填土高度对冻融区填石通风路基沉降变形的影响分析

Impact Analysis of Earth-filling Height on the Settlement Deformation of Rock-filled Ventilation Roadbed in Freeze-thaw Zone

本文针对新藏公路高海拔冻融区填石通风路基不均匀沉降病害频发问题,充分考虑该地区气温、太阳辐射、风速以及“阴阳坡”等边界条件,建立热-力耦合有限元数值模型,研究了填土高度分别为0.5、1.5、3.5 m时,填石通风路基的沉降特性。结果表明:冻融区道路不同位置温度场存在较大差异,阳坡侧温度全年最高,温度远高于其他位置,天然地面与阴坡侧温度较低。提高填石通风路基上侧填土高度能够改善道路前期沉降问题,如3.5 m填土高的路基沉降差仅为0.5 m填土高的1/3倍,对应的横向沉降差仅为1.16 m,但过高的填土由于“阴阳坡”效应易导致路基产生较大的不均匀沉降。

In response to the frequent occurrence of uneven settlement diseases in the high-altitude freeze-thaw zone of the Xinjiang-Tibet Highway.A thermal-mechanical coupled finite element numerical model was established by taking into account boundary conditions such as temperature,solar radiation,wind speed,and"sunny-shady slope".The settlement deformation characteristics of the rock-filled ventilation roadbed were studied when the filling heights were set as 0.5 m,1.5 m,and 3.5 m,respectively.The results indicate that there are significant differences in the temperature field at different locations of roads in the freeze-thaw zone.The highest temperature on the sunny slope side throughout the year is much higher than other locations,and the temperature on the natural ground and the shaded slope side is lower.Increasing the height of the earth-filling on the upper side of the ventilation roadbed can improve the settlement problem in the early stage of the road.For example,the roadbed settlement difference of a 3.5 m earth-filling is only 1/3 times that of a 0.5 m earth-filling,and the corresponding lateral settlement difference is only 1.16 m.However,excessive earth-filling height can easily cause significant uneven settlement of the roadbed due to the"sunny-shady slope"impact.