TL;DR: In this article, a combination of field and laboratory tests was carried out recently to investigate the triggering effect of rainfall on shallow slips in alpine moraine slopes, with particle sizes varying from silts to boulders.
Abstract: In comparison with saturated conditions, negative pore water pressures arising from partial saturation increase the available shear strength on a potential slip surface. This additional contribution is lost progressively during infiltration of rainfall, leading to instabilities, sometimes before full saturation is reached. In such cases, reliable prediction of the safety factor may be achieved, by taking the suction history of the soil into account. A combination of field and laboratory tests was carried out recently to investigate the triggering effect of rainfall on shallow slips in alpine moraine slopes. The problem is complicated by the strong heterogeneity of these soils, with particle sizes varying from silts to boulders. The data highlight the influence of suction on the peak shear strength, and allow for the calibration of simple models, which take into account the dependence of shear strength on the saturation degree. An infinite slope stability analysis is performed. The results are compared wit...

150 citations

Journal ArticleDOI
TL;DR: Time-domain reflectometry (TDR) has been used for in situ, non-destructive measurement of water, ionic solutes and air within the soil profile as discussed by the authors.
Abstract: Soil water exerts a strong influence on the transfer and storage of solutes, heat, air, and even water itself, within the soil profile. Soil water also dominates the mass and energy balance of the soil–atmosphere interface. Over the last decade or so, the development and continuing refinement of the time-domain reflectometry (TDR) technique for in situ, nondestructive measurement of water, ionic solutes and air has revolutionized the study and management of the transfer and storage of mass and energy within the soil profile. TDR-measured water content has been applied successfully to water balance studies ranging from the km scales of small watersheds to the mm scale of the root–soil interface. TDR-measured ionic solute status, which applies to the same sample volume as the water content measurement, has been used successfully on soil column, field plot and whole field scales for in situ determination of solute transport parameters, such as pore water velocity and dispersivity. TDR-measurement of air-filled porosity in space and time has given new insights into the mechanisms controlling aeration and gaseous exchange in the crop root zone. The combined water content – solute mass measurement capability of TDR has made this technique a very powerful tool for characterizing solute leaching characteristics, as well as for evaluating solute transport theories and solute transport models. The portability of TDR instrumentation coupled with the simplicity and flexibility of TDR soil probes has allowed the separation of water and solute content measurement error from soil variability, resulting in the capability for determining the mechanisms behind the spatial and temporal variability in field-based soil water content distributions and solute leaching patterns. The usefulness and power of the TDR technique for characterizing mass and energy in soil is increasing rapidly through continuing improvements in operating range, probe design, multiplexing and automated data collection.

150 citations

Journal ArticleDOI
TL;DR: In this paper, the authors introduce a dynamic capacity model to describe a critical reservoir pore pressure value that corresponds to either the sealing capacity of the fault against which the sand abuts or the pressure required to hydraulically fracture the overlying shale or fault.
Abstract: Hydrocarbon phase pressures at the peak of two severely overpressured reservoirs in the South Eugene Island 330 field, Gulf of Mexico, converge on the minimum principal stress of the top seal. We interpret that the system is dynamically constrained by the stress field present through either fault slip or hydraulic fracturing. In two fault blocks of a shallower, moderately overpressured reservoir sand, hydrocarbon phase pressures are within a range of critical pore pressure values for slip to occur on the bounding growth faults. We interpret that pore pressures in this system are also dynamically controlled. We introduce a dynamic capacity model to describe a critical reservoir pore pressure value that corresponds to either the sealing capacity of the fault against which the sand abuts or the pressure required to hydraulically fracture the overlying shale or fault. This critical pore pressure is a function of the state of stress in the overlying shale and the pore pressure in the sand. We require that the reservoir pore pressure at the top of the structure be greater than in the overlying shale. The four remaining reservoirs studied in the field exhibit reservoir pressures well below critical values for dynamic failure and are, therefore, considered static. All reservoirs that are dynamically constrained are characterized by short oil columns, whereas the reservoirs having static conditions have very long gas and oil columns.

150 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of pore pressure on velocities in the upper basaltic regions of the oceanic crust was investigated and it was concluded that pore pressures may be at least in part responsible for the low upper crustal velocity and contribute significantly to lateral variability.
Abstract: Summary Marine refraction studies during the past decade have found considerable lateral variability in the seismic properties of the upper basaltic regions of the oceanic crust. In many localities, compressional and shear-wave velocities are quite low at the top of the basalt section and velocities increase rapidly with depth. It is concluded that pore pressure may be at least in part responsible for the low upper crustal velocities and contribute significantly to the lateral variability. This is supported by compressional and shear-wave velocity measurements as functions of confining pressure and pore pressure for basalt from the Juan de Fuca ridge and dolerite from the Samail ophiolite, Oman. Within the oceanic crust, regions of overpressure and underpressure will possess anomalous velocities, the magnitude of which will depend upon the porosity and the deviation of the pore pressure from hydrostatic. The influence of pore pressure on velocities is expected to diminish with depth and is unlikely to be significant at lower crustal depths where porosity is extremely low. Of significance, Poisson's ratio is shown to be dependent on pore pressure as well as confining pressure. At constant confining pressure, Poisson's ratio increases with increasing pore pressure. Thus, overpressured regions within the upper oceanic crust are likely to have relatively high Poisson's ratios as well as low compressional- and shear-wave velocities.

150 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023552
2022995
2021572
2020564
2019566
2018566