Author(s): Li Feng; Zhang Xiaopeng; Gao Tai; Chen Kai
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Keywords: No Keywords
Abstract: In order to meet the need of static ice pressure analysis for hydraulic structures, a series of compression tests of freshwater ice are carr ied out under low strain rates, to determine their failure modes and corresponding ult imate loads. The test specimens are w ith a same crosssect ion (25mm (cid: 117) 50mm) but different lengths (100mm, 360mm and 500mm). D isplacement rate of the testing machine is controlled within 0.005~0.1 mm/min. There are total 29 specimens are used under axial loading and eccentr ic loading condit ions. Some air bubbles and tiny cracks are included in some specimens which are used for examining the flaw effect. These tests show that there are two kinds of failure modes: compressive fracture and creep buckling. Creep buckling is dominant for the conditions with fewer flaws, higher temperature, bigger eccentricity, as well as low strain rate. Crit ical strain rate is about 3.34×10 (cid: 16) 7 s-1. The normal strengths under failure loads with creep buckling are far lower than those with compressive fracture. These results suggest that under spot condit ions o f nature ice cover, the dominant failure mode should be creep buckling with which the maximum stat ic ice pressure is reached. Air bubbles do not badly influence failure loads except ing when they are concentrated distribution. It is also d iscovered that, under ult imate failure condit ions after creep buckling, bearing capacity for axial force of a specimen increases with increasing bending moment.
Year: 2010