Unsaturated Hydraulic Properties and Suction Variation on a Pavement Subgrade Over Expansive Soil

Selection of unsaturated flow parameters offers quite a challenge while conducting numerical modeling. Incorporation of unsaturated permeability and flow parameters is usually laboratory based while it represents a specific condition of the soil which is unable to capture the real time scenario of field. The objective of the study was to determine the variation of unsaturated hydraulic conductivity based on rainfall response data. In addition, a novel approach was undertaken to determine the unsaturated flow parameters from field soil water characteristic curves during the study while it is quite common to conduct laboratory testing and determine the parameters by curve fitting. For this study, two 2-lane roads in Kaufman County and Ellis County, Texas were selected for data acquisition and monitoring. Soil moisture and suction sensors were installed up to 4.5 m depth to monitor in-situ moisture content, matric suction and rain gauges were installed to record the precipitation at the sites. Finally, the field obtained data was transferred in PLAXIS 2D environment for transient flow analysis. The validity of the estimated parameters was confirmed, as FE results corresponded with direct field measurements. Analysis showed that change in suction at shallower depths recorded considerable variations. The study results indicated that FE modeling can provide effective information about the subgrade matric suction variation.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AFP60 Standing Committee on Engineering Behavior of Unsaturated Geomaterials.
• Authors:
  • Ahmed, Asif
  • Hossain, Md Sahadat
  • Khan, Mohammad Sadik
• Conference:
  • Transportation Research Board 97th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2018-1-7 to 2018-1-11
• Date: 2018

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References; Tables;
• Pagination: 21p

Subject/Index Terms

• TRT Terms: Hydraulic properties; Soil suction; Subgrade (Pavements); Swelling soils; Unsaturated soils
• Geographic Terms: Ellis County (Texas); Kaufman County (Texas)
• Subject Areas: Geotechnology; Highways; Hydraulics and Hydrology; Pavements;

Filing Info

• Accession Number: 01657891
• Record Type: Publication
• Report/Paper Numbers: 18-04297
• Files: TRIS, TRB, ATRI
• Created Date: Jan 25 2018 9:33AM