Investigation of Shallow Failure of a Highway Slope Constructed over Expansive Soil

Highway slope constructed with high plastic clay soils are subjected to repetitive shrinkage and swelling behavior due to the cyclic wet-dry season which usually softens over the time and initiates failure after few years of construction. The shrinkage cracks also act as conduits for rain water intrusion which may reduce the strength of the soil and initiates surficial movement of the slope. During this study, failure of a highway slope located in Fort Worth, Texas was investigated and the effect of rainfall over the slope failure is evaluated. The failure of the slope was investigated using the soil testing boring, laboratory testing, slope stability analysis and an unsaturated flow analysis. The site investigation included samples collection from different depth of borings, determination of the soil index properties as well as strength parameters from different shear strength tests. The obtained test results were further utilized in slope stability and flow analysis using the finite element method (FEM) in PLAXIS. The study indicates that both fully soften condition and rainfalls are responsible for the failure of slope. The fully soften condition provided factor of safety 1.46 whereas with perched water condition after rainfall, the factor of safety became 1.05.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AFP10 Engineering Geology. Alternate title: Investigation of Shallow Failure of Highway Slope Constructed over Expansive Soil.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Khan, Mohammad Sadik
  • Hossain, MD Sahadat
  • Ahmed, Asif
  • Faysal, Mohammad
• Conference:
  • Transportation Research Board 94th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2015-1-11 to 2015-1-15
• Date: 2015

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References; Tables;
• Pagination: 19p
• Monograph Title: TRB 94th Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Expansive clays; Highways; Rainfall; Slope failure; Slope stability; Slopes; Weather conditions
• Geographic Terms: Fort Worth (Texas)
• Subject Areas: Geotechnology; Highways; I42: Soil Mechanics; I51: Earthworks and Soil Drainage;

Filing Info

• Accession Number: 01551113
• Record Type: Publication
• Report/Paper Numbers: 15-5481
• Files: TRIS, TRB, ATRI
• Created Date: Jan 27 2015 11:21AM