次生不良冻土对路基稳定性影响的数值分析

The Numerical Analysis of the Impact of the Secondary Harmful Frozen Soil on the Subgrade Stability

研究目的:多年冻土区修筑路基工程会形成次生不良冻土现象,次生不良冻土对铁路、公路路基等建筑物会产生各种危害。研究多年冻土区不良冻土现象的形成机理和发育对防治次生不良冻土的发生和发展,保证工程的稳定和安全有着非常重要的意义。本文通过对次生不良冻土现象中的热融滑坍进行数值分析并提出次生灾害的防治及工程的保护措施。研究结论:本文对多年冻土区次生不良灾害的形成机理及变化过程进行研究,得出如下结论:(1)路基的阴坡和阳坡之间存在热差异,在吸收热量时路基阳坡融化深度比阴坡融化深度要大,阴阳坡效应对路基融化深度的影响是不容忽视的;(2)考虑热融沟渗流作用的影响时路基横向的不均匀变形会加剧,从而会形成路基纵向裂缝的病害,严重影响路基的稳定性;(3)本文为在多年冻土地区的工程建设提供了一定的理论依据,对防治次生不良冻土灾害具有参考意义。

Research purposes： In permafrost regions, secondary harmful frozen soil phenomena can be formed by constructing subgrade engineering, and the secondary harmful frozen soil has many harmful impacts on buildings such as railway, highway roadbed. Studying the formation mechanism and development of the adverse phenomenon about frozen soil in permafrost regions has very important significance for controlling the happening and development of the secondary harmful frozen soil, and at the same time for guaranteeing the stability and safety of the engineering. In this article, we put forward the prevention of secondary disasters and engineering protection measures by analysising the thaw - frozenlandslide in secondary harmful frozen soil phenomena. Research conclusions：In this paper, we studied the formation mechanism and changing process of secondary harmful frozen soil in permafrost regions and got the following conclusions： （1）Thermal differences exist between shady slope and sunny slope of roadbed, melting depth in sunny slope is bigger than shady slope when absorbing heat, and the effect of shady and sunny slope on the depth of roadbed melting cannot be ignored ; （2） Considering the seepage effect, roadbed transverse inhomogeneous deformation will increase, which will form the disease of roadbed longitudinal cracks and have serious influence on the stability of the roadbed; （3） In this paper, we provide some theoretical foundations about the engineering construction in permafrost regions, which have reference meaning for controlling the secondary harmful frozen soil.