Based on the operating heat-supplying tunnels in Beijing, the durability of its lining structure under the action of large thrust and thermal effect is studied. It mainly consists of two aspects, the disease composition analysis of the lining structure through ESEM-EDS and the indoor durability experiment. The field specimens' higher carbon content shown by ESEM-EDS indicated that carbonization was the main durability problem of the concrete lining structure of the heat-supplying tunnel. Considering the specific durability problem, the carbonization test of concrete under the action of temperature and stress was carried out. The results indicate that the coupling effect of high temperature- high tensile stress is the most unfavorable condition to the durability of tunnel structures. When the compressive stress increases from 0 to 0.5fc (axial compressive strength of concrete), the carbonization depth decreases. If the compressive stress increases to 0.75fc, the carbonization depth will rebound.
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