高寒冻融区高速铁路路堑工程温度场特性分析

Analysis of Temperature Field Characteristics of High Speed Railway Cutting in Extremely Cold Freeze⁃thaw Areas

以高寒冻融区牡丹江—佳木斯高速铁路沿线典型的路堑工程为研究对象,通过现场试验、数值模拟和理论分析相结合的手段,研究了寒区高速铁路路堑工程温度场随时间演化的一般特性,分析了积雪覆盖对基床水热状态的影响,讨论了影响路堑边坡失稳的因素。结果表明:路堑的冻结过程为自上向下的单向冻结,而融化过程分别为自上向下和从下向上的双向融化;厚积雪覆盖会对基床起到保温作用,有利于降低最大冻结深度,但融雪水的入渗将导致基床产生峰值冻胀或翻浆冒泥病害;寒区边坡的失稳滑塌主要发生在冻融交界面处。为保证深季节冻土区高速铁路的长期服役性能,建议在基床表层铺设防渗吸热材料(沥青混凝土封闭层)来控制基床的总冻胀量。

Taking the typical cutting works along the Mudanjiang-Jiamusi high speed railway in the high-cold freezethaw area as the research object,the general characteristics of the temperature field of the high speed railway cutting works in the cold area with time evolution were studied by means of a combination of field test,numerical simulation and theoretical analysis.The influence of snow cover on the water-thermal state of subgrade was analyzed,and the factors affecting the instability of the cutting slope were discussed.The results show that the freezing process of cutting is one-way freezing from top to bottom,while the thawing process is a top-down and bottom-up two-way thawing respectively.Thick snow cover will have a thermal insulation effect on the subgrade and help reduce the maximum freezing depth.However,the infiltration of snowmelt water will cause peak frost-heave or mud-pumping disease in the subgrade.The instability and collapse of slope in cold area mainly occurs at the interface of freezing and thawing.In order to ensure the long-term service performance of the high speed railway in the deep-seasonal frozen soil area,it is recommended to lay anti-seepage and heat-absorbing materials(asphalt concrete sealing layer)on the surface of the subgrade to control the total frost-heave of the subgrade.