REN Lianwei,HAN Zhipan,HUO Jiwei,et al.Field Test on Thermal Response of Large Diameter Energy Pile under the Pile Top Constraint[J].Journal of Disaster Prevention and Mitigation Engineering,2022,42(05):937-944.
REN Lianwei,HAN Zhipan,HUO Jiwei,et al.Field Test on Thermal Response of Large Diameter Energy Pile under the Pile Top Constraint[J].Journal of Disaster Prevention and Mitigation Engineering,2022,42(05):937-944. DOI: 10.13409/j.cnki.jdpme.20210118001.
Field Test on Thermal Response of Large Diameter Energy Pile under the Pile Top Constraint
Energy pile is a new green technology, in line with the concept of energy conservation and emission reduction in engineering construction and green development. In order to study the thermodynamic properties and structural response of energy piles of large diameters, a heat exchange pipe was buried in the large-diameter cast-in pile under the bearing platform to form an energy pile at the site of national G310, Lingbao city, Henan Province, 2×2 pile group foundation of Didong abutment. Field tests on the thermal response of energy piles without loading in summer were carried out to measure outlet and inlet temperature, stress, residual temperature after return temperature, temperature change-thermally induced stress/axial force relationship and pile top displacement during operation of energy piles. The test results show that the temperature and stress of the pile increased slightly with the increase of flow rate under three different flow rate tests. After stopping the test, the residual temperature was still 16%-28% after 5 days of reheating, while the residual temperature after 7 days was about 11%-17%. The maximum stress along the pile was about 3.5 MPa. The cumulative deformation of the pile tip of the energy pile was -0.98mm (about 0.81‰ of the pile diameter). The values of Kh of pile top were 28.6%, 37.8%, 43.2% and 71.4% respectively under different conditions of single pile no-load, no-load cap pile group constraint, single pile step-by-step loading, and constant load cap pile group constraint, showing an increasing trend. The
q
A
at the flow rate of 0.6 m/s and 0.8 m/s was 53% and 128% of
q
A
at the flow rate of 0.4 m/s.
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