青藏铁路多年冻土地区碎石护坡路基非线性分析

NUMERICAL ANALYSIS OF RAILWAY EMBANKMENT PROTECTED WITH ROCK FILLS IN PERMAFROST REGION OF QINGHAI AND TIBET

为了研究碎石护坡对冻土区路基温度场的影响,以青藏铁路试验段现场观测的气候和地质资料为上边界条件,运用带相变瞬态温度场有限元数值解法,对不同厚度的碎石护坡路基进行了分析。结果表明:粒径为10 cm的碎石护坡对多年冻土区路基的稳定性有保护作用;碎石护坡对路基坡脚附近地温影响较大,采用碎石护坡对防止路基纵向裂缝的产生有一定的作用;实际应用中碎石层厚度不能太厚。

To study the influence of the crushed rock slope protection on the temperature field of the embankment in permafrost region, finite element analysis is conducted, in which phase changes are taken into consideration to simulate the embankment with crushed rock slope protection layer of different thickness and the observation data of the climate and geological conditions in Qinghai - Tibet railway testing section are used as the upper boundary condition. The calculation results show that the crushed rock slope protection can enhance the stability of the embankment in permafrost region. The influence the crushed rock creates to the temperature field is relatively great near the toe of the embankment, and the crushed rock slope protection can prevent the embankment from longitudinal cracks to some extent. In practice, the thickness of the crushed rock layer can not be too thick.