冻土融沉对路面结构力学响应的影响

Effect analysis of thaw settlement of permafrost on mechanical responses of pavement structure

为研究冻土融沉规律及其对沥青路面结构的影响,结合青藏高原地区实测温度数据,运用数值模拟技术研究多年冻土地区路基温度场变化特性,分析特定温度场条件下冻土路基融沉规律,再以该融沉曲线为路面结构的位移边界,计算了路面结构的融沉附加应力,并与无融沉时的结构响应进行了比较。研究结果表明:冻土路基从表面逐渐向内融化,当外界温度较低时,路基土内部还存在冻土核,当外界温度足够高时,则路基土内部可能全部融化;当融深较大时,固结沉降较大,反之则较小;冻土路基融沉变形曲线近似于抛物线形状,回归建立了路基融沉变形公式,而在此位移边界条件下,路面结构产生附加应力,会对结构产生不利影响。

In order to study the thaw settlement of permafrost and its effect on the asphalt pavement ac- cording with the actual data of temperature in Tibet, the characteristics of subgrade temperature field in permafrost region and the thaw settlement of subgrade under the specific temperature field were studied by numerical analysis, and the extra-stress of pavement structure was calculated by taking the thaw settlement curve as the displacement boundary which was compared with that without thaw settlement. The results show that the permafrost subgrade thaws from surface, and there is a frozen core when the temperature is lower outside, but the permafrost subgrade may thaw en- tirely when the temperature is higher. The thaw settlement and consolidation are bigger when the thaw depth is deeper, and vice versa. The curve of thaw settlement and consolidation is similar to a parabola, and the regression formula can also be established. Under the displacement boundary of thaw settlement, the surface structure produces an extra-stress which is a serious adverse im- pact on pavement structure. 3 tabs, 11 figs, 8 refs.