American Society of Civil Engineers


Monitoring In Situ Soil Moisture Variations of Expansive Clay Using Neutron Probes


by Jie Li, (School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476V, Melbourne, VIC 3001 Australia. E-mail: jie.li@rmit.edu.au) and Gang Ren, (School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476V, Melbourne, VIC 3001 Australia. E-mail: gang.ren@rmit.edu.au)
Section: Section 4: In Situ Testing, pp. 341-346, (doi:  http://dx.doi.org/10.1061/41106(379)43)

     Access full text
     Purchase Subscription
     Permissions for Reuse  

Document type: Conference Proceeding Paper
Part of: Deep Foundations and Geotechnical In Situ Testing
Abstract: The neutron probe has proven to be an effective means for long-term monitoring of in-situ soil moisture variations. However, correlation of neutron probe data (i.e. neutron counts) with moisture contents to give accurate absolute values is a very difficult task, particularly for expansive soils due to problems associated with soil volume changing and shrinkage cracks. In this study, a numerical model of neutron diffusion in soils is used to calibrate neutron-probe data collected in a field site over a period of 5 years. The envelopes of soil moisture content derived from the neutron probe, representing the extreme observation at various depths are reported. The effects of tress and covers on soil moisture changes are also examined.


ASCE Subject Headings:
Soil water
Monitoring
Expansive soils
Clays