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Book A Comparison Between Field and Laboratory Measurements of Hydraulic Conductivity in a Varved Clay

Download or read book A Comparison Between Field and Laboratory Measurements of Hydraulic Conductivity in a Varved Clay written by DJ. DeGroot and published by . This book was released on 1994 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The measurement of hydraulic conductivity using a variety of field and laboratory techniques was evaluated at a site consisting of medium stiff and soft lacustrine varved clay in western Massachusetts. Field measurements were obtained by conducting "slug" tests in both predrilled and push-in piezometers and also from pore pressure dissipation tests using the piezocone and flat dilatometer. Laboratory hydraulic conductivity values were obtained for both vertical and horizontal flow conditions using a flexible wall permeameter and by indirect estimation from 1-dimensional consolidation tests. Based on a comparison of tests conducted throughout the profile, laboratory flexible wall tests with vertical flow gave the lowest values of hydraulic conductivity whereas the predrilled piezometers yielded the highest values. Of all the field techniques, the push-in piezometers gave the lowest values. Hydraulic conductivity values interpreted from piezocone and flat dilatometer dissipation tests tended to be between those obtained from the predrilled and push-in piezometers. Results from tests in predrilled piezometers show that the hydraulic conductivity increases with increasing screen length, showing the influence of scale effects. The results of this study clearly show that estimation of hydraulic conductivity for this soil is highly dependent on scale effects, the test technique used and on the direction of flow (i.e., parallel versus perpendicular to the orientation of the varves).

Book Hydraulic Conductivity and Waste Contaminant Transport in Soil

Download or read book Hydraulic Conductivity and Waste Contaminant Transport in Soil written by David Edwin Daniel and published by ASTM International. This book was released on 1994 with total page 617 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Comparison Between Various Field and Laboratory Measurements of the Hydraulic Conductivity of Three Clay Liners

Download or read book Comparison Between Various Field and Laboratory Measurements of the Hydraulic Conductivity of Three Clay Liners written by G. Didier and published by . This book was released on 2002 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: For waste facilities, field assessment of the hydraulic conductivity of fine- grained soils has been a real challenge for the past decades that has led to several types of test methods. Although standards (ASTM, NF, etc.) have been adopted in many countries, any test method needs careful application for constructing quality-control programs. The type of apparatus, its geometry, and even specimen preparation may be major sources of discrepancy. We compared hydraulic-conductivity values obtained from various field-testing methods (open, sealed, single and double infiltrometers, and borehole methods), and laboratory-testing methods such as oedometer cells or rigid and flexible-wall permeameters. Three materials were tested in this study: a compacted sandbentonite mixture, compacted clayey silt, and natural sandy clay. The field tests were run on soil-test pads whose characteristics were defined beforehand in the laboratory and the field. Comparison of the results shows a large range of hydraulic-conductivity values for a single soil sample. Such variability can commonly be explained by a scale effect, as demonstrated by the use of various types of diameter or geometry for the field or laboratory tests. Soil behavior (swelling or shrinkage) and test-analysis methods (saturated or unsaturated-flow analysis) are other important parameters. In conclusion, we identified the main problems affecting tests with infiltrometers and permeameters, and how they can be reduced or avoided by the improvement of current techniques.

Book A Comparison of Field and Laboratory Measurements of Hydraulic Conductivity

Download or read book A Comparison of Field and Laboratory Measurements of Hydraulic Conductivity written by A. Guerra and published by . This book was released on 1992 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydraulic conductivity of a soil was measured in the laboratory and in the field. Although each technique used yielded consistent results, the hydraulic conductivity obtained differed over several orders of magnitude. These differences in hydraulic conductivity can only be attributed to macroscopic features that weigh differently depending on the mass of soil affected by the different tests.

Book Measurement of Hydraulic Conductivity in Clay Using Push In Piezometers

Download or read book Measurement of Hydraulic Conductivity in Clay Using Push In Piezometers written by DJ. DeGroot and published by . This book was released on 1992 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydraulic performance of push-in standpipe piezometers was evaluated at a site consisting of medium stiff and soft varved clay in western Massachusetts. The results of falling head hydraulic conductivity tests performed in the piezometers were compared with results of tests performed in prebored and sand-packed piezometers and laboratory flexible wall tests performed on undisturbed samples obtained at the site. A comparison of the field and laboratory tests conducted throughout the upper portion of the profile indicates that while tests performed in the prebored piezometers generally gave hydraulic conductivity results higher than laboratory tests, results from tests performed in push-in piezometers were closer to laboratory tests.

Book Characterisation and Engineering Properties of Natural Soils

Download or read book Characterisation and Engineering Properties of Natural Soils written by T. S. Tan and published by CRC Press. This book was released on 2003 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first volume of a specialty 2-volume work contains 34 papers pertaining to the natural behaviour of diverse geomaterials found in different parts of the world. Each paper is organized along the outline: location and distribution, engineering geology, composition, state and index properties, structure, engineering properties, quality / reliability of data with reference to methods of sampling and testing, and relation to engineering problems. This extensive body of collated knowledge is integrated by three overview papers covering engineering geology, mechanical behaviour and engineering implications. Topics: Overview papers; Marine clays; Eastuarine Clays; Lacustrine clays; Stiff clays; Sands and other cohesionless soils; Residual and other tropical Soils; Weak rock.

Book The Variability and Estimation of Hydraulic Conductivity in C Horizons of Sandy Loam Glacial Till Soils Comparison of One step Outflow Laboratory Method to an I n S i t u Method for Measuring Hydraulic Conductivity

Download or read book The Variability and Estimation of Hydraulic Conductivity in C Horizons of Sandy Loam Glacial Till Soils Comparison of One step Outflow Laboratory Method to an I n S i t u Method for Measuring Hydraulic Conductivity written by Dan B. Jaynes and published by . This book was released on 1978 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Lessons Learned from the Application of Standard Test Methods for Field and Laboratory Hydraulic Conductivity Measurement

Download or read book Lessons Learned from the Application of Standard Test Methods for Field and Laboratory Hydraulic Conductivity Measurement written by RJ. Dunn and published by . This book was released on 1994 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Standard ASTM test methods are now available for laboratory and field measurements of hydraulic conductivity of compacted clay soils which are used in liners and covers at waste facilities. They are widely used in waste facility design and construction quality assurance. Many of these methods require input of qualified professionals to select appropriate test parameters. Unless the parameters are carefully selected, conflict may arise over the suitability of test results and thus the regulatory acceptance of a liner or cover. Four case histories are presented which illustrate the use of both laboratory and field test methods and some of the variations which may result. These variations can usually be explained in terms of test parameters, but they emphasize the importance of suitable engineering judgement for careful selection of test conditions, and data reduction methods which are appropriate for to site conditions and allow for comparison of test results from various tests.

Book Cone Penetration Testing

Download or read book Cone Penetration Testing written by Paul W. Mayne and published by Transportation Research Board. This book was released on 2007 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: NCHRP synthesis 368 explores the current practices of departments of transportation associated with cone penetration testing (CPT). The report examines cone penetrometer equipment options; field testing procedures; CPT data presentation and geostratigraphic profiling; CPT evaluation of soil engineering parameters and properties; CPT for deep foundations, pilings, shallow foundations, and embankments; and CPT use in ground modifications and difficult ground conditions.

Book Comparison of Laboratory and Field Methods for Determining the Quasi Saturated Hydraulic Conductivity of Soils

Download or read book Comparison of Laboratory and Field Methods for Determining the Quasi Saturated Hydraulic Conductivity of Soils written by and published by . This book was released on 1997 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory and field ponded infiltration tests in quasi-saturated soils (containing entrapped air) exhibit the same three-stage temporal variability for the flow rate and hydraulic conductivity. However, the values for the hydraulic conductivity may differ by as much as two orders of magnitude due to differences in the geometry and physics of flow when different laboratory and field methods are applied. The purpose of this paper is to investigate this variability using a comparison of results of ponded infiltration tests conducted under laboratory conditions using confined cores, with results of field tests conducted using partially isolated cores and double-ring infiltrometers. Under laboratory conditions in confined cores, during the firs stage, the water flux decreases over time because entrapped air plugs the largest pores in the soils; during the second stage, the quasi-saturated hydraulic conductivity increases by one to two orders of magnitude, essentially reaching the saturated hydraulic conductivity, when entrapped air is discharged from the soils; during the third stage, the hydraulic conductivity decreases to minimum values due to sealing of the soil surface and the effect of biofilms sealing the pores within the wetted zone. Under field conditions, the second stage is only partially developed, and when the surface sealing process begins, the hydraulic pressure drops below the air entry value, thereby causing atmospheric air to enter the soils. As a result, the soils become unsaturated with a low hydraulic conductivity, and the infiltration rate consequently decreases. Contrary to the laboratory experiments in confined cores, the saturated hydraulic conductivity cannot be reached under field conditions. In computations of infiltration one has to take into account the variations in the quasi-saturated and unsaturated hydraulic conductivities, moisture and entrapped air content, and the hydraulic gradient in the quasi-saturated or unsaturated soils.

Book Canadian Geotechnical Journal

Download or read book Canadian Geotechnical Journal written by and published by . This book was released on 2009 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt: