岛状多年冻土区高速铁路路基热状态及工程措施效果分析

Thermal State and Effect Analysis of Engineering Measures of High-speed Railway Subgrade in Island Permafrost Region

为揭示岛状多年冻土区高速铁路路基热状态,提出合理有效的制冷结构,在新建哈尔滨至伊春高速铁路某车站试验段开展现场监测,获得岛状多年冻土的地温数据;基于实测地温数据,采用冻土水热耦合理论,对将在试验段实施的两侧双排普通热棒路基、两侧双排+中心单排全季热棒路基、两侧单排+基底横向通铺全季热棒路基3种制冷路基结构进行数值模拟,对比了3种制冷路基结构的地温分布特征及对下伏岛状多年冻土的降温效果。研究结果表明:铁力地区年均气温和降水呈增大趋势,天然场地岛状多年冻土地温在-0.3℃左右,属于高温极不稳定多年冻土。3种制冷路基结构中,两侧单排+基底横向通铺全季热棒对岛状多年冻土保护及降温效果最优,两侧双排普通热棒最差。普通热棒路基的多年冻土上限呈“两侧凸,中间凹”形态,抬升不明显;全季热棒路基的多年冻土上限呈“上凸缓斜平顶”形态,抬升显著。研究成果可对多年冻土区高速铁路路基建设和结构优化提供技术支撑。

To reveal the thermal state of the high-speed railway(HSR)subgrade in the island permafrost region and propose effective cooling structures,field monitoring was conducted in the experimental section of a station on the newly constructed Harbin to Yichun HSR to obtain ground temperature data of island permafrost.Subsequently,based on the measured ground temperature data,numerical simulations were performed using hydro-thermal coupling theory to compare the temperature distribution characteristics and cooling effects on the underlying island permafrost of three cooling subgrade structures to be implemented at the station.The three structures include ordinary heat pipes subgrade(OHPS)with double rows of heat pipes on both sides,all-season heat pipes subgrade formed by OHPS plus a single row of heat pipes in the center,and all-season heat pipes subgrade formed by OHPS plus a horizontal arrangement of heat pipes at the base.The results show that the average annual temperature and precipitation in the Tieli Region are on the rise,with the ground temperature of the natural site’s island permafrost at around-0.3℃,which is high-temperature and extremely unstable permafrost.Among the three cooling subgrade structures,the all-season heat pipes subgrade provides the best protection and cooling effect on the island permafrost,while the ordinary heat pipes subgrade performs the worst.The upper limit of permafrost under the ordinary heat pipes subgrade shows a“convex on both sides,concave in the middle”pattern with insignificant uplift,while the upper limit of permafrost under the all-season heat pipes subgrade exhibits an“upward convex gentle slope with a flat top”pattern with significant uplift.The research findings will provide technical support for the construction and structural optimization of HSR subgrade in permafrost regions.