00621789

Component

http://onlinepubs.trb.org...trr/1991/1309/1309-003.pdf

https://scholar.google.co...lson&publication_year=1991

Innovations in laboratory methods for hydraulic-conductivity measurements have been developed by using a flow pump to generate a constant rate of flow through a test specimen and monitoring the hydraulic gradient induced thereby with a differential-pressure transducer. In most applications of this constant-flow method to date, hydraulic-conductivity tests have been conducted on stress-controlled specimens following conventional loading increments in one-dimensional consolidometers and also after increments of three-dimensional consolidation in triaxial cells. Similarly, a constant rate of flow through one end of a test specimen has been generated with a flow pump while flow through the opposite end of the specimen is driven to or from a pressure-controlled reservoir. More recent innovations include a new flow-pump actuator that enables identical flow rates to be infused and withdrawn from opposite ends of a test specimen and the use of additional flow pumps to control the effective stress and volume of a specimen. These innovations provide a convenient approach for obtaining hydraulic conductivity versus effective stress data in triaxial cells on a wide variety of materials, including sandstones and shales that cannot be trimmed and mounted in fixed-ring permeameters or one-dimensional consolidometers. These innovations also provide a means to integrate constant-flow hydraulic conductivity measurements with continuous-loading consolidation tests on fully saturated specimens in both back-pressured consolidometers and in triaxial cells.

This paper appears in Transportation Research Record No. 1309, Geotechnical Engineering 1991. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

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p. 9-17

1991

Transportation Research Record

0309051185

Figures (13) ; Photos (1) ; References (21)

Actuators; Control; Effective stress; Flow; Innovation; Laboratory tests; Measurement; Permeability coefficient; Sandstones; Shale; Specimens; Triaxial shear tests; Volume

Flow rate; Triaxial testing machine

Geotechnology; Highways; I42: Soil Mechanics

TRIS, TRB

Apr 30 1992 12:00AM

• APPLICATION OF CONTINUOUS DYNAMIC COMPACTION CONTROL FOR EARTHWORKS IN RAILROAD CONSTRUCTION
• BROADENING THE SPECIFICATION OF GRANULAR FILLS
• CORRELATING RESILIENT MODULI FROM PRESSUREMETER TESTS TO LABORATORY CALIFORNIA BEARING RATIO TESTS
• DECISION SUPPORT SYSTEM FOR EVALUATION AND TREATMENT OF EARTH SLOPE INSTABILITY
• FINITE ELEMENT ANALYSIS OF PARTIALLY SATURATED SEEPAGE THROUGH COMPACTED FILLS
• INEXPENSIVE AUTOMATIC CONTROL SYSTEM FOR SOILS TESTING
• LABORATORY CORRELATION STUDY OF NEAR-SURFACE RESPONSE PARAMETERS
• MEASUREMENT OF SHEAR AND COMPRESSION WAVES DURING TRIAXIAL TESTING
• PROTOTYPE GEOTECHNICAL INFORMATION SYSTEM
• SEISMIC SPECTRA FOR HIGHWAY BRIDGES IN WASHINGTON STATE
• USE OF VOICE-RECOGNITION SYSTEMS FOR ATTERBERG LIMIT TESTS