青藏工程走廊公路路基热影响数值分析

NUMERICAL ANALYSIS FOR ROADBED HEAT INFLUENCE IN QINGHAI—TIBET ENGINEERING CORRIDOR

青藏工程走廊内构造物的热影响规律对新建构造物选线和工程的稳定具有重要意义。采用考虑相变的控制方程和有限单元法,以相同的温度边界为前提,以公路路基高度和宽度为影响因素,对青藏工程走廊路基热影响规律进行研究。结果显示,路基的热影响范围对路基高度和宽度有很高的敏感性,路基宽度与其热影响范围呈正相关性,在高度均为1.5 m的情况下,宽8 m的路基热影响范围比宽21.5 m的路基热影响范围小5 m(50 a后);路基高度与其热影响范围呈负相关性,在宽度均为21.5 m的情况下,高1.5 m的路基热影响范围比高5 m的路基热影响范围大2.3 m(50 a后)。热影响范围也明显受到阴阳坡的影响,在同一时间点上,阳坡端的热影响范围要明显大于阴坡端。而保温板在一定程度上可以起到缩减路基热影响范围的作用,但是这种作用比较有限。

The heat influence law for structure in Qinghai—Tibet engineering corridor is significant to the new path selection of structure and keeping old structure stable. On the basis of same temperature boundary condition,taken height and width of embankment as impact factor,control equation which involved phase change and finite element method was applied,and heat influence law along the Qinghai—Tibet engineering corridor were studied. Results indicate that heat influence limit of embankment is highly sensitive to height and width of embankment. Width is positively correlated with heat influence limits while height is negatively correlated with. After 50 years,with the same height of 1.5 m,heat influence limit of 8 m wide embankment is 5 m smaller than that with 21.5 m wide embankment;with the same 21.5 m width,heat influence limit of 1.5 m high embankment is 2.3 m bigger than that with 5 m high embankment. And heat influence limits is obviously affected by north and south slopes effect：heat influence limits at south side is distinctly bigger than that at north side at the same time. Insulation board can weaken heat influence limits to some extent,but the effect is limited.