人工冻结软土融沉对埋地管道影响的模型试验研究

Experimental study on influence of artificial frozen soil thawing on buried pipes

为研究冻土地区埋地管道在融沉过程中的受力机理,利用人工冻融技术,开展了人工冻结饱和软黏土中埋地管道融沉模型试验,测试研究了融沉过程中土体温度场、水分场、位移场分布情况以及管道的力学特性。结果表明:在融沉过程中,土体的沉降主要由融化沉降和压缩沉降两部分组成;通过控制冷端温度可以有效的控制融沉速率,土体融化后,土中应力则主要集中于荷载区域下方土体,并且随着深度的增加荷载对土体的应力出现衰减;随着管道通热,冻土层的解冻,管身在油温作用下产生热膨胀现象,同时荷载对管身的作用也愈加明显,管身出现向下挠曲和圆截面椭圆化现象。结果对于冻土融化时管道的安全评估具有意义。

In order to study the stress mechanism of the buried pipeline in the frozen soil area during the thawing process,the artificial freezing and thawing technology was used to carry out the thawing model test of the buried pipeline in the artificially frozen saturated soft clay,and the test studied the distribution of soil temperature field,moisture field,displacement field and the mechanical characteristics of the pipeline during the thawing process.The result shows that the settlement of the soil body is mainly composed of melting settlement and compression settlement during the process of melting settlement.By controlling the temperature of the cold junction,the melting rate can be effectively controlled.After the soil melts,the stress in the soil is mainly concentrated in the soil below the load area,and as the depth increases,the stress of the load on the soil decreases.As the pipeline is heated and frozen soil thaws,the tube body expands under the action of oil temperature,at the same time,the effect of the load on the pipe body becomes more and more obvious resulting in downward deflection and elliptical circular cross section of the pipe body.The results are of great significance to the safety assessment of the pipeline when the frozen soil is melting.