Tunnel lining concrete is a typical example of thin-walled,large-volume concrete.During construction,the high hydration temperature of pumped concrete and the significant constraints imposed by the surrounding rock often lead to temperature-induced cracking.To explore reasonable temperature control measures,we employed three-dimensional finite element software to analyze the temperature field and thermal stress distribution in a typical tunnel lining section of the Central Yunnan Water Diversion Project.Contact elements were used to model the inter-actions between the surrounding rock and the lining.Based on on-site monitoring data,we performed a feedback a-nalysis on the surface insulation coefficient of the lining section,which was 16.7 kJ/(m2·h·℃).We investiga-ted how different pouring temperatures,section lengths,seasons,and the autogenous volumetric deformation of con-crete affect the thermal stress field of the concrete lining.Our findings indicate that higher pouring temperatures in-crease thermal stress;specifically,a 4℃ rise in pouring temperature reduces the minimum anti-cracking safety fac-tor by 0.30.The maximum stress exceeded 3.5 MPa when concrete was poured during high-temperature seasons.Appropriate segment lengths for the lining structure and micro-expansion concrete can enhance crack resistance.The findings offer valuable insights for temperature control in tunnel lining concrete for the Central Yunnan Water Diversion Project.
关键词
隧洞衬砌/三维有限元/温度应力场/温控措施/抗裂风险/滇中引水工程
Key words
tunnel lining/3D finite element analysis/temperature stress field/temperature control measures/cracking risk/Central Yunnan Water Diversion Project
维普
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