Study of pile behavior by improvement of confining soils using frustum confining vessel

Document Type: Research Note

Authors

1 Department of Civil and Environmental Engineering, Amirkabir University of Technology, AUT, Tehran, Iran

2 Department of Civil and Environmental Engineering, Amirkabir University of Technology, AUT, Tehran, Iran.

Abstract

A physical modeling apparatus made at Amirkabir University of Technology (FCV-AUT), called Frustum Con ning Vessel, is employed to determine the eff ects of soil improvement on piles performance. The FCV-AUT is capable of linearly modeling the existing overburden stresses in the eld. Three types of Babolsar sand with relative densities between 20% and 70% were examined in these tests. Results of compression and tensile
load tests on seven piles, with the embedment length to diameter ratio (D/B) of 9, were used to evaluate the e ects of soil improvement methods of soil densi cation as well as postgrouting on the piles performance. The results show that the increased bearing capacity by soil compaction from loose to medium state is greater than that of the medium to dense state. This increase has been observed to be a function of pile construction methods and pile tip conditions. Also, tip and/or side post-grouting enhanced the performance of bored
and concrete precast piles by increasing soil-pile interaction and its bearing capacity. The results of pile load tests carried out on the FCV-AUT have been observed to be well-aligned with the static bearing capacity calculations based on the API method.

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