退化性多年冻土地区公路路基地温和变形规律

 青藏高原多年冻土地区公路路基地温、变形监测资料表明，在工程活动和气候变暖双重作用下，路基下多年冻土普遍存在着上限下降和地温升高等特征退化，从而产生了以融沉为主的公路路基病害。基于青藏公路唐南段和青康公路K369段路基地温和变形的现场监测资料，总结退化性多年冻土地区路基的两类典型变形——横向不均匀变形和横向均匀变形规律，并分析路基地温、变形特征及其相互关系。结果表明，多年冻土地区路基的稳定性，最终取决于路基下伏冻土的地温变化和含冰量状况，其温度状况和路基路面的变形紧密相关。对于横向不均匀变形路基，多年冻土地区路基温度场的不对称性导致路基下多年冻土人为上限在路基下差异巨大，土层冻融状态的不对称最终引发路面变形在横向上的差异。退化性多年冻土区横向变形不均匀路基全年以沉降变形为主，且左、右沉降量差异较大，易于诱发纵向裂缝病害。对于横向变形均匀路基，退化性多年冻土地区公路路基变形以下沉变形为主，绝大部分路段没有明显的冻胀变形过程或冻胀变形很小，基本表现为年际的均匀沉降变形。横向变形均匀路基横向上变形比较均匀，年变形量相差不大，路基变形对路基稳定性和路面的影响较小。由于沿路基走向工程地质条件的差异，可能会形成局部沉降或波浪沉降变形病害。

GROUND TEMPERATURE AND DEFORMATION LAWS OF HIGHWAY EMBANKMENTS IN DEGENERATIVE PERMAFROST REGIONS

The observation data of ground temperature and embankment deformation in the permafrost regions on the Qinghai—Tibet Plateau show that most of artificial permafrost tables under the embankment decline gradually and the ground temperatures of permafrost under the embankment rise universally due to the effects of global warming and human activities. Thus，most of highway diseases induced by thaw settlement come into being. Based on the observation data of ground temperature and embankment deformation at Tangnan of Qinghai—Tibet highway and those at section K369 of Qingkang highway，the rules of transverse uneven and even deformations of embankments are summarized. The ground temperature and embankment deformation characters are analyzed；and the relationship and interaction between ground temperature and embankment deformation are presented. The observation results show that the embankment stability in the permafrost regions depends on the changes of ground temperature and ice content of permafrost under embankment，and the ground temperature status closely relates with the embankment deformation. As for the transverse uneven deformation embankment，the asymmetrical thermal regime results in the enormous difference of the artificial permafrost tables under north and south slopes；and the asymmetrical frozen and thawing state of embankment soil result in the transverse uneven deformation of the embankment eventually. The transverse uneven deformation embankment in degenerative permafrost regions results in great differential deformation between left and right embankment shoulders，which induces the longitudinal cracking disease. As for the transverse even deformation embankment in degenerative permafrost regions，there are little differential deformations between left and right embankment shoulders，thus the embankment deformation has few effects on the stability of embankment and pavement. Due to the engineering geological differences along highway，the undee deformation or local settlement will come into being in the transverse even deformation embankment.