寒区公路路堑边坡开挖水热耦合模拟

Hydrothermal Coupling Simulation of Highway Cutting Slope Excavation in Cold Region

为研究绥大高速公路路堑边坡开挖前后的水热分布特征,利用海伦站气象数据,结合工程现场实际边坡状况,构建考虑各项气候条件的饱和/非饱和瞬态水热耦合数值计算模型,分析边坡开挖前后水分场、温度场的分布特征、冻结深度及不同工况下的差异性影响因素。结果表明:边坡开挖导致水分场大幅改变,3月中旬体积含水量大幅下降,中下旬下降幅度最大为74.61%,占整个非冻结期91.59%;随着埋深的增加,温度波动变化滞后性明显,波动范围呈指数衰减。未开挖土体冻结深度可达1.95 m,开挖边坡最大冻结深度为0.76 m,冻结消融期为31 d。不同工况下水分场分布状态不同,体积含水量高低受土体渗透性影响较大。高体积含水量会抑制冻结锋面的推进速度,延迟土体温度变化趋势,不同工况下温度变化差异性受体积含水量影响显著。

In order to study the hydrothermal distribution characteristics of the cutting slope of Suida expressway before and after excavation,a saturated/unsaturated transient hydrothermal coupling numerical calculation model considering various climatic conditions was constructed by using the meteorological data of Hailun station and the actual slope conditions of the project site,and the distribution characteristics of water field and temperature field before and after slope excavation were analyzed freezing depth and different influencing factors under different working conditions.The results show that the water field changed significantly due to slope excavation,and the volumetric water content decreased significantly in mid-March,and the maximum decrease in mid-to-late December was 74.61%,accounting for 91.59%of the entire non-freezing period.With the increase of burial depth,the temperature fluctuation change lagged significantly,and the fluctuation range was exponentially decayed.The freezing depth of the excavated soil can reach 1.95 m,the maximum freezing depth of the excavated slope is 0.76 m,and the freezing ablation period is 31 days.The distribution state of the water field is different under different working conditions,and the volumetric moisture content is greatly affected by the permeability of the soil.The high volume water content will inhibit the propulsion speed of the frozen front,delay the trend of soil temperature change,and the temperature change difference under different working conditions is significantly affected by the volumetric water content.