Study on the influence law of hydration heat of concrete in outer wall of frozen well on frozen wall

Abstract

In order to obtain the influence law of hydration heat of concrete on the frozen wall, the freeze-thaw condition of the frozen wall during concrete pouring in the outer wall of Dongfeng well in Huaibei Qingdong Coal Mine was analyzed by field measurement and numerical calculation, and the results show that the freezing wall heated up rapidly within 10 days after concrete pouring, and the freezing wall reached the maximum thawing depth; the heat of hydration heats up the well wall of the frozen wall of the clay layer to more than 20 ℃, and the heating range is more than 25 ℃. The maximum thawing depth of the clay layer is 334-358 mm, and the maximum thawing depth of the clay layer is 4.0-4.5 times that of the fine sand layer. Under the normal cooling condition of the frozen hole, the thawing frozen wall was refrozen after pouring concrete for 26 days, so the concrete had sufficient positive temperature curing time, which will not affect its early strength. There is a nonlinear exponential function between the temperature of concrete in the shaft wall and the thawing depth of the frozen wall. The polystyrene foam board between the frozen wall and the shaft wall can effectively reduce the influence of the hydration heat of the shaft wall concrete on the frozen wall in the deep stratum, and ensure that the freezing wall will not melt too deep due to the influence of hydration heat, thus effectively ensuring the strength and stability of the frozen wall in the construction process.

Keywords

• freezing sinking method
• frozen wall
• concrete hydration heat
• thawing depth
• numerical calculation