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Showing papers on "Pore water pressure published in 1976"


01 Jan 1976
TL;DR: In this paper, the authors developed an understanding of the factors determining and controlling the engineering properties of soil, the factors controlling their magnitude, and the influences of environment and time, and developed a two-part book which contains the following chapters: Part 1 - the nature of soils; bonding, crystal structure and surface characteristics; soil mineralogy; soil formation and soil deposits; determination of soil composition; soil water; clay-water-electrolyte system; soil fabric and its measurement; Part 2 - soil behavior; soil composition and engineering properties; effective, intergranular
Abstract: The book is intended to develop an understanding of the factors determining and controlling the engineering properties of soil, the factors controlling their magnitude, and the influences of environment and time. The two-part book contains the following chapters: Part 1 - the nature of soils; bonding, crystal structure and surface characteristics; soil mineralogy; soil formation and soil deposits; determination of soil composition; soil water; clay-water-electrolyte system; soil fabric and its measurement; Part 2 - soil behavior; soil composition and engineering properties; effective, intergranular and total stress; soil structure and its stability; fabric, structure and property relationships, volume change behavior; strength and deformation behavior; and, conduction phenomena. /TRRL/

3,283 citations


Journal ArticleDOI
TL;DR: A sampler for defining compositional changes over distances on the order of 1 cm in aqueous systems operates by equilibration of water contained by a dialysis membrane with the surrounding water.
Abstract: A sampler for defining compositional changes over distances on the order of 1 cm in aqueous systems operates by equilibration of water contained by a dialysis membrane with the surrounding water. Depth profiles of methane and phosphate in Hudson Estuary sediments are presented as examples.

728 citations


Journal ArticleDOI
26 Mar 1976-Science
TL;DR: An experiment in an oil field at Rangely, Colorado, has demonstrated the feasibility of earthquake control and confirmed the predicted effect of fluid pressure on earthquake activity and indicated that earthquakes can be controlled wherever the authors can control the fluid pressure in a fault zone.
Abstract: An experiment in an oil field at Rangely, Colorado, has demonstrated the feasibility of earthquake control. Variations in seismicity were produced by controlled variations in the fluid pressure in a seismically active zone. Precise earthquake locations revealed that the earthquakes clustered about a fault trending through a zone of high pore pressure produced by secondary recovery operations. Laboratory measurements of the frictional properties of the reservoir rocks and an in situ stress measurement made near the earthquake zone were used to predict the fluid pressure required to trigger earthquakes on preexisting fractures. Fluid pressure was controlled by alternately injecting and recovering water from wells that penetrated the seismic zone. Fluid pressure was monitored in observation wells, and a computer model of the reservoir was used to infer the fluid pressure distributions in the vicinity of the injection wells. The results of this experiment confirm the predicted effect of fluid pressure on earthquake activity and indicate that earthquakes can be controlled wherever we can control the fluid pressure in a fault zone.

626 citations


Journal ArticleDOI
TL;DR: In this paper, the pore water velocity was estimated by measuring the solute displacement within each subplot and the entire field and was found to be logarithmically normally distributed and in agreement with volumetric measures of water infiltration rates.
Abstract: Solute distributions within a soil profile during the leaching of water-soluble salts applied to the soil surface were measured at six depths to 182.4 cm within 20 subplots of a 150-ha field. Estimates of the pore water velocity based upon measures of solute displacement within each subplot and the entire field were found to be logarithmically normally distributed and in agreement with volumetric measures of water infiltration rates. Such agreement was only possible because it was recognized that the observed values were not normally distributed, and their mean values were calculated accordingly. The number of observations required to yield an estimate of the mean pore water velocity within a prescribed accuracy is shown to depend upon the nature and extent of the spatial variability of the field soil. For the field examined, 100 observations would allow the mean pore water velocity to be estimated within ±50% of its true value. The functional relation between field-measured values of the apparent diffusion coefficient, also found to be logarithmically normally distributed, and pore water velocity is examined and interpreted in terms of solute distributions likely to be measured at specific sampling sites.

444 citations


Journal ArticleDOI
TL;DR: In this article, an analytical procedure is presented for evaluating the general characteristics of pore-water pressure buildup and subsequent dissipation in sand deposits both during and following a period of earthquake shaking.
Abstract: An analytical procedure is presented for evaluating the general characteristics of pore-water pressure buildup and subsequent dissipation in sand deposits both during and following a period of earthquake shaking. It is shown that in layers of fine sand, excess hydrostatic pressures may persist for an hour or more after an earthquake. However evidence of subsurface liquefaction may not appear at the ground surface until several minutes after the shaking has stopped and the critical condition at the ground surface may not develop until 10 min-30 min after the earthquake. However, for coarse sands and gravels with an impedance of drainage due to the presence of sand seams or layers, pore pressures generated by earthquake shaking may dissipate so rapidly that no detrimental build-up of pore pressure or a condition approaching liquefaction can develop. Improving the drainage capability of a sand deposit may thus provide an effective means of stabilizing a potentially unstable deposit. Analyses of the type described also provide the means for assessing whether subsurface liquefaction will have any serious effects on structures supported near the ground surface.

217 citations


Journal ArticleDOI
TL;DR: In this article, an experimental assembly was developed to conduct concurrent measurements of compressional and shear wave velocities in rocks at high temperatures and confining pressures and with independent control of the pore pressure.
Abstract: A description is presented of an experimental assembly which has been developed to conduct concurrent measurements of compressional and shear wave velocities in rocks at high temperatures and confining pressures and with independent control of the pore pressure. The apparatus was used in studies of the joint effects of temperature, external confining pressure, and internal pore water on sonic velocities in Westerly granite. It was found that at a given temperature, confining pressure has a larger accelerating effect on compressional waves in dry rock, whereas at a given confining pressure, temperature has a larger retarding effect on shear waves.

92 citations




Journal Article
TL;DR: In this article, comments are made regarding the influence of the pore fluid composition on soil structure, the dispersion-cohesion boundary and the Pinhole Test, and determinations of the critical shear stress of core samples.
Abstract: Comments are made regarding the influence of the pore fluid composition on soil structure, the dispersion-cohesion boundary and the Pinhole Test, and determinations of the critical shear stress of core samples. It is noted that different clay minerals have different boundary curves, which is presumably a factor in the width of the "Dispersive or Nondispersive" band. The uncertainity inherent in the Pinhole Test is also a factor which contributes to the band of uncertainity. This test is an empirical test based on subjective evaluation of the occurrence of dispersion, and its use to evaluate the critical shear stress on soil is inaccurate. The rotating cylinder test, using loss of weight as a measure of erosion, provides accurate determinations of the critical shear stress of core samples or remolded samples of cohesive soils, so long as vertical variations in soil properties are not significant over the length of the sample.

83 citations


Journal ArticleDOI
TL;DR: In this paper, the pore waters of Hole 149 (DSDP) exhibit a strong depletion in Mg and a corresponding enrichment in Ca, while the alkalinity remains relatively constant.

78 citations


Journal ArticleDOI
TL;DR: A modified version of the pistonless sediment squeezer developed by Reeburgh (1967) was designed to be used on the unconsolidated, fine-grained sediments of the Great Lakes.
Abstract: A simple, small-volume, low pressure, diaphragm-type sediment squeezer made from inexpensive standard nylon stock material, suitable for trace metal studies, features a removable sediment cassette with prefilter which greatly facilitates loading and cleaning. Pore water is recovered rapidly through a large active area membrane filter without clogging, impermeable cake formation, or gas breakthrough. A minimal pore water dead volume significantly reduces flushing losses and facilitates online electrode measurements. The squeezer is designed to accept small quantities of unconsolidated sediment (20-100 ml) from refrigerated cores sectioned in a nitrogen-filled glove box. Here we describe a modified version of the pistonless sediment squeezer developed by Reeburgh (1967)) designed to be used on the unconsolidated, fine-grained sediments of the Great Lakes. Several systems for the acquisition of sediment pore water described recently rep1 Contribution 201 from the Great Lakes Research Division, University of Michigan. resent tangible improvements over earlier models (Siever 1962; Presley et al. 1967; Reeburgh 1967). However, none is entirely suited to our work with anoxic sediment cores from the Great Lakes. The hydraulic, piston squeezer of Kalil and Goldhaber ( 1973) is designed for use with consolidated sediments which are sectioned by cutting through the core liner. We often obtain fluid material not amenable to this type of treatment. The in situ interstitial water sampler of Barnes ( 1973) is designed primarily for the study of dissolved gases in deep-sea sediments. It is not appropriate for trace metal analysis and cannot provide the required vertical resolution near the sediment-water interface. The large-volume squeezer described by Sasseville et al. (1974) is unsuitable for several reasons. In the operation of their system the sediments are exposed to air during transfer from corer to squeezer. The sensitivity of concentrations of dissolved phosphate (Bray et al. 1973; Weiler 1973) and iron (Troop

Journal ArticleDOI
TL;DR: In this article, an in situ sampler for pore waters of marine sediments is described, where filtered pore water from six depths in the upper 2 m of sediment and bottom water are collected and stored in capillary tubing, thereby preserving sampling sequence.

Book ChapterDOI
Robert A. Berner1
01 Jan 1976
TL;DR: In this paper, the processes of organic matter decomposition, dissolution and precipitation of minerals, rapid (equilibrium) adsorption and ion exchange, ionic diffusion, bioturbation, flow of water due to compaction, and "flow" of water plus enclosing solids away from the sediment-water interface due to depositional burial.
Abstract: The nonequilibrium assemblage of minerals, organic matter, and sea water deposited to gether in marine sediments brings about chemical reactions which appreciably change the composition of near-surface interstitial waters from the typical sea water values present at the time of deposition. Many of the most important reactions are the result of the microbiological decomposition of organic matter. Large changes in the concentrations of dissolved O2, NO 3 - , SO 4 2- , HCO 3 - , Ca2+, NH 4 + , CO2, CH4, H2S, Fe2+, Mn2+, and orthophosphate have been shown by previous studies to result directly or indirectly from microbiological activity. The rate at which sedimentary chemical reactions occur is not well known but can be determined, in principle, by laboratory studies combined with kinetic modeling of concentration-depth data. Mathematical models are presented here which express in outline form the processes of organic matter decomposition, dissolution and precipitation of minerals, rapid (equilibrium) adsorption and ion exchange, ionic diffusion, bioturbation, flow of water due to compaction, and “flow” of water plus enclosing solids away from the sediment-water interface due to depositional burial. Many of these processes are complex and are treated in the literature in an incorrect or oversimplified manner. Because of gradients in chemical composition, fluxes of dissolved constituents between sediment pore waters and overlying bottom waters must occur. Calculations of fluxes are fraught with difficulties and are often incorrect due to: incorrect formulation and estimation of gradients and of dif fusion coefficients; lack of an evaluation of the role of turbulent mixing at the sediment- water interface due to waves, currents, and bioturbation; lack of correction for depositional burial of pore waters; and lack of consideration of diffusion within the viscous-conductive sublayer of the bottom water.

Journal ArticleDOI
TL;DR: Pore-water pressure response in saturated intact specimens of Berea sandstone, Salem limestone, Vermont marble and Barre granite to undrained increase in all-round stress, was measured in a special...
Abstract: Pore-water pressure response in saturated intact specimens of Berea sandstone, Salem limestone, Vermont marble and Barre granite to undrained increase in all-round stress, was measured in a special...

Journal ArticleDOI
TL;DR: In this article, a microgranodiorite under undrained conditions at a pressure of 0.448 GPa and temperatures up to 720 °C was used for deformation experiments.
Abstract: Deformation experiments have been carried out on a microgranodiorite under undrained conditions at a pressure of 0.448 GPa and temperatures up to 720 °C. The granodiorite contained a small amount of chlorite and amphibole minerals which decomposed at elevated temperatures, giving rise to a pore pressure. Evidence about the decomposition reaction was obtained from differential thermal analysis and optical microscopy. In some experiments small amounts of free water were enclosed with the sealed rock sample. The strength (at fracture or 2 per cent strain) fell to very low values (∼0.02 GPa) at ∼700 °C, and at temperatures of 670 °C and above there was evidence of partial melting which led to ductile behaviour. At somewhat lower temperatures the rock was relatively weak but brittle.

Journal ArticleDOI
TL;DR: In this article, experiments have been carried out at atmospheric temperature and confining pressures up to 5 kb in which rocks, of different porosities, and fitted with flexible jackets, have been deformed up to 6 per cent axially while containing pore water under undrained conditions.
Abstract: Summary Experiments have been carried out at atmospheric temperature and confining pressures up to 5 kb in which rocks, of different porosities, and fitted with flexible jackets, have been deformed up to 6 per cent axially while containing pore water under undrained conditions. Application of a confining pressure and axial compressive stress creates a pore pressure, which weakens and embrittles the rocks under these conditions. The initial pore pressure may take any value up to that of the confining pressure, depending on the amount of water available inside the jacket and sample. Dilatancy produced by crack propagation during shear deformation resulted in dilatancy hardening which prevented or delayed mechanical instability (as manifested by stress drops). The greatest amount of dilatancy occurred during the fracturing process, but dilatancy decreased as the effective confining pressure increased. Only a small amount of dilatancy occurred during subsequent movement on faults, and the diIatancy tended to reach a stable value at deformations of ∼5 per cent (∼1.5 mm of movement on a major fault surface). There is evidence of small quasicyclic variations of dilatancy at greater deformations, which produce small stress drops of ∼50 b. The implications for crustal faulting and earthquake premonitory effects are discussed.

Journal ArticleDOI
TL;DR: In this article, an ASET of equations was developed for predicting particle-size distribution of eroded soil, based on soil surface area and texture and con-sidering organic matter enrichment and the tendency of a soil to rill.
Abstract: ASET of equations was developed for predicting particle-size distribution of eroded soil, based on soil surface area and texture and con-sidering organic matter enrichment and the tendency of a soil to rill. Three parameters—particle-size distribution of the matrix soil, organic matter, and water content at -15 bars pore pressure gave a good estimate of the expected particle-size distribution.

01 Jan 1976
TL;DR: A telemetering differential piezometer was designed and constructed at the Norwegian Geotechnical Institute to measure a minimum differential pressure (pore-pressure referenced to hydrostatic pressure) of 34 kPa and a maximum pressure of 294kPa in water depths of up to 500 m as mentioned in this paper.
Abstract: A telemetering differential piezometer was designed and constructed at the Norwegian Geotechnical Institute to measure a minimum differential pressure (pore-pressure referenced to hydrostatic pressure) of 34 kPa and a maximum pressure of 294kPa in water depths of up to 500 m. An emplacement system was built at the University of Illinois. One successful in situ test in the Wilkinson Basin, in a water depth of 274 m, yielded a maximum excess pore-pressure of 59 kPa after the probe was driven about 3-2 m into the silty-clay bottom. An excess pore-pressure of 9-8 kPa was measured 5-10 h after emplacement of the probe. Implications of excess pore-pressures cyclically generated by storm and internal wave loading of sea-floor soils is discussed. It is concluded that a better understanding of submarine slope stability through the use of the effective stress principle should now be possible by measuring pore-pressure in situ.

Journal ArticleDOI
TL;DR: In this paper, the axial deformations, pore pressure, and both axial and radial stresses were measured directly, thereby providing a continuous record of the stress and strain history of each sample.
Abstract: Two clay slurries with different controlled chemistries (flocculated and dispersed) were consolidated in large-diameter rigid cylindrical slurry consolidometers. During two cycles of consolidation and rebound, the axial deformations, pore pressure, and both axial and radial stresses were measured directly, thereby providing a continuous record of the stress and strain history of each sample. The coefficient of lateral earth pressure at-rest, K\do, was found to remain essentially constant during the loading phase of a loading-unloading cycle, but its value increased gradually during unloading until it exceeded unity when the overconsolidation ratio was about 2. Several indirect approaches were used to compute K\do from shear strength parameters determined from triaxial compression tests on specimens trimmed from block samples of the same two clays for which direct measurements were obtained, and the results were found to be in good agreement. Within the scope of the test data, neither pore fluid chemistry nor the associated clay fabric exerted much influence of the measured (during loading) values of K\do, which were in the range of 0.70 ±\N0.05.

Journal ArticleDOI
TL;DR: Following the McCormick County, South Carolina, local magnitude 43 earthquake on August 2, 1974, continuous seismic activity has been observed in the area The epicenters are located within 3 km from the Clark Hill reservoir.

Journal ArticleDOI
TL;DR: In this article, the authors describe the instrumentation, initial results, and progress of an experiment designed to measure and monitor submarine sediment pore water and hydrostatic pressures in a selected area of the Mississippi Delta.
Abstract: This report describes the instrumentation, initial results, and progress of an experiment designed to measure and monitor submarine sediment pore water and hydrostatic pressures in a selected area of the Mississippi Delta. The experiment also is intended to monitor significant pressure perturbations during active storm periods. Initial analysis of the data revealed excess pore water pressures in the silty clay sediment at selected depths below the mudline. Continuous monitoring of the pore water and hydrostatic pressures was expected to reveal important information regarding sediment pore water pressure variations as a function of the geological processes active in the Mississippi Delta.

Journal ArticleDOI
TL;DR: The use of two-dimensional fourier transforms of reservoir topography allows substantial increases in the speed of computation of loading effects on layered elastic models of the earth and on porous fluid-filled models as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, a dilatancy effect was introduced that is based upon Rowe's stress-dilatancy relation and the assumption of a linear relationship between the principal stress ratio and the major principal strain.
Abstract: Pore pressures near a moving boundary of a saturated soil mass are calculated and compared with tests. For a more realistic approximation of the stress-strain behavior of soil, a dilatancy effect has been introduced that is based upon Rowe’s stress-dilatancy relation and the assumption of a linear relationship between the principal stress ratio and the major principal strain. The field equations for the problem have been transformed to account for the traveling boundary. A psuedo three-dimensional consolidation theory is used to describe the fluid-soil skeleton interaction. The results of the computations were compared with pore-pressure measurements and showed reasonable agreement if dilatancy was taken into account.


Journal ArticleDOI
01 Jan 1976
TL;DR: In this paper, a differential piezometer probe was successfully implanted in the soft seafloor sediments of Block 28, South Pass, Mississippi Delta, and an ambient excess pore pressure of approximately 32 kPa remained after dissipation of that developed during probe installation.
Abstract: In September 1975, a differential piezometer probe was successfully implanted in the soft seafloor sediments of Block 28, South Pass, Mississippi Delta. The probe sensor is located approximately 6.4 m below the mudline in a water depth of 19 m, and has essentially continuously monitored excess pore pressure (the difference between sediment pore pressure and hydrostatic pressure at that depth) since installation. Excess pore pressure will be monitored until March 1976, when the probe will be recovered. Immediately after deployment, an excess pore pressure of 54 kPa was recorded. An ambient excess pore pressure of approximately 32 kPa remained after dissipation of that developed during probe installation. Because of the possible presence of gas in the sediments in this area, it is not known with certainty whether the measured excess pressure is pore water pressure, pore gas pressure, or some combination of the two. An excess pore pressure of about 32 ±4 kPa was monitored during Hurricane Eloise and...


Book ChapterDOI
JK Torrance1
TL;DR: In this paper, the pore water chemistry of low-salinity Leda clays was investigated under a variety of standard and modified storage procedures, and it was concluded that none of the storage procedures tested was entirely satisfactory.
Abstract: In recent years, the potential significance of chemical and mineralogical influences on the behavior of the post-glacial marine clays has been increasingly recognized by the soils engineering community. The precise relationships are not known, but it seems probable that, in some cases, small differences in chemical factors may explain the differences in behavior between otherwise similar samples. In connection with an investigation of these relationships, the experiments reported in this paper were undertaken to examine the magnitude of chemical change which may occur in low-salinity Leda clay during periods of storage. Pore water extraction devices are described, and the effects on the pore water chemistry of three months storage, under a variety of standard and modified storage procedures, are reported. It is concluded that none of the storage procedures tested is entirely satisfactory, in that potentially significant changes in the pore water chemistry occurred. Finally, it is recommended that pore water chemistry be assessed more often than is the present practice when soils engineering tests are performed on Leda clay and that this be done as soon as possible after the sample is obtained from the field.

Journal ArticleDOI
TL;DR: In this paper, a sample of kaolinitic clay was compacted to maximum pressures ranging from 2,000 psi (140 kg/sq cm) to 6,500 psi (455 kg/squ cm) and tested in high-pressure equipment specially designed to simulate aspects of geologic burial.
Abstract: Remolded and undisturbed samples of kaolinitic clay were compacted to maximum pressures ranging from 2,000 psi (140 kg/sq cm) to 6,500 psi (455 kg/sq cm) to observe changes in the fabric of the sample and chemistry of the expelled pore fluid. Samples were tested in high-pressure equipment specially designed to simulate aspects of geologic burial. The concentration of ions in the expelled pore water changed as compaction progressed, the major change being concurrent with the fall in pore-fluid pressure. Crystallization was present in the pores. The development of a preferred orientation clearly was associated with the level of effective stress. High pore pressures were associated with poorly oriented fabrics and incipient fissures.

31 Mar 1976
TL;DR: The strength, mode of deformation, and induced pore pressure effects of Pierre Shale have been partially investigated at 20C, at confining pressures to 2 Kb, and at strain rates of 000001/sec to 00000001 /sec.
Abstract: : The strength, mode of deformation, and induced pore pressure effects of Pierre Shale have been partially investigated at 20C, at confining pressures to 2 Kb, and at strain rates of 000001/sec to 00000001/sec All tests were performed on cylindrical samples in which bedding was parallel to the axis of maximum compression Dehydrated shale is about two and one-half times as strong as water-saturated shale Application of stress to natural (water-saturated) shale creates transient pore pressures of significant magnitude The measurement of, or control of, the induced pore pressure is one of the major experimental problems Unconsolidated shale behaves brittly at all confining pressures Consolidated shale is brittle below -200 bars, moderately brittle to -800 bars, and moderately ductile to ductile above -800 bars Failure at confining pressure below -1000 bars occurs with the formation of sharply defined brittle faults

01 Apr 1976
TL;DR: A review of case histories reveals that liquefaction failures are dependent upon a collapsible soil structure, a saturated and undrained condition, and a triggering mechanism as discussed by the authors, which is a phenomenon in which the soil mass suddenly loses shear strength, behaves as a fluid, and acquires a degree of mobility sufficient to permit large movements.
Abstract: Liuqefaction of loose, saturated, cohesionless soils is a phenomenon in which the soil mass suddenly loses shear strength, behaves as a fluid, and acquires a degree of mobility sufficient to permit large movements. This report reviews various case histories to determine common characteristics associated with liquefaction failures. A review of case histories reveals that liquefaction failures are dependent upon (a) a collapsible soil structure, (b) a saturated and undrained condition, and (c) a triggering mechanism. Typically collapsible soils which liquefied were fine, uniform, loose sand deposits with D sub 10 sizes ranging from 0.05 to 1.0 mm and a coefficient of uniformity ranging from 2 to 10. Saturated-undrained conditions provided a situation conducive to high pore pressure development upon collapse of the soil structure. Generally, water was the pore fluid; however, several unusual cases were reported with air as the pore fluid (termed fluidization). A variety of triggering mechanisms, including monotonically changing stresses, earthquakes, explosive blasts, and cyclic vibrations, were found to cause luquefaction failures. However, monotonically increasing shear stresses and earthquakes are the most common triggering mechanism. Density is the most important property controlling the susceptibility of saturated- undrained sands to liquefaction. It was found that sands which liquefy when subjected to earthquake shakings do not become significantly more stable against reliquefaction. Conversely, vibrations appear to alter the sand structure, making a deposit less susceptible to liquefaction than indicated by density increases.