青藏铁路多年冻土区超过上临界高度路堤的分布及特征

为明确路堤高度对青藏铁路多年冻土区稳定性的影响,通过对沿线多年冻土区中融区路堤冻结深度和冻土区路堤监测断面实测地温监测数据的分析,研究青藏铁路多年冻土区路堤的地温特征和变化规律。结果表明:青藏铁路多年冻土区沿线路堤的临界高度是不一致的,在多年冻土区腹地的越岭地段,其年平均气温和地温均较低,冻土环境相似,路堤的上临界高度为7 m左右,在地势相对较低、气温和地温相对较高的其他地貌单元中,路堤临界高度则相对较低;青藏铁路多年冻土区高于上临界高度的路堤主要分布在昆仑山、风火山、唐古拉山等山区地貌单元中。

Distribution and Characteristics of Embankment over Upper Critical Height in Permafrost Region of Qinghai-Tibet Railway

In order to clarify the influence of embankment height on the stability of permafrost region of Qinghai-Tibet Railway,the geothermal characteristics and variation laws of embankment in permafrost region of Qinghai-Tibet Railway were studied by analyzing the freezing depth of embankment in thawing region and the measured geothermal data of the embankment monitoring section in permafrost region.Results show that the critical heights of embankments along the Qinghai-Tibet Railway in permafrost regions are different.In the ridge-crossing area in the hinterland of permafrost region,the annual average temperature and ground temperature are lower,and the frozen soil environments are similar.The upper critical height of embankment is about 7 m.In other geomorphic units with relatively low terrain,relatively high temperature and ground temperature,the critical height of embankment is relatively low.The embankments above the upper critical height in permafrost region of Qinghai-Tibet Railway are mainly distributed in the geomorphic units of Kunlun Mountains,Fenghuo Mountain and Tanggula Mountains.