Research and Application of Crack-resistance Technology for Underground Station Side-wall Concrete Structure
Journal Title: Urban Mass Transit - Year 2024, Vol 27, Issue 1
Abstract
[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.
Authors and Affiliations
Liang LI, Quanchao WANG, Lu CHENG, Wen ZHAN
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