ISSN: 1945-7545
CODEN: GTJODJ
Page Count: 6

Theoretical Evaluation of the Transient Response of Constant Head and Constant Flow-Rate Permeability Tests

Zhang, M
Geological Survey of Japan, Tsukuba, Ibaraki,

Takahashi, M
Geological Survey of Japan, Tsukuba, Ibaraki,

Morin, RH
United States Geological Survey, Denver, CO

Esaki, T
Faculty of Engineering, Kyushu University, Fukuoka,

Abstract

A theoretical analysis is presented that compares the response characteristics of the constant head and the constant flow-rate (flow pump) laboratory techniques for quantifying the hydraulic properties of geologic materials having permeabilities less than 10⁻¹⁰ m/s. Rigorous analytical solutions that describe the transient distributions of hydraulic gradient within a specimen are developed, and equations are derived for each method. Expressions simulating the inflow and outflow rates across the specimen boundaries during a constant-head permeability test are also presented. These solutions illustrate the advantages and disadvantages of each method, including insights into measurement accuracy and the validity of using Darcy's law under certain conditions. The resulting observations offer practical considerations in the selection of an appropriate laboratory test method for the reliable measurement of permeability in low-permeability geologic materials.

Keywords:
low permeability, hydraulic gradient, theoretical analyses, constant head, flow pump, permeability test

Paper ID: GTJ10425J
DOI: 10.1520/GTJ10425J
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