Study on Degradation in Axial Bearing Capacity of a Cast-in-Situ Pile Caused by Sulfate Attack in Saline Area
Sulfate ions attack cast-in-situ piles of bridges and roads and hence deteriorate their bearing capacities. A theoretical model is proposed for evaluating the bearing capacity of a cast-in-situ pile under sulfate corrosive condition. Evolution rules of the side resistance, the end resistance, the bearing capacity, the strength of pile body, as well as the compressive rigidity and the flexural rigidity are studied systematically. The effects of pile diameter and length on the bearing capacities are analyzed and compared in detail. Studies show that the side resistance of pile is influenced by both radial compressive stress redistribution and concrete deterioration caused by accumulating of sulfate corrosion products. And it is also influenced by length and diameter of the pile. The end resistance and the effective area decrease with the increase of sulfate corrosion depth. The strength of pile body decreases rapidly during sulfate corrosion process. Both the compressive and flexural rigidities show remarkable drops with the increase of corrosion depth. The results show that increasing the pile diameter can enhance the pile’s resistance against corrosion and slow the decline in its bearing capacity.
KeywordsSulfate saline soil Cast-in-situ pile Corrosion mechanism Bearing properties Evolution rules
This research was supported financially by the National Natural Science Foundation of China (No. 41772290) and the Project of Shaanxi Province (No. 20170522).
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