青藏线路基纵向裂纹形成和扩展的机理

Mechanism of the Longitudinal Crack Formation and Growth in the Embankment of Qinghai-Tibet Road

在多年冻土地区,尤其是高含冰量的多年冻土区,阴阳坡的出现给路基的稳定性带来了极大的危害。路基两侧往往出现了大量的纵长宽大裂缝,部分裂缝甚至贯穿路基。本文通过对路基现场温度进行监测分析,得出路基纵向裂纹形成的原因是路基下的冻土融沉引起路基应力场重新分布;借助断裂力学定性的分析了裂纹在路基内部的扩展趋势,定性分析的结果与现场的路基剖面图是一致的,最后就裂纹今后的扩展的趋势和有可能的危害进行初步预测。

When road water content, the is constructed in permafrost region of long time, especially with rich stability of embankment is dramatically imperiled by the ＂Yin-Yang＂ slope. As a result, a myriad longitudinal cracks appear along each side of the road, and some of the them even penetrate through the roadbed. By observing the site temperature data of the embankment, we get that the stress field is redistributed in the embankment because of the thaw of permafrost. The authors adopted fracture mechanics to qualitatively analyze the crack growth trend in the interior of embankment. Such analysis is consistent with the scene profile of the embankment. In addition, the trend of crack growth and the potential harm could be predictive by the means.