峡谷风对寒区隧道抗冻设防长度的影响

Study on the influence of canyon wind on frost resistance length of tunnel in cold regions

峡谷风作为高山峡谷区、高原山区的特定产物,是影响高寒山区隧道抗冻设防长度的关键因素,开展峡谷风作用下的寒区隧道抗冻设防长度研究对寒区隧道病害提前预防和有效治理具有重要的研究价值与指导意义。本文采用现场实测、数值模拟、因子设计等综合研究方法,围绕峡谷倾角、峡谷风下风向与隧道洞轴线夹角、隧道洞口相对高度三种控制指标,开展寒区隧道抗冻设防长度变化规律研究以及相应机理分析。首先,依托国家重点隧道工程开展现场监测工作,以0℃作为隧道冻害发生的临界温度,得出隧道的实测抗冻设防长度为200~300 m;其次,基于高山峡谷区实际隧道工况的各项控制指标,建立峡谷风下寒区隧道抗冻设防长度的数值模型并开展数值模拟试验,得出数值模拟的结果为237.78 m,与隧道实测抗冻设防长度高度吻合;最后,通过对数值试验结果进行分析得出,峡谷风作用下寒区隧道抗冻设防长度受多因素耦合影响,其中峡谷倾角对隧道抗冻设防长度的影响最大,峡谷风下风向与隧道洞轴线夹角及隧道相对高度交互作用影响最小,继而深入探究峡谷风条件对隧道抗冻设防长度的影响机理。本研究对峡谷风条件下的寒区隧道抗冻设防长度计算具有重要参考价值。

As a specific product of alpine canyon area and plateau mountain area,canyon wind is the key factor affecting the frost resistance length of tunnel in alpine mountain area.Therefore,it is of great research value and guiding significance to study the frost resistance length of tunnel in cold regions under the action of canyon wind for the early prevention and effective treatment of tunnel diseases in cold regions.In this paper,the comprehen⁃sive research methods such as field measurement,numerical simulation and factor design are used to carry out the research on the variation law of frost resistance length of tunnel in cold regions and the corresponding mecha⁃nism analysis around the three control indexes of canyon inclination,the angle between the downwind direction of canyon wind and the axis of tunnel and the relative height of tunnel entrance.Firstly,this paper relies on the national key tunnel project to carry out on-site monitoring work.Taking 0℃as the critical temperature of tunnel frost damage,it is concluded that the measured frost-resistant fortification length of the tunnel is 200~300 m;Secondly,based on the control indexes of the actual tunnel conditions in the alpine canyon area,the numerical model of the frost resistance length of the tunnel in cold regions under the canyon wind is established and the nu⁃merical simulation test is carried out.The numerical simulation result is 237.78 m,which is highly consistent with the measured frost resistance length of the tunnel.Finally,through the analysis of the numerical experiment results,it can be concluded that the frost resistance length of the tunnel in cold regions under the action of the canyon wind is affected by the coupling of multiple factors,among which the canyon inclination angle has the greatest influence on the frost resistance length of the tunnel.The interaction between the angle between the downwind direction of the canyon wind and the axis of the tunnel and the relative height of the tunnel has the least influence,and the influence mechanism of the frost resistance length of the tunnel under the condition of the canyon wind is deeply explored.This study has important significance and reference value for the calculation of frost-resistant fortification length of tunnels in cold regions under canyon wind conditions.