The Effect of Temperature on Prestressed Assemble Steel Struts System in Excavation

Based on the long-term monitoring of temperature and stress of two layers of pre-stressedassemble steel struts (PASS) in a large-scale excavation, the influence of temperature on the axial force ofcorner PASS during and after excavation was studied. The monitoring results showed that, during theexcavation, with the increase of earth pressure on the retaining structure and struts, the strut axial forcecaused by the temperature change increased and became the greatest after excavation. When the bottom slabwas poured and the second layer of PASS was removed, for the first layer of corner PASS, the maximumaxial force induced by the temperature change was about 5 times of that induced during the early excavation,which reached 12% of the designed axial force. After that, when the bottom slab achieved the designedstrength, for the first layer of corner PASS, the temperature effect of the strut axial force increased with theincrease of temperature. There was a linear relationship between the strut axial force induced by the unitincrease of temperature and the temperature. The strut axial force produced by the unit increase oftemperature at 30 ℃ was about 4 times of that at 5 ℃.