多年冻土区铁路路基沉降变形研究与思考

Studying and Thinking on the Settlement and Deformation of Railway Roadbed in Permafrost Regions

根据青藏铁路路堤、路堑过渡带冻土路基分层沉降变形现场监测资料,笔者分析了路基变形的来源及机理。研究结果表明,路堑段,路基沉降变形主要来源于路基换填土层的固结变形;零填段,路基沉降变形主要来源于路基基底以下至原冻土上限之间活动层的压密变形;路堤段,路基沉降变形主要来源于高温-高含冰量冻土在较高附加应力作用下产生的压缩及蠕变变形,该变形在目前尚无明显衰减趋势,且相同时期各层沉降量明显比路堑段及零填段大,必须引起注意;最后从国内外研究现状讨论了系统开展高温-高含冰量冻土区路基变形研究的必要性和紧迫性。

Based on the field data of the layered roadbed settlement observed during the construction of the transitional section from cut to fill along the Qinghai-tibetan railway, this paper discusses the sources and mechanism of roadbed deformation. Analysis of the observational resuh shows：（1） In the cut section, the deformation was mainly caused by the consolidation of the soil-replacing layer;（2） In the cut-to-fill location, most of the deformation was from the consolidation of the original active layer;（3） In the fill section, the deformation mostly resulted from the compression and creep of the warm and ice-rich frozen soil under the original permafrost table because of the additional stress of the higher embankment. The settlement of the embankments has no obvious trend of attenuation at present. Moreover, the deformation in the fill section is greater than that in the cut section and the cut-to-fill location. Therefore, much consideration must be given to this problem. Finally, this paper points out the necessity and urgency to study the roadbed deformation in the warm and ice-rich permafrost regions based on the state-of-the-art of the warm and ice-rich frozen soils at home and abroad.