使用图像分析研究隧道衬砌管片的位移变化

以复合材料加固前后的盾构隧道管片为对象,进行了盾构隧道管片在侧向荷载作用下变形能力和极限承载力的整环加载试验,使用图像处理技术对加固前后衬砌圆环管片接缝两侧的位移变化进行了研究。根据加载过程中不同时刻的试验图像,使用粒子图像测速技术得到了不同时刻、不同位置接缝两侧混凝土管片的位移变化情况。结果表明:未加固阶段管片顶部接缝处管片表面位移相对较小,两侧位移变化不相等,封顶块位移大于邻接块位移,加载结束时最大位移发生在封顶块位置;整环加固后,封顶块位移大于邻接块位移,加载结束时裂缝开始扩展;加固前后位移变化幅度大小次序依次是封顶块、标准块、邻接块和底块,破坏最先发生位置是封顶块和邻接块的连接位置;使用复合材料加固后,各处接缝两侧管片位移变化幅度及整体位移变化量均小于加固前,管片承载力增加,强度明显提高。本文结果对研究隧道衬砌破坏机理有一定的参考价值。

Displacement Features of Tunnel Lining Segments Using Image Processing Techniques

Taking the shield tunnel segments as a research object,a lining structure experiment was conducted to investigate the deformability and ultimate bearing capacity of the segments subjected to lateral forces before and after reinforced by composite materials.The displacement variations of joints between various segments were investigated by image processing techniques according to the images photographed during the experiment.The particle image velocimetry technique was used to compute the displacement variations of the joints in the concrete tunnel segment at different time and different locations.It shows that before the lining structure was reinforced,the changes of displacements of the joints were relatively small and the displacement variations at both sides were not same,and the position of maximum displacement was the top segment as the loading finished;after the lining structure was reinforced,the displacements at the top segment was also larger than those of the side one,and the cracks propagated as the loading process finished;the variations in magnitude of displacement were the largest,medium,and smallest,respectively at the top,standard,side and bottom segments before and after the lining structure reinforcement;failure occur initially in the connection between the top and side segment;after the lining structure was reinforced,the changes in magnitude and variations of displacement of the joints were smaller than those before the shield tunnel was reinforced;reinforcement with composite materials efficiently enlarged the strength of the segment.The results obtained in the current study may be referable in investigating the failure mechanism of lining structure of tunnel.