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用透水土工布包裹道砟碎石填筑的截排水纵向盲沟,是哈尔滨-大连高速铁路(简称哈大高铁)在大开挖路堑段采用的重要的防冻胀工程措施.由于碎石层在顶部温度较低时,其中发生对流换热过程而强化对其下部土体的降温作用,可能导致盲沟底部冻结而影响其防冻胀效果.通过数值仿真软件分析了排水盲沟的温度状况,结果表明:对于哈大高铁的气温环境,在不考虑积雪影响的条件下,将发生盲沟底部排水管冻结积冰,影响纵向盲沟防冻胀效果的问题.在盲沟顶土层中加设0.1 m保温板能够提高盲沟底部的最低温度,推迟起始冻结时刻,缩短冻结时长,但不能完全避免盲沟底部排水管的冻结问题.在有表层保温板的条件下,在盲沟底部换填砂层虽然不能提高盲沟碎石层的温度,但却能有效提高盲沟底部的温度.复合措施可以有效解决盲沟底部冻结的问题.
Longitudinal blind cut of cut-off water filled with permeable geotextile wrapped shingle gravel is an important anti-frost expansion engineering measure adopted by Harbin-Dalian High Speed Railway in the large cutting section. When the temperature at the top is low, the convective heat transfer process intensifies the cooling effect on the lower soil, which may cause the bottom of the blind ditch to freeze and affect the anti-frost heaving effect.The numerical simulation software analyzes the temperature condition of the blind ditch, and the result The results show that for the temperature environment of Harbin-Dalian high-speed railway, without affecting the influence of snow, the ice accumulation at the bottom of the blind ditch will occur, which will affect the anti-frost heaving effect of the vertical blind ditch. The 0.1 m thermal insulation board can raise the minimum temperature at the bottom of blind ditch, postpone the initial freezing time and shorten the freezing time, but can not completely avoid the freezing problem of the drain pipe at the bottom of the blind ditch. Although the sand-filling layer can not raise the temperature of the blind-gravel layer, it can effectively raise the temperature of the bottom of the blind channel, and the composite measures can effectively solve the problem of freezing at the bottom of the blind channel.