The inner and outer surfaces of concrete lining in deep alluvium freezing shaft are exposed to different temperatures, taking the hydration heat of cement for pyrogen. Additional stresses are therefore observed in concrete lining, owing to its marked temperature drop at early ages. This paper makes a numerical calculation of the temperature and the thermal stress on freezing shaft lining by finite element methods and engineering monitoring. The results reveal that the concrete of shaft lining has a high heat-release rate in the early age. And the time when shaft lining reaches its maximum temperature is 4 days earlier than it reaches its maximum thermal tension stresses. At the time of one day after the shaft lining pouring, the inner and outer surface of shaft lining will crack owing to its hoop tension strain is greater than ultimate tension strain. The crack of concrete will increase with the modifications of temperature.
Based on the theory of viscoelasticity and the principle of interaction between surrounding rock and structure in unload state, analytical solution of the stress field and displacement field of the frozen wall is obtained. Calculation results of the stress and displacement fields suggest that radial stress and displacement in the sidewall are very large within 15 days after pouring concrete of the outer shaft wall, which is proved by the fact that engineering incidents such as shaft wall rupture happen exactly at this time. The results also indicate that radial stress at different points in frozen wall all tend to the imposed loads on outer frozen wall finally, and that means the frozen wall is fluidized. This calculation theory can be used in the design of frozen wall in deep alluvium.
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