高温管线-含气土热传导与液气渗流耦合作用机理及灾变调控

我国沿海地区广泛分布含游离状微气泡的含气土。沿海地区油气管道、埋地电缆等高温管线设施经常不可避免地穿越含气土地基，由于其高压缩、低强度和温度敏感性，含气土地基往往是整条线路中受力最复杂、最易发生屈曲、断裂等灾变的区段。保障含气土地基中高温管线长期安全服役成为土木、能源领域的重要课题。.本项目基于单元体试验探究温度对含气土渗流和变形特性的影响，建立考虑温度效应的渗流模型和变形本构关系；进一步结合本构理论、渗流和传热学理论，构建含气土固-液-气-热耦合作用及其与高温管道相互作用模型，提出考虑温度效应的管土相互作用分析方法，开展高温管道-含气土相互作用离心模型试验，深入揭示含气土热传导-液气渗流-骨架变形耦合机理，并提出考虑温度效应的管线长期服役性能评估方法和调控措施。本项目提出地基热水气力耦合效应对管道服役性能影响研究新思路，将丰富管土相互作用理论，为管线服役性能评估及灾变调控提供科学支撑。

Gas-bearing soils with free microbubbles are widely distributed in the offshore areas whose seepage and strength characteristics are sensitive to the temperature change. High temperature pipeline facilities for oil transportation and underground cables in the offshore areas inevitably pass through the gas-bearing soils where tend to be the area with the most complex stress and highest risk of disaster owing to its high compressibility, low strength and sensitivity to temperature. Thus, the research of thermo-hydro-mechanical coupling mechanism in gas-bearing soils around high temperature pipeline has become an important topic in the fields of civil engineering and energy engineering..Based on the test study of the temperature effect on the seepage and strength characteristics of soil, the seepage model and constitutive relation considering the temperature effect are established. By combining with the constitutive equations of soils, fluid flow theory and heat transfer theory, the thermo-hydro-mechanical coupling model in gas-bearing soils is built and the analytical method of the pipe-soil interaction considering temperature effect is presented. The centrifuge modeling test of the interaction of high temperature pipeline and gas-bearing soils is carried out to reveal the coupling mechanism of heat transfer, fluid flow and soil deformation. The evaluation method and control measures of the long-time service performance of the pipelines considering temperature effect will be further brought forward. The research to be carried out will establish a new idea to study the effects of hydro-thermal coupling effect of soils on the service performance of the pipelines, and will develop the theory of pipe-soil interaction greatly, which will provide a scientific support for evaluating the service performance of the pipelines.