New Vacuum-Preloading Technique for Ultrasoft-Soil Foundations Using Model Tests
Publication: International Journal of Geomechanics
Volume 17, Issue 9
Abstract
The effectiveness of vacuum preloading is a very important aspect of the improvement effect of dredger fill. This study experimentally investigated this issue using four different vacuum-preloading methods with a physical model test. The ultrasoft soil was obtained from Tianjin, China, and the samples were prepared in a slurry state using a physical model testing device. The samples were subjected to the traditional vacuum-preloading method and three modified vacuum-preloading methods (multistaged vacuum preloading, vacuum preloading with intermittent ventilation, and vacuum preloading with air injection and intermittent ventilation), in which the water discharge amount, rate of water discharge, amount of settlement, and pore-water pressure were analyzed as well. The results indicate that, under the vacuum preloading with air injection and intermittent ventilation mode, the water discharge amount increased faster, and the final discharge volume was greater than that obtained under the other methods. Meanwhile, the variation trend characterizing the settlement was similar to that of the water discharge amount, where the relative settlement under the vacuum preloading with air injection and intermittent ventilation mode was approximately 1.8 times that under the traditional vacuum-preloading method for the Tianjin hydraulic fill foundation. In addition, the results for the water content and dry density indicated that the vacuum-preloading method with air injection and intermittent ventilation was more effective than the other vacuum-preloading methods in terms of improvement in the Tianjin, China, area.
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Acknowledgments
This investigation was funded and supported by the National Natural Science Foundation of China (Projects 51378344 and 51578371) and the Tianjin Technical Xinghai Project (KJXH2013-15). Their support is greatly appreciated.
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Published In
International Journal of Geomechanics
Volume 17 • Issue 9 • September 2017
Copyright
© 2017 American Society of Civil Engineers.
History
Received: Aug 2, 2016
Accepted: Feb 7, 2017
Published online: May 4, 2017
Published in print: Sep 1, 2017
Discussion open until: Oct 4, 2017
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