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根据青海省共(和)玉(树)高速公路特殊结构路基的地温监测资料,对3种路基(XPS保温板路基,碎石路基和通风管路基)填土与地基土的地温变化情况及冻土人为上限变化与天然上限附近热流密度状况以及路基温度场的非对称性进行对比分析,研究3种路基的地温分布特征及降温效果。测试结果表明:(1)3种路基在左、右路肩的不同深度处均呈现出明显的升温趋势,观测期内,XPS板路基升温幅度最大;碎石路基次之,通风管路基最小;(2)路基修筑完成初期,3种路基的多年冻土人为上限均存在不同程度抬升;到第3年,3种路基下多年冻土人为上限均下降;(3)3种路基的冻土上限附近热量收支均呈吸热状态,吸热量大小顺序为XPS板路基>碎石路基>通风管路基;(4)3种路基内部温度均呈左高右低的不对称分布。综上研究结果,建议在今后高温冻土区的高速公路建设中优先采用通风管路基。同时,为减小地温不均匀分布造成的路基纵向裂缝等病害,路基的横断面应采取差异化设计的原则。
According to the ground temperature monitoring data of the special structure subgrade of Gonghe (He) (Jade) Highway in Qinghai Province, the paper analyzes the change of the ground temperature and the frozen ground of three subgrade (XPS insulation board subgrade, crushed stone subgrade and ventilation pipe embankment) The aboriginal people conducted a comparative analysis of the heat flux density and the asymmetry of the temperature field in the vicinity of the natural upper bound, and studied the distribution characteristics of the ground temperature and the cooling effect of the three subgrade types. The test results show that: (1) The three kinds of roadbed show obvious warming trend at different depths of the left and right shoulders. During the observation period, the maximum temperature rise of XPS board roadbed is followed; 2) In the initial stage of embankment construction, the artificial upper limit of permafrost of the three types of subgrade are raised in varying degrees; by the third year, the artificial upper limit of permafrost under the three kinds of subgrade decline; (3) Near the upper limit of permafrost The heat balance was in an endothermic state, and the order of heat absorption was XPS board embankment> crushed stone embankment> ventilation pipe embankment. (4) The internal temperature of the three kinds of embankment showed an asymmetric distribution of left high right and low. Based on the research results, it is suggested that ventilating pipe subgrade be preferentially used in the construction of expressway in permafrost regions in the future. At the same time, in order to reduce the longitudinal cracks and other diseases caused by the uneven distribution of ground temperature, the principle of differential design should be adopted for the cross section of roadbed.