摘要
基于2006-2012年青藏铁路多年冻土区唐古拉山南侧安多断面地温监测资料,分析了多年冻土南界附近路基下多年冻土的退化过程及其影响因素.结果表明:该监测断面天然场地多年冻土退化表现为多年冻土天然上限下降与多年冻土地温升高,观测期内多年冻土天然上限下降0.29 m,下降速率为4 cm·a-1;路基下10 m处多年冻土温度升高0.03℃,升温速率为0.004℃·a-1.该监测断面路基左路肩下多年冻土退化表现为多年冻土人为上限下降、多年冻土地温升高、多年冻土下限抬升以及多年冻土厚度减少.观测期内多年冻土人为上限下降0.41 m,下降速率为6 cm·a-1;路基下10 m处多年冻土地温升高0.06℃,升温速率为0.009℃·a-1;多年冻土下限抬升0.50 m,抬升速率为7 cm·a-1;多年冻土厚度减少0.90 m,减少速率为13 cm·a-1.工程作用是导致路基下多年冻土退化的主要原因,气温升温与局地因素中的冻结层上水发育促进了这一退化过程.路基下融化夹层的出现,导致多年冻土垂向上由衔接型变为不衔接型.
Based on the ground temperature monitored in the Qinghai-Tibet Railway near the southern limit of permafrost during 2006 - 2012, the degradation of permafrost and its influence factors were analyzed. The results show that whether in the original permafrost or in the permafrost under an embankment, the permafrost table was declining and the ground temperature was rising. In the monitoring period, the permafrost table had declined 0.29 m, with a rate of 4 cm·a-1 ; the ground temperature had risen 0.03℃ at the depth of 10 m, with a rate of 0. 004℃·a-1. The depth of artificial permafrost table under an embankment was larger than that under origi- nal permafrost; the ground temperature under an embankment rising at the depth of 10 m was higher than that under the original surface. It is an obvious feature that the permafrost base under the embankment was lowering, but the permafrost thickness was thinning. It is concluded that engineering effect is the major cause resulting in the permafrost degradation under the embankment in this region, and other factors, such as air temperature rising, suprapermafrost water development, etc. , are also accelerating the degradation. The thawing interlayer formed under the embankment will change the connected frozen ground into detached one, which is an unavoida- ble stage in the degradation process of permafrost.
出处
《冰川冻土》
CSCD
北大核心
2014年第4期767-771,共5页
Journal of Glaciology and Geocryology
基金
国家重点基础研究发展计划(973计划)项目(2012CB026106)
国家自然科学基金重点项目(41030741)
冻土工程国家重点实验室自主课题(SKLFSE-ZT-09)资助
关键词
青藏铁路
路基
多年冻土
冻土退化
Qinghai-Tibet Railway
embankment
permafrost
degradation of permafrost
作者简介
孙志忠（1974-），男，辽宁清原人，副研究员，2006年在中国科学院寒区旱区环境与工程研究所获博士学位，现主要从事冻土工程与环境方面的研究．E—mail：sun@lzb．ac．cn
