青藏铁路路基中正融土斜坡稳定性分析

Analysis of Stability of Thawing Slopes on Roadbed of Qing-tibet Railway

冻土斜坡稳定性问题出现于20世纪50年代的极地地区,青藏铁路的建设,提出了高原地区斜坡稳定性课题。目前,常用的有5种正融土斜坡稳定性分析的方法,均以极限平衡法为依据。根据分析认为,Pufahl[1]的分析方法比较适合高原地区的正融土斜坡稳定性。该方法认为,冻土斜坡失稳的主要原因归咎于土中的孔隙水压力。水压力包括以下3个主要方面,即渗透压力、由自重引起的固结压力和融化固结引起的固结压力。笔者利用非饱和理论,引用孔隙水压力P1和孔隙气压力P2表达在冻土边坡稳定性分析中,提出用相应的冻土斜坡稳定性分析方法。

Analysis of the stability of thawing slopes began in1950s at polar area. Construction of Qing-tibet railway raises this topic concerning plateau area. In goaeral there are five approaches to calculate the thawing slope stability, all of which refer to the method of limitation equilibritrn. According to analysis, the metthod of Pufahl is more preferable to be used on plateau area. Pufahl that the instable factors in thawing slope are attributed to the pore water pressure which consists three parts, nattily, osmotic pressure , consolidation pressure due to the self weight or due to external applied load, and consolidation pressure due to thaw-consolidation. Applying the theory of unsaturated soil, the pore water pressure （P1） and pore air pressure （P2） are introduced into the analysis of thawing slopes.