寒区工程锅盖效应病害调查与防治研究进展

Engineering Diseases Investigation and Research Progress on Prevention of the Pot-cover Effect in Cold Regions

寒区大温差环境下封闭工程结构层覆盖于地基上,导致水分聚集在结构层底部形成“锅盖效应”,引起地基承载力降低,加剧工程冻融病害。随着“一带一路”的推进,寒区高等级公路、油气站场、机场跑道建设涉及的锅盖效应病害亟需解决。调查了寒区公路路基、高铁无砟轨道基床、机场跑道、输油站场面临的锅盖效应病害,从病害特征、形成机理、理论模型、防控技术等四个方面,综述了寒区工程锅盖效应形成机理及病害防治的最新进展。同时,在总结当前锅盖效应研究不足的基础上,提出了今后寒区工程锅盖效应理论研究和灾害控制措施的方向:①关注水汽含量的测试和多年冻土区锅盖效应形成条件研究;②构建考虑空气-水汽两相流和土体变形规律的水-汽-热-力耦合模型,以此来预测工程构筑物的稳定性;③开展基于“阻-通-截”理念的综合防治措施研究,以期为寒区工程设计和病害防治提供理论支持和科学对策。

In the cold regions with large temperature difference,covering the closed structure layer on the foundation will lead to the accumulation of water and vapor at the bottom of the surface layer,which will form the“pot-cover effect”,thereby reducing the bearing capacity of the foundation and aggravating the freezing-thawing disease of the construction projects.With the promotion of“the Belt and Road”,the research on the prevention technique measures of pot-cover effect diseases involving the high-grade highways,oil and gas stations and airport runways in cold regions is urgently needed.Based on the investigation of the diseases caused by the pot-cover effect on highway subgrade,subgrade bed of ballastless track of high-speed railway,airport runway and oil transfer station,the latest progress of the formation mechanism and prevention measures of pot-cover effect of engineering in cold regions from four aspects:disease characteristics,formation mechanism,theoretical model and prevention technology was summarized.Meanwhile,the disadvantages of the current study on pot-cover effect were summarized.Finally,the challenges for future research on the mechanism of the pot-cover effect and disaster control measures were put forward:pay attention to the test of water vapor content and the research on the formation conditions of the pot-cover effect in permafrost regions;establish a coupled water-vapor-heat-stress model which considering the flow of air and vapor and soil deformation characters to predict the stability of engineering structures;carry out comprehensive prevention and control measures based on the principle of“resistance-passage-interception”.These suggestions will provide theoretical guidance and scientific basis for the wide engineering design and hazard control in cold regions.