Citation: | CHEN Long, HU Yifan, CHEN Yonghui, ZHU Lei, ZHANG Tilang. Centrifuge Test on Bearing Capacity of Energy Piles in Sand Affected by Thermal-Cool Cycles[J]. Journal of Southwest Jiaotong University. doi: 10.3969/j.issn.0258-2724.20220740 |
To study the bearing capacity of energy piles in sand affected by thermal-cool cycles, a centrifuge model test on slender energy piles buried in Fengpu sand with different compactions was carried out. The change rules of the axial force, side friction, and individual bearing capacity of energy piles were obtained and compared under 20 thermal-cool cycles in the test. The test results show that the axial force of the energy pile decays gradually and tends to be stable with increasing thermal-cool cycles. The maximum axial force attenuation value of the energy pile buried in the sand with medium compaction is much larger than that buried in the dense sand. During thermal-cool cycles, for energy piles buried in the sand with medium compaction, a neutral point is located at the bottom half of the pile. Positive additional side friction is generated above the neutral point during cool cycles, and negative additional side friction is generated underneath the neutral point. Oppositely, during thermal cycles, negative additional side friction appears above the neutral point, and positive additional side friction is underneath the neutral point. The dense sand has an obvious constraint effect on the lower part of energy piles. Positive additional side friction is distributed along the pile during cool cycles because the pile moves downward relative to the surrounding soil. During thermal cycles, the additional side friction is negative. The bearing capacity of the energy piles will be reduced because of the long-term temperature cycles. The bearing capacity of the energy piles buried in the dense sand and sand with medium compaction is reduced by 7.3% and 15.6%, compared with the prototype pile. The bearing capacity of the prototype pile and energy piles buried in the dense sand is 11% larger than that of the prototype pile buried in the sand with medium compaction. Therefore, reasonable measures should be taken to meet the bearing requirements of energy piles when buried in sandy layers with different compactions in actual engineering.
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