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Instrumentation to Measure Soil Subsidence and Water Content in a Single Borehole
Author(s) -
Neely Haly L.,
Ackerson Jason P.,
Morgan Cristine L. S.,
McInnes Kevin J.
Publication year - 2014
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2014.02.0055n
Subject(s) - borehole , water content , soil water , soil science , repeatability , instrumentation (computer programming) , soil horizon , environmental science , geology , swell , geotechnical engineering , remote sensing , chemistry , oceanography , chromatography , computer science , operating system
Errors associated with current methods for measuring in situ vertical soil shrinkage related to water loss are associated with measurements being spatially disconnected, which introduces unknown spatial variability and excessive soil disturbance during installation. To minimize these errors, a method was developed to measure changes in thicknesses of multiple soil layers in a single borehole. Soil layer thickness was measured by tracking the location of magnets in the sidewall of the borehole using a probe with a magnetic field sensor. The sensor was capable of submillimeter repeatability for measurements of soil layer thickness. Soil water content was measured with a neutron moisture meter in the same borehole. Measurements made on two soils showed that, compared with spatially separated measures, the single borehole method improved the observed relationship between soil shrink‐swell and water content change, increasing r 2 from 0.73 to 0.90.