高纬度多年冻土区路基工后沉降变形

发布时间：2018-08-17 17:36

【摘要】：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。
[Abstract]:In order to study the settlement and deformation characteristics of roadbed in permafrost region of Daxing'anling in Northeast China, the typical section of accompanying road in forest area of Sino-Russian crude oil pipeline (Mohe-Daqing) is selected, and the settlement monitoring equipment adopts stratified settler. Through the change of magnetic ring position on the settlement pipe to track and observe the subgrade settlement change, the DS18B20 temperature sensor is used as the temperature acquisition unit, and the temperature monitoring system is set up to monitor the ground temperature change caused by the road construction in permafrost. The upper limit of frozen soil and the settlement of roadbed are studied by laboratory test. The results show that in the two years after the completion of the project, the soil temperature is raised and the frozen soil is degraded, and the upper limit of the frozen soil is moved down because of the subgrade fill cover. Seasonal active layer compression and permafrost thawing compression are the main deformation sources of roadbed settlement in permafrost regions, and the proportion of deformation caused by permafrost thawing compression is the largest. It accounts for 50% of the total settlement, the subgrade settlement is obviously caused by the thawing layer compression in August and November each year. In December, with the freezing of the thawed layer and the upper limit of frozen soil moving up and stabilizing, the subgrade settlement begins to slow down. The thawing development of subgrade has a certain aspect of slope. In a freeze-thaw cycle period, the thawing time of permafrost under the overcast slope is about 30 days less than that of the sunny slope, and the settlement of the subgrade on the sunny slope is larger than that on the shady slope, and under the same conditions, The thawing compression deformation of frozen soil with high ice content is larger than that of low ice content frozen soil, and the embankment with filling height more than 3m increases the thawing compression deformation of frozen soil with the increase of filling height. The results can provide a theoretical reference for the analysis of highway and subgrade settlement and deformation in permafrost region of Daxing'anling Mountains.
【作者单位】：东北林业大学土木工程学院;
【基金】：黑龙江省水利科技项目(SGZL/KY-01) 大庆油田有限责任公司重点科研项目(2013022411)
【分类号】：U416.168

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