多年冻土拓宽路基差异沉降特征分析  

Characteristics Analysis of Differential Settlement of Widening Embankment in Permafrost Regions

作　　者：袁堃[1] 汪双杰[1] 牛富俊[2,3] 陈建兵[1] 李金平[1] 

机构地区：[1]中交第一公路勘察设计研究院有限公司高寒高海拔地区道路工程安全与健康国家重点实验室,陕西西安710065 [2]中国科学院西北生态环境资源研究所冻土工程国家重点实验室,甘肃兰州730000 [3]中国科学院大学,北京100049

出　　处：《中国公路学报》2016年第9期21-28,共8页China Journal of Highway and Transport

基　　金："十二五"国家科技支撑计划项目(2014BAG05B07;2014BAG05B03)

摘　　要：为了分析多年冻土拓宽路基差异沉降变形特征及形成机理,在青藏公路楚玛尔河地区开展了冻土拓宽路基试验研究,分析了路基拓宽后冻土地温、冻土上限、路基变形、新旧路基差异沉降变化特征以及拓宽路基对旧路的附加影响。结果表明：冻土路基拓宽后改变了坡角处原有的水热交换条件,造成新建拓宽路基下部多年冻土出现迅速升温退化;现场路况调查以及分层沉降监测显示新建拓宽路基在运营后发生大幅沉降变形,沉降主要集中在新旧路基结合处,变形主要来自于地表下2~3m处土层的压缩固结,该层土处于原天然地表下冻土上限附近,表明冻土融化下沉是导致拓宽路基发生沉降的主要原因;新旧路基间差异沉降量达到6cm,造成路基横坡改变率达到0.8%,超过《公路路基设计规范》（JTGD30—2015）中横坡改变率0.5%的上限要求;路基拓宽后使得黑色路面宽度增加,进而导致吸热量增加,加之拓宽路基产生的附加荷载,导致旧路中心处沉降在路基拓宽后初期内迅速发展。In order to analyze the deformation characteristics and formation mechanism of differential settlement of widening embankment in permafrost regions,experimental research on permafrost widening embankment along Qinghai-Tibet Highway（Chumaer River area）was conducted,and permafrost ground temperature,permafrost table,embankment deformation,differential settlement changing characteristics of new and old embankment and additional influence imposed by widening embankment on old embankment were analyzed.The results show that widening embankment has a large influence on the thermal regime in side-slope of old embankment,which typically results in rapid warming and degeneration of permafrost beneath the newly-built widening embankment;field road condition survey and layered settlementmonitoring show that large settlement and deformation occur in widening embankment in operational period,of which the occurrence of settlement typically concentrates on the juncture between old and new embankment and deformation is mainly resulted from soil consolidation at depth of 2to 3munder the ground surface.This layer corresponds to permafrost table under the natural ground surface,which indicates the settlement of widening embankment in permafrost regions mainly results from permafrost thaw consolidation;the differential settlement between new and old embankment reaches as high as 6 cm,resulting in change rate of transverse embankment reaching up to 0.8%,which is higher than limit requirement of 0.5% in specifications for design of highway subgrades.Furthermore,width of black pavement is increased after the widening of embankment,which results in the increase of heat absorption of embankment.Meanwhile the additional load resulting from widening embankment leads to rapid settlement development in middle of old embankment at the beginning after the completion of widening embankment construction.

关 键 词：道路工程 多年冻土 试验路监测 差异沉降 拓宽路基 

分 类 号：U416.16[交通运输工程—道路与铁道工程]