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为研究东北大兴安岭多年冻土地区路基工后沉降变形特点,选取中俄(中国-俄罗斯)原油管道漠大(漠河—大庆)线林区伴行路典型断面,沉降监测设备采用分层沉降仪,通过沉降管上磁力环位置的变动来跟踪观测路基沉降变化,以DS18B20温度传感器为温度采集单元,布设温度监测系统监测多年冻土由于筑路引起的地温变化,并结合室内试验对多年冻土地温和冻土上限变化及路基沉降变形进行试验研究。研究结果表明:工程竣工通车后的2年里,由于路基填土覆盖致使地温升高、冻土产生退化、冻土上限下移;季节活动层压缩和冻土融化压缩是引起多年冻土区路基沉降的主要变形源,冻土融化压缩产生的变形所占比例最大,占总沉降量的50%;每年8~11月份时段融化层压缩导致路基沉降变形明显,进入12月份随着季节融化层冻结和冻土上限上移稳定,路基沉降开始趋缓;路基融沉发育具有一定的坡向性,在一个冻融循环期内,阴坡面路基下多年冻土融化时间比阳坡面的少30d左右,阳坡面路基沉降量大于阴坡面路基沉降量;在相同条件下,高含冰量冻土融化压缩变形大于低含冰量冻土融化压缩变形,填高大于3m的路堤随着填土高度的增加,冻土融化压缩变形增大。研究结果可为大兴安岭多年冻土地区修建公路和路基沉降变形病害分析提供理论参考。
In order to study the characteristics of post-construction settlement of subgrade in the permafrost region in the Daxinganling area, a typical cross-section of the associated road in the Muda (Mohe-Daqing) line of crude oil pipeline in China-Russia (China-Russia) was selected. DS18B20 temperature sensor was used as the temperature acquisition unit and a temperature monitoring system was set up to monitor the change of ground temperature caused by road construction in permafrost. Combined with indoor test, the temperature and temperature of permafrost Soil upper limit changes and subsidence deformation test. The results show that: in the two years after the project is completed and opened to traffic, the ground temperature increases, the permafrost becomes degenerated and the upper limit of the permafrost goes down. The seasonal active layer compression and frozen soil thawing and compression are the main causes of the permafrost region The main deformation source of subgrade settlement is the largest proportion of deformation due to thawing and compression of frozen soil, accounting for 50% of the total sedimentation volume. During the period from August to November each year, the melting layer compression leads to obvious deformation and settlement of roadbed. As the season melts The upper limit of freezing and permafrost up-shift stability, subsidence of subgrade began to slow down; subgrade melt-sink development has a certain aspect, in a freeze-thaw cycle, permafrost thawing time under the subgrade of the shady slope is less than the sunny Under the same conditions, the thawing and compressive deformation of the frozen ice with high ice content is larger than the melting and compressive deformation of the frozen soil with low ice content. When the embankment filled with more than 3m of embankment filled with soil Increased height, frozen soil compression deformation increases. The results provide a theoretical reference for the analysis of the deformation and deformation of road and embankment settlement in the permafrost area of Daxinganling.