地下车站侧墙混凝土结构抗裂技术研究与应用
郦亮1王全超2,3程璐2,3占文2,3
Research and Application of Crack-resistance Technology for Underground Station Side-wall Concrete Structure
LI Liang1WANG Quanchao2,3CHENG Lu2,3ZHAN Wen2,3
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作者信息:1.宁波市轨道交通集团有限公司， 315101， 宁波
2.中交武汉港湾工程设计研究院有限公司， 430040， 武汉
3.海工结构新材料及维护加固技术湖北省重点实验室， 430040， 武汉
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Affiliation:1.Ningbo Rail Transit Group Co., Ltd., 315101, Ningbo, China
2.CCCC Wuhan Harbour Engineering Design and Research Co., Ltd., 430040, Wuhan, China
3.Hubei Key Laboratory of Advanced Materials and Reinforcement Technology Research for Marine Environment Structures, 430040, Wuhan, China
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关键词:
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Key words:
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DOI:10.16037/j.1007-869x.2024.01.026
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中图分类号/CLCN:TU755.9∶U231.4
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栏目/Col:研究报告
摘要:
［目的］城市轨道交通工程地下车站侧墙混凝土开裂，会威胁地铁车站结构安全，需分析其开裂的原因，并提出地下车站侧墙混凝土控裂的关键技术。［方法］通过降低水泥用量及掺加高效抗裂剂，制备了低水化速率、微膨胀混凝土；对比研究了组分优化前后的混凝土对结构力学性能、绝热温升及体积变形的影响，从而验证地下车站侧墙混凝土组分改善后抗裂性能提高；在此基础上，对地下车站混凝土侧墙结构进行有限元模型仿真分析，计算不同侧墙厚度、分段长度对抗裂安全系数的影响，从而在满足抗裂安全系数前提下，确定不同季节地下车站混凝土侧墙分段浇筑的最佳长度；最后通过监测地下车站试验段各典型分段的温度变化规律，提出了侧墙混凝土温度控制指标。［结果及结论］地下车站侧墙混凝土收缩及侧墙混凝土受约束是引起地下车站混凝土侧墙开裂的主要原因。关键控裂措施为：引入高效抗裂剂提高混凝土抗裂性能，优化不同季节地下车站混凝土侧墙分段浇筑长度降低混凝土约束，严格控制混凝土温度指标。采用上述关键控裂措施后，地下车站侧墙混凝土裂缝数量极大减少。
Abstracts:
［Objective］ Cracking in the concrete of urban rail transit project underground station side-walls can pose a threat to the structural safety of metro stations. It is essential to analyze the causes of cracking in the concrete of USSW (underground station side-walls) and propose key technologies for controlling it. ［Method］ Low hydration rate and slightly expansive concrete is prepared by reducing cement usage and adding highly effective anti-cracking agents. Its impacts on structural mechanical properties, thermal insulation temperature rise, and volume deformation are compared before and after the composition optimization, which verifies the improvement of USSW concrete composition crack-resistance performance after optimization. Based on this, a finite element model simulation analysis is carried out on USSW concrete structures, and the influence of different wall thicknesses and segment lengths on crack-resistance safety factor is calculated. Thus, under the premises of satisfying crack-resistance safety factor, the optimal lengths of USSW segmented concrete-pouring for different seasons are determined. Finally, the temperature change law of typical segments in the experimental section of the underground station is monitored to propose temperature control indicators for side-wall concrete. ［Result & Conclusion］ The contraction of USSW concrete and the constraints on it are the main causes of cracking in USSW concrete. Key crack control measures include introducing highly effective anti-cracking agents to enhance concrete crack-resistance performance, optimizing the USSW segmented concrete-pouring lengths for different seasons to reduce concrete constraints, and strictly controlling concrete temperature indicators. Implementing these key crack control measures significantly reduce the number of cracks in the concrete of USSW.
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