高海拔地区铁路隧道施工期围岩热流密度数值模拟研究

冷负荷预测是隧道施工的重要任务,目前传统隧道冷负荷预测方法无法满足高海拔铁路隧道施工环境。为高海拔铁路隧道的冷负荷预测提供准确方法,本文建立一个热湿耦合多孔介质模型,考虑围岩孔隙率和低压环境对隧道围岩热流密度的影响。建立高海拔铁路隧道围岩热流密度预测模型。分析渗流水和衬砌的存在对围岩热流密度的影响,对比不同环境参数对围岩热流密度的影响。结果表明,隧道的冷负荷取决于围岩的热流密度。预测模型可以准确计算隧道围岩热流密度,其均方根误差（RMSE）为0.573 W/m2。围岩渗流水和衬砌对隧道热湿环境产生显著影响。压力对围岩热流密度的影响最小。围岩温度每升高10 ℃时,围岩初始热流密度增加了58.74 W/m2。此外,每当隧道目标温度增加4 ℃或孔隙率增加0.1,分别导致围岩初始热流密度减少了23.5和0.14 W/m2。本文可以为实际高海拔铁路隧道工程的冷负荷预测提供新的理论方法和参考依据。

Numerical simulation of heat flux of surrounding rock during construction of railway tunnel in high-altitude area

Cooling load prediction is an important task in tunnel construction. Traditional tunnel cooling load prediction methods cannot meet the requirements of high-altitude railway tunnel construction environments. To provide an accurate method for predicting the cooling load of high-altitude railway tunnels, this paper established a heat-moisture coupling porous medium model, which considers the influence of surrounding rock porosity and low-pressure environment on the heat flux density of tunnel surrounding rocks. A prediction model for heat flux density in the surrounding rock of high-altitude railway tunnels was established. Analyzed the impact of the presence of seepage water and lining on the surrounding rock heat flux density, and compared the impact of different environmental parameters on the surrounding rock heat flux density. The results show that the tunnel''s cooling load depends on the surrounding rock''s heat flux density. The prediction model can accurately calculate the heat flow density of the tunnel surrounding rock, with a root mean square error (RMSE) of 0.573 W/m2. Surrounding rock seepage water and lining significantly impact the tunnel''s heat and humid environment. Pressure has the smallest effect on the surrounding rock heat flux density. When the temperature of the surrounding rock increases by 10 °C, the initial heat flow density of the surrounding rock increases by 58.74 W/m2. In addition, whenever the tunnel target temperature increases by 4 °C or the porosity increases by 0.1, the initial surrounding rock heat flux density decreases by 23.5 and 0.14 W/m2, respectively. This research can provide new theoretical methods and reference bases for cooling load prediction in actual high-altitude railway tunnel projects.