哈尔滨-齐齐哈尔客运专线路基防冻工程模型试验研究

Model test study on the anti-frost engineering along the Harbin-Qiqihar Passenger Dedicated Railway

季节冻土地区修筑铁路客运专线面临着严重的路基冻胀问题,为研究保温板(XPS)在季节冻土地区路基工程中的防冻胀效果,开展了室内模型试验研究.试验结果表明:经过2个周期的试验,保温板上下温差十分明显,保温板上下温差在负温期高于正温期,保温板下土体冻结速率随保温板厚度的增加而减小.30 cm保温板下黄土的含水率随冻融过程呈单一变化规律,其他3个试验模型土体含水率在冻结开始时先减小,冻结结束时增大,最终保持稳定的趋势.4个试验模型中的下层土体冻胀量均远大于上层土体,无保温板黄土试验模型冻胀量远大于其他3个保温板试验模型;AB料冻胀量随保温板厚度的增加而减小,AB料冻胀率远小于黄土冻胀率.因此,在季节冻土地区路基设计中宜采用保温板路基,路基填料优先采用AB料.

In seasonally frozen soil regions, the construction of passenger dedicated railway meets severe frost heaving problem. A laboratory model test was carried out to investigate the anti-frost effect of XPS insulation board. The test result shows that the temperature difference between upside and downside of an insulation board is obvious after two test cycles. The temperature difference between the upside and downside of an insulation board is higher in negative air temperature period than that in positive air temperature period. The freezing rate below the insulation board decreases with insulation board thickness. The moisture content variation with time is monotonous for the model of loess model with 30-cm insulation board. For the other three models, the moisture content decreases at the beginning of freezing and increases at the end of freezing, and keeps stable finally. For all four test models, the frost heaving of the deeper soil is far larger than that of the shallow soil. The frost heav- ing of the loess model with no insulation board is far larger than that of the other three models with insulation board. The frost heaving of AB group filling material decreases with thickness of insulation board. The frostheaving rate of the AB group filling material is smaller than that of loess. As conclusion, insulation board and AB group filling material are suggested to apply in the railway design in seasonally frozen soil regions.