Settlement of embankments in permafrost regions in the Qinghai-Tibet Plateau
Settlement of embankments in permafrost regions in the Qinghai-Tibet Plateau
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DOI：
10.1080/00291950701409249
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发表时间：
2007-06
期刊：
影响因子：
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通讯作者：
Q. Jilin;Shengsong Yu;Z. Jianming;W. Zhi
中科院分区：
文献类型：
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作者：
Q. Jilin;Shengsong Yu;Z. Jianming;W. Zhi
永久冻土地区路堤的沉降是由几个同时发生的过程造成的，每个过程都有不同的机制。第一个是众所周知的由于下面永久冻土退化而导致的解冻沉降过程。这被认为是最有问题的，并且在之前的研究中引起了极大的关注。第二个过程是蠕变过程。现场观测表明，由于路堤的建设，多年冻土层的温度可能会显着升高，形成大面积“温暖”的冻结层，并且具有较高的蠕变倾向。同时，在新的荷载条件下，温暖季节的活动层中会发生未冻土的蠕变。第三，由于活动层中的冻融循环会改变土壤特性，因此在最初几年也会发生额外的沉降。这三个过程是交互的，这使得任何计算尝试都变得非常困难。本文首先回顾了沉降估算的基本方法及其局限性。然后结合青藏高原公路、铁路建设的实践，对可能的沉降源进行了分析。为了全面、清晰地研究整个聚落，提出了等效冻土表的概念。
Settlement of embankments in permafrost regions results from several simultaneous processes, each with a different mechanism. The first is the well-known process of thaw settlement due to the degradation of permafrost underneath. This has been considered to be the most problematic and has attracted great attention in previous studies. The second process is that of creep. Field observations show that due to the construction of embankments, the temperature in permafrost layers may rise remarkably, forming a large ‘warmer’ frozen layer with a higher tendency to creep. At the same time, creep of unfrozen soils can take place in the active layer in warm seasons under new loading conditions. Third, because freeze-thaw cycling in the active layer can change the soil properties, additional settlement would also take place in the first years. These three processes are interactive, which makes any attempts at calculation very difficult. The article first reviews the basic methodologies and their limitations for settlement estimation. Then, based on the practice in the construction of a highway and a railway on the Qinghai-Tibet Plateau, the possible settlement sources are analysed. In order to investigate the whole settlement comprehensively with clear mechanisms, the concept of an equivalent permafrost table is proposed.