UBC Theses and Dissertations
Large scale pullout testing of geosynthetics Muthu, Raju D.
An evaluation of soil-geosynthetic interface friction is important to the design of any anchorage detail of a reinforced soil structure or membrane-lined waste containment facility. A large pullout apparatus has been designed and commissioned to evaluate the mobilization of pullout resistance in geosynthetic test specimens. Sand samples were prepared by pluviation into a rectangular box, 1.30m x 0.64m x 0.60m. A stress controlled top boundary was used to apply vertical stresses in the range 5 to 90 kPa. A rate of pullout displacement of 0.5 mm/min was used in the program of testing. A technique of strain gauging the geosynthetic test specimen has been developed. Variables examined in the program of testing were type of geosynthetic and confining stress. Measurement of pullout force, pullout displacement, horizontal pressure on front face of the test box, strain in geosynthetic material, water pressure in the surcharge bag, and volume change were taken during testing. Pullout resistance increases with confining stress and is described by a bond factor or a bond coefficient. Some test specimens failed in pullout, and some were tending toward tensile yield. A development of progressive strain was observed.
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