The working shaft sidewall of shield tunnel constructed by cut and cover method is located in a sealed space composed of maintenance structure,ring beam,bottom floor and formwork.which is subject to a strongly constraint and difficult to construct,thus the leakage can be always observed due to the shrinkage cracking and non-compact pouring of concrete.Based on the Jiangyin Jingjiang Yangtze River Tunnel,the compactness of concrete structure with different concrete materials and construction techniques were compared through laboratory test and a series of field model tests.The results of model test and engineering application showed that the use of self-compacting and high-crack resistant concrete,combined with the control of distribution process,pouring rate,layered pouring standing time,and supplemented by necessary vibration,can ensure the compaction of concrete,and further combined with anti-crack temperature control measures,can eliminate concrete shrinkage cracks,then avoid leakage of the working well sidewall.
维普
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