冻结井自然解冻规律与壁间注浆机理分析

    Analysis of natural thawing law of freezing well and mechanism of grouting between walls

    • 摘要: 冻结井自然解冻情况是选择合理壁间注浆时机的依据,以淮北煤田临涣矿区袁店二矿西风井为工程背景,采用现场实测与数值计算方法研究冻结壁在解冻过程中温度场时空演化规律,并给出合理的壁间注浆时机。结果表明:在自然解冻过程中,冻结温度场升温过程分为低温快速升温阶段、相变缓慢升温阶段以及正温快速升温阶段;在冻结壁冻结界面上径向距离4~10 m范围内,−135 m细砂层在负温升温阶段平均温度的升温速度为0.075 ℃/d,−150 m黏土层的升温速度为0.063 ℃/d,−215 m黏土层的升温速度为0.074 ℃/d,−241 m钙质黏土层的升温速度为0.067 ℃/d;在负温升温阶段,有效冻结壁平均温度上升较快,相变阶段、正温升温阶段冻结壁的平均温度上升较慢;细砂地层冻结壁的融冻比为1.32~1.48,黏土地层融冻比为1.49~1.73;冻结壁解冻期间,在冻胀力以及土水压力协同作用下,冻结井内外层井壁之间产生径向的反方向弹性位移,双层井壁之间间隙增大,从而为壁间注浆浆液扩散提供了通道,因此,在冻结壁完全解冻,压力水作用下壁间间隙已经形成,内壁还没有出水前注浆效果较好。

       

      Abstract: The natural thawing condition of the frozen well is the basis for selecting a reasonable time for inter-wall grouting. Taking the west wind well of Yuandian No.2 Mine in Linhuan Mining area of Huaibei Coal field as the engineering background, the spatio-temporal evolution of the temperature field of the frozen wall during the thawing process is studied using field measurement and numerical calculation methods, and a reasonable time for inter-wall grouting is given. The results show that: in the natural thawing process, the warming process of the freezing temperature field is divided into low temperature rapid warming stage, phase transition slow warming stage and positive temperature rapid warming stage. In the range of 4−10 m radial distance on the freezing interface of the freezing wall, the average temperature rise rate of −135 m fine sand layer during the negative temperature rise stage is 0.075 ℃/d. The heating rate of −150 m clay layer is 0.063 ℃/d. The heating rate of −215 m clay layer is 0.074 ℃/d. The temperature rise rate of −241 m calcareous clay layer is 0.067 ℃/d. The average temperature of the effective freezing wall rises faster in the negative temperature and temperature rise stage, while the average temperature of the freezing wall rises slowly in the phase transition and positive temperature and temperature rise stage. The freeze-thaw ratio of the fine sand formation is 1.32−1.48. The ratio of thawing to freezing in clay strata is 1.49−1.73. During the thawing of the frozen wall, under the synergistic action of frost heave force and soil-water pressure, the radial and reverse elastic displacement occurs between the inner and outer layers of the frozen well, and the gap between the double walls increases, thus providing a channel for the diffusion of grouting slurry between the walls. Therefore, when the frozen wall is completely thawed and the gap between the walls is formed under the action of pressure water, the grouting effect is better before the inner wall is discharged.

       

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