关键词: 白垩系地层, 冻结壁, 温度场, 水化热, 现场实测, 数值模拟

Abstract: Because of very thick water-rich cretaceous strata covered on the seam of Ningzheng coal field, the freezing method is often applied to construct rockshaft. Due to the insufficient research on extension features of the freezing temperature field and the range influence of the frozen wall caused by hydration heat, some problems will exist such as the unreasonable freezing design and the inaccurate time prediction for the closure of freezing wall. Based on the wind well of Xinzhuang mine in Ningzheng coal field, field measurement and numerical simulation have been carried out to study the characteristics of freezing temperature field distribution and influence of outer shaft wall concrete hydration heat. The results show as fellows: temperature falling fast at early freezing, the average rate of freezing can reach to 0.23 ℃/d; the development rate of freeze front reaches to 21.08 mm/d; the affect of concrete hydration heat on the temperature field of the frozen wall by side wall is serious, and the melting depth range of the frozen wall can reach 440-480 mm；the temperature of 3# measuring point from outer wall 50 mm rises 33.6 ℃ with the average heating rate achieving to 2.6 ℃/d. Results by comparing the numerical simulation and field test show that parameter values are basically identical, such as expansion rate of Sandstone freezing wall and well temperature, which can well predict the temperature field variation of frozen wall.

Key words: cretaceous stratum, frozen wall, temperature field, hydrated heat, actual measurement, numerical simulation