透壁式通风管-块石复合气冷路基室内模型试验研究

Model test study of the cooling effect of the embankment composited with ventilated duct and crushed rock

为了研究透壁式通风管-块石复合气冷路基的降温效果,针对年均气温约-3.5℃,平均风速2.5 m·s-1,主导风向为西北方向的高原环境条件开展室内模型试验,分析了单一块石气冷路基和透壁式通风管-块石复合气冷路基的孔隙空气对流速度、特征点地温变化过程以及模型整体温度场变化过程.结果表明:在透壁式通风管的疏导作用下,透壁式通风管与块石层的复合结构能够起到强化路基体对流的效果,复合路基块石孔隙中的空气流速比单一块石路基提高约20%,由此导致复合路基模型底部的降温幅度是单一块石路基模型的2.2倍.模型整体温度场表明,复合路基能够起到储存冷量、降低下伏多年冻土地温的作用.

In order to study the cooling effect of the embankment composited with ventilated duct and crushed rock, a series of model test were carried out under the conditions similar to plateau environment, i.e. , the aver- age annual temperature of - 3.5 ℃, the average wind speed of 2.5 m· s - 1 and the dominant wind direction of northwest. The air convection velocity in crushed rock, the temperature change process at feature points and the model temperature field were obtained and analyzed. It is found that an enhanced convection effect in embank- ment can be seen within the embankment composited with ventilated duct and crushed rock. Under the cathartic effect of the ventilated duct, the air convection velocity in the composited embankment is 20% higher than that in single crushed rock embankment, and the cooling rate at the bottom of the model of the embankment is 2.2 times of the single crushed rock embankment. The model temperature field shows that the composited embankments is able to storage cold and to cool down permafrost.