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不同渗流速度对新型管幕冻结法温度场影响

Effects of seepage on new pipe curtain freezing method

  • 摘要: 为了探究渗流作用对新型管幕冻结法温度场发展与分布规律的影响,利用有限元软件研究不同渗流速度下冻结施工中冻结帷幕的发展规律,通过分析冻结壁的交圈时间与最终厚度,得出如下结论:渗流对冻结帷幕的影响主要体现在冻结施工前期冻结壁未交圈时,以及渗流作用对上游的冻结帷幕影响较下游更显著,导致冻结帷幕产生向下游的偏移;冻结壁交圈后能发挥较好的止水作用,冻结区域内渗流速度几乎为0;渗流对温度场的影响体现在使冻结壁交圈时间推迟与使冻结壁厚度变薄,随着渗流速度增加,冻结帷幕交圈闭合时间延长呈现非线性,可采用指数函数进行拟合;上游与冻结方向平行处冻结壁最薄,冻结帷幕与渗流方向垂直处几乎不受到渗流影响,在渗流速度过大时,冻结帷幕交圈时间会大幅增加,可采用加密上游冻结管的方式减小渗流对冻结区域的影响,分析结果可为后续类似工程提供参考依据.

     

    Abstract: In the report, in order to explore the effects of seepage on the development and distribution of the temperature field of the new pipe curtain freezing method, the finite element software was used to analyze the change law of the frozen curtain in freezing construction with the different seepage velocity, the circle time and the final thickness of the frozen wall were analyzed. The results showed that the influence of seepage on the freezing curtain is mainly reflected in the early stage of freezing construction when the freezing wall is not crossed, and the influence of seepage on the upstream freezing curtain is more significant than that on the downstream, which results in the deflection of the freezing curtain to the downstream; after the freezing wall is crossed, it can play a better role in stopping water, and the seepage velocity in the freezing area is about 0; the influence of seepage on the temperature field is reflected in the delay of the freezing wall cross-loop time, and with the increase of seepage velocity, the freezing curtain cross-loop closure time is extended non-linearly, and which can be fitted by exponential function; the freezing wall is thinnest at the upstream parallel to the freezing direction, and the freezing curtain is almost unaffected by seepage at the direction perpendicular to the direction of seepage outside the normal curtain. Under the too much seepage velocity, the cross-loop time the frozen curtain increases significantly. Encrypting the upstream freezing tube can decrease the effects of seepage on the frozen areas. Our findings can provide a reference for some similar projects.

     

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