高寒地区铁路隧道复杂衬砌结构最优浇筑长度数值分析研究

摘要

In this paper,a railway tunnel entrance in alpine region is the obj ect of study.A finite ele-ment software of Midas/GTS is used to simulate the whole process.It is based on the Mohr-Cou-lomb ideal elastic-plastic model and the linear elastic model.The effect of extreme temperature load on the lining structure of railway tunnel is analyzed,and the optimal permitted pouring length of lining structure is also obtained by related research.When the difference in temperature is 60 ℃(-30 ℃~30 ℃),through the numerical analysis on different pouring length of lining structure,it is concluded that:(1 )Difference in pouring length of lining structure has little effect on the dis-placement along the depth of the tunnel direction;The displacement of different part of the lining structure increases with the raise of the section length of railway tunnel.(2)Thanks to the impor-tant interaction of insulating layer,the effect on the lining of railway tunnel is obviously decreased during the temperature changes.(3)Difference in pouring length of lining structure has significant effect on the stress distribution:The stress distribution of different part of the lining structure in-creases with the raise of the section length of railway tunnel.(4)Through the numerical calcula-tion,it is concluded that the optimal section length of lining structure is 6m under the conditions of extreme temperature load for this proj ect.%以某高寒地区铁路隧道进口段作为研究对象，利用 Midas／GTS 有限元软件基于Morh-Coulomb的理想弹塑性模型和线弹性模型对铁路隧道衬砌进行数值模拟，明确极端温度荷载作用对隧道各层衬砌的影响，并探究出本铁路隧道衬砌的最优浇筑分段尺寸．通过对在-30℃～30℃，温度差为60℃温度荷载作用下的不同分段长度隧道衬砌数值分析，得出：（1）不同分段长度的隧道衬砌沿纵深方向位移变化不大；不同部位的衬砌位移变化呈现出随着隧道衬砌分段长度增大而变大的规律．（2）由于隔热层在温度变化中起到巨大的作用，明显降低了环境温度对隧道衬砌变形的影响．（3）隧道衬砌分段长度变化对应力大小分布有显著影响：不同部位的衬砌应力大小分布呈现出随着隧道衬砌分段长度增大而变大的规律．（4）通过数值模拟计算得出针对本工程在极端温度荷载作用下最优衬砌分段长度为6 m．