Evaluating the Behavior of Laterally Loaded Piles under a Scoured Condition by Model Tests

Abstract

Abstract Scour removes soil around piles supporting waterfront structures and changes the behavior of laterally loaded piles from flow wave, earthquake, and wind. Limited experimental studies have been conducted so far on the behavior of laterally loaded piles under a scoured condition. To evaluate their behavior under a scoured condition, model tests of laterally loaded piles were conducted in this study to investigate the effects of the scour depth, scour slope, and scour width under both static and repeated loading. Total of 41 tests were conducted in this study. For the static loading phase, the scour depth ranged from 0 to 500 mm with a 100-mm increment and a test was conducted for each scour depth. The scour slope ranged from 0 to 30 degrees with a 15-degree slope increment and for each slope increment four tests were conducted with scour depths ranged from 200 to 500 mm. The scour widths were 0, 240, 400, and 667 mm and for each scour width four tests were conducted with scour depths ranged from 200 to 500 mm. On the other hand, only three tests were conducted to investigate the effect of the scour depth, scour slope, and scour width under repeated loading. The scour depths were 200 and 400 mm, the scour slopes were 0 and 30 degrees, and the scour widths were 0 and 667 mm. Two-way loading was the method of applying repeated loads and a safety factor of 2.0 was applied for the ultimate lateral load capacities of the piles calculated using Broms' method. Pile failure was defined when the lateral displacement at the point where the lateral load was applied reached 20% the diameter of the pile. The static loading test results showed that the ultimate lateral load capacities from the experimental work were close to those obtained from Broms' method. The ultimate lateral load capacities decreased significantly as the scour depth increased. At the same scour depth, the increased scour slope increased the ultimate lateral load capacities for the pile. Furthermore, at a constant scour depth, the increased scour width decreased the ultimate lateral load capacities for the pile. On the other hand, the repeated loading test results showed that the lateral displacement at the point where the lateral load acted was decreased as the scour depth and the scour width increased. Furthermore, the results also showed that the lateral displacement at the point where the lateral load acted increased as the scour slope increased.