Published Online: 1 August 2012
Page Count: 12
Alfaro, Marolo C.
Professor, Dept. of Civil Engineering, Univ. of Manitoba, Winnipeg,
Pathak, Yadav P.
Geotechnical Engineer, EBA, A TetraTech Company, Vancouver,
(Received 24 March 2010; accepted 25 May 2012)
This paper reports results from bench-scale plane-strain laboratory tests conducted in order to investigate the behavior of geogrid-reinforced silt specimens during freezing and thawing cycles. Soil–geogrid interaction was analyzed through comparison of the soil and geogrid strains. Vertical and lateral pressures were applied to the specimens to simulate anisotropic loading conditions in the field. Reinforced and unreinforced specimens were subjected to cycles of freezing (−25°C) and thawing (+23°C) temperatures inside a walk-in temperature-controlled environmental chamber. Measured geogrid strains at the end of 12 freezing-thawing cycles were on the order of 0.57 %. An additional strain of this magnitude in the reinforcement due to the freezing-thawing cycles would have only minimal effect on working strain levels in the design, which range from 1 % to 2 %. However, the strains induced by freezing and thawing can approach working design strains as the number of cycles increases. This could have significant long-term implications if accumulated strains were to overstrain the geogrid. The soil deformations were observed to be mostly horizontal. This pattern of deformations during the freezing and thawing of silt could result in shallow sliding at the face of slopes and embankments. The soil strains were higher than the geogrid strains, indicating relative movements between soil and reinforcement, mostly during thawing.
Paper ID: GTJ103101