季节性冻土地区高速铁路路基地温分布规律研究

TEMPERATURE DISTRIBUTION IN ROADBED OF HIGH-SPEED RAILWAY IN SEASONALLY FROZEN REGIONS

研究路基及周边地区土体地温的分布规律是季节性冻土地区高速铁路路基的稳定性分析的重要基础。结合哈大(哈尔滨——大连)高速铁路双城地区3 a的现场监测数据和气温资料,分析坡脚、天然位置及路基不同位置的地温分布规律。在此过程中,利用地温振幅、平均地温等结果,建立相应的地温估算公式,为确定数学模型的基本边界条件提供依据。建立非稳态相变温度场的数学模型,研究路基地温随时间的变化特点和沿深度的分布规律,并预测地温场的变化趋势。现场监测和模拟计算结果表明:地温分布规律主要与土体构成、土体热扩散能力、气候和位置等因素有关。季节性冻土地区高速铁路路基最终形成较为稳定的季节冻结层,相对稳定的地温和不对称的地温场。路基阴阳坡地温场的不对称,可能导致路基横向差异变形和纵向的不均匀变形,进而影响路基的稳定性。

Temperature distribution in the roadbed and neighboring soil of high-speed railway（HSR） in seasonally frozen regions has significant influence on the stability of roadbed. The temperature distributions at the toe of slope, a short distance away from the road and at different locations in the roadbed were analyzed based on the results of three years monitoring and the atmospheric temperature data at Shuangcheng district from Harbin-Dalian HSR. Formulae of temperature estimation of different locations and depths were established in terms of the temperature amplitudes and average values. A mathematical model of the unsteady phase transition of geothermal field was presented to analyze the temporal and spatial characteristics of temperatures and to predict the trends of variation of geothermal field. Monitored data and calculated results both indicated that the temperature distributions were related to the soil compositions, the thermal coefficients of diffusion, the climate and the locations, etc. The roadbed of HSR of seasonally frozen regions eventually formed a relatively stable layer of seasonal frozen with a stable temperature and asymmetric geothermal field. The difference of geothermal field of shady and sunny slopes at two sides of embankment exists and may lead to the uneven settlements transversely and longitudinally which may affect the stability of roadbed.