Comparison of soil strength measurements of agricultural soils in Nebraska. (June 2018)

• Record Type: Journal Article
• Authors: Wieder, Wendy; Shoop, Sally; Barna, Lynette; Franz, Trenton; Finkenbiner, Catherine
• Is Part Of: Journal of terramechanics. Volume 77(2018)
• Page Start: 31
• Page End: 48
• Publication Date: 2018-06
• Subjects: Agricultural soils -- Soil strength -- Bearing capacity -- DCP -- CI -- CIH -- LWD -- Soil water content; a loading plate diameter [mm] -- CBR California Bearing Ratio [%] -- CI cone index [psi] -- CIH Clegg Impact Hammer -- CIV Clegg Impact Value -- d0 deflection at the center geophone [mm] -- COSMOS Cosmic-Ray Soil Moisture Observing System -- CRNP Cosmic-Ray Neutron Probe -- d0(r) deflection at the geophone located at distance r from the center of the plate -- DCP dynamic Cone Penetrometer or Dynamic Cone Penetrometer Index [mm/blow] -- E Young's modulus [MPa] -- E0 elastic modulus from the center geophone [MPa] -- E(r) elastic modulus from the geophone located at distance r from the center of the plate [MPa] -- f contact stress distribution factor -- FWD Falling Weight Deflectometer -- LWD Lightweight Deflectometer -- MC soil moisture content [g/g, %] -- r distance from the center of the plate [mm] -- V Poisson's ratio of the soil -- σ0 stress under the plate [MPa]; Trafficability -- Periodicals; Praticabilité (Routes) -- Périodiques; Trafficability; Periodicals; 629.222
• DOI: 10.1016/j.jterra.2018.02.003
• Languages: English
• ISSNs: 0022-4898

Abstract

Highlights: Soil strength and water content were measured for three agricultural fields. The light weight deflectometer (LWD) was compared to other standard field strength tests. The LWD results compared best with the Dynamic Cone Penetrometer and Clegg Impact Hammer. Soil water contents were determined both remotely and from soil samples. Correlations showed some effect of soil water content on soil strength. Abstract: In 2014 the University of Nebraska, Lincoln (UNL) was engaged in field testing program to investigate a soil moisture mapping system as a crop management tool. In conjunction with this work, the US Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory (ERDC-CRREL) deployed a team to perform soil characterization and strength measurements at three agricultural test sites. The primary objective was an investigation of the Lightweight Deflectometer (LWD) as a soil surface strength tool for the purposes of assessing bearing capacity of soft soils. The LWD measurements were performed with those from more "standard" tests, i.e. the Dynamic Cone Penetrometer, Cone Penetrometer, and Clegg Impact Hammer to determine if the LWD produced results that compared with these methods. The strength test data were also used to calculate California Bearing Ratio (CBR) values using existing equations in order to see if the different test methods produced similar CBR values that could in turn be used to predict the bearing capacity of the sites. The secondary objective was to compare the strength data with the corresponding soil water content data taken by UNL to determine if soil moisture was an indicator of soil strength.