饱和软黏土中埋地管道冻结模型试验研究

Experimental study on freezing model of buried pipeline in saturated soft clay

为研究软土地区埋地管道在土体冻结过程中的管道受力机理,开展了饱和软黏土中地埋管道冻结模型试验。通过人工冻结技术,近似还原了管土受冻过程,研究了人工冻结过程中土体温度场、水分场、位移场分布情况,以及管道的力学特性。结果表明:在冻结过程中,土体温度场的变化直接影响着土中水分场的分布;在冻结锋面前缘存在着剧烈的水分迁移现象,大量的水分向冻结锋面迁移,使得土体产生线性冻胀;冻胀发展速率受外部荷载的直接影响;当冻结发展到管道处时,位于冻胀和非冻胀过渡段位置处的管身出现应力最大值。研究结果对于正冻土中管道的安全评估具有重要的意义。

In order to study the mechanisms of pipeline stress in the process of soil freezing in soft clay area,in this paper,the freezing model test of buried pipeline in saturated soft clay was carried out,and the temperature field,water field and displacement field of soil during artificial freezing,as well as the mechanical properties of the pipe,were studied. The results show that:(1)During the freezing process,the change of soil temperature field directly affects the distribution of soil water in the soil;(2)There is a strong water migration phenomenon in front of the freezing front,and a large amount of water migrates to the frozen front,causing linear frost heaving of the soil;(3)The rate of development of frost heaving is directly affected by external loads;(4)When the freezing develops to the position of the pipe body,the pipe body at the position of the frost heaving and unfrozen transition section exhibits a maximum stress. The results of the study are useful for the safety assessment of pipelines in normal frozen soil.