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| Coupling analysis of temperature field test and secondary lining structure stress field of long tunnel in alpine and high altitude area#br# |
（1. School of Materials Science and Engineering, Chang′an University, Xi′an, Shaanxi 710061, China; 2. Xi′an Municipal Facilities Management Center, Xi′an, Shaanxi 710016, China; 3. China Communications Second Highway Engineering Bureau Co., Ltd., Xi′an, Shaanxi 710065, China)
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Abstract Taking a tunnel in Tibet as research object, the change law of temperature field in the tunnel site area was monitored and analyzed. Selecting 9 test sections, the temperature of tunnel depth, the temperature of surrounding rock, the temperature of each section and the contact pressure of the secondary lining structure were respectively measured. Based on the test results, the finite element software of ABAQUS was used to simulate and analyze the stress field of the tunnel lining structure. The results show that the annual temperature and the daily temperature of tunnel change periodically with time in sinusoidal curve, and the air temperature along the tunnel depth shows the change law of "rapid increaseslow increasestabilization". The temperature of section closer to the entrance of tunnel changes more obviously, and the temperature tends to be stable with the increasing of the depth of surrounding rock. The decreasing sequence of temperature change of each part for tunnel entrance section is vault, pavement and side wall, while more than a certain depth, the temperature change of each part in descending order is pavement, vault and side wall. The contact pressure distribution of the second lining is greatly affected by the horizontal tectonic force, which exhibits the characteristics of inward extrusion. The second lining structure of the tunnel entrance section is mostly affected by the temperature difference. When the daily temperature difference is more than 15 ℃, the actual temperature stress accounts for 4.0% of the total stress on the secondary lining structure, and the repeated force caused by temperature difference accounts for 71.3% of the design value of "code for design of concrete structures" of GB 50010—2010, which illuminates that antifreeze and heat preservation measures should be taken in time.
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Received: 18 October 2019
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