中文摘要：

新建哈大客运专线穿越东北中部山前平原,其中有10 km长为地下水埋深很浅的路堑段,冻胀问题突出。基于对长春西客站附近的路堑段开展的路基水热状况监测,分析路基填筑主体及其下土体水热条件时空变化过程及其对冻胀的影响,并评价运营前路基变形特性。结果表明,在现有设计和正常施工条件下,路基热稳定性良好,总体相对变形量未超过7 mm,上层冻胀变形量占据总体冻胀量的60%以上,且与地温呈负相关关系,并随着冻深而逐步减少;路基中设置的封闭复合土工膜阻隔外界水分向路基基床主体迁移,使得基床土体含水量基本稳定,从而减少分凝冰的形成;地温变化的趋势和分布特征与基床部位和表层工程措施相关:轨道板和钢筋混凝土基座增大路基的热阻,使得地温等值线在其下呈现略微"上抬"的趋势。同时正线两侧联络线使用的传统道碴层,因其降温机制使得其下的地温呈现略微"降低"的趋势。双向线路中间的排水沟下方冻结深度增大,而路基两侧的排水沟由于使用不同的工程构件,使得该部位下方及临近部位的冻结深度变化与路中排水沟下的略有不同。综合监测结果显示,监测期间试验段路基热力学稳定性良好。

英文摘要：

Harbin-Dalian passenger dedicated line crosses piedmont plain in the Northeast China,where is seasonal frozen ground region. As a 10 km cutting section of the line located in shallow groundwater area,frost heave is a serious problem in the roadbed construction. Based on monitoring results of hydrothermal conditions of the testing section near the Changchun west railway station,the hydrothermal processes in the roadbeds and their influences on the frost heave are analyzed;and the roadbed deformation before the operation of the railway is evaluated. The results indicated that,under the conditions of current design and construction,the subgrade is thermally stable,and the total deformation of the roadbed is less than 7 mm,while which of the upper layer occupied more than 60%. The frost heave value is negatively correlated with the ground temperature and reduces gradually with the frozen depth. The geomembrane barrier laid in the subgrade prevents the external moisture migrating into the roadbed,resulting in the relatively stable water content of the roadbed soils,thereby reducing the formation of segregation ice. The time-space distribution feature of the ground temperature is related to roadbed position and the surface structure. The ground temperature contour shows a slight elevation trend under the track panels and reinforced concrete base,as they increases the thermal resistance of the roadbed. The ground temperature slightly decreases under the traditional ballast layers of the contact lines along the two sides of the main line,caused by the cooling mechanism of the ballast layer. The frozen depth under the middle gutter is higher than that under the gutters at the two sides,due to the different engineering components used in construction of the gutters. The summarized results show that the testing roadbed has good performance of thermo-dynamic stability during monitoring period.