新型管幕冻结法在河堤防渗加固中的温度场分析

Temperature field analysis of new pipe curtain freezing method in river embankment anti seepage reinforcement

为了探究新型管幕冻结法是否能够对河堤进行有效的防渗加固,利用有限元软件基于温度场对新型管幕冻结法在防渗固堤中的应用展开研究,设置4条分析路径,对冻土帷幕的基本情况和各路径的冻结效果特征进行分析。结果表明:冻土帷幕自冻结管处形成后向周围蔓延,从第8天起,0.5 m深度上侧的冻土帷幕发展开始“加速”,相较于另一侧冻土帷幕,其发展更快、强度更高、冻结更密实。冻结完成后,0.5 m深度上侧冻土帷幕均匀密实,坡面上温度最低可降至-25.34℃,各观测点温度均在-24℃以下,最终冻结温度和降温速率均呈现出“M”形特征;堤面最快可在第11天开始冻结,在第14天冻土覆盖整个堤面,土体最终冻结温度与深度之间呈指数函数关系。管幕钢管边界冻结差异较大,最高温点与最低温点温度分别为-24.94℃和-2.89℃,相差约22℃,冻土帷幕最小厚度约0.78 m。所得结果可为将来的相关实际工程提供参考依据。

In order to explore whether the new pipe curtain freezing method can effectively strengthen the river embankment,this paper uses the finite element software to study the application of the new pipe curtain freezing method in antiseepage and embankment reinforcement based on the temperature field,and sets up four analysis paths to deeply analyze the basic situation of the frozen soil curtain and the freezing effect characteristics of each path.The results show that the frozen soil curtain spreads around after it is formed at the freezing pipe.From the 8th day,the development of the frozen soil curtain on the upper side of 0.5 m depth begins to “accelerate”.Compared with the frozen soil curtain on the other side,it has faster development,higher strength and denser freezing.After freezing,the frozen soil curtain on the upper side of 0.5 m depth is uniform and dense;the minimum temperature on the slope can be reduced to-25.34℃,and the temperatures at each observation point are below-24℃.The final freezing temperature and cooling rate show “M”type characteristics.The embankment surface started to freeze at the earliest on the 11th day,and the frozen soil covered the whole embankment surface on the 14th day.The relationship between the final freezing temperature and depth is an exponential function.There is a great difference in the freezing of the steel pipe boundary of the pipe curtain.The highest temperature point and the lowest temperature point are-24.94℃ and-2.89℃ respectively,with a difference of about 22℃.The minimum thickness of the frozen soil curtain is about 0.78 m.The obtained results can provide reference basis for relevant practical projects in the future.