In view of the key problems such as the repeated action of high pressure inside and outside the deep tunnel of single-layer lining, and the coupling effect of tunnel structure and soil under ultra-deep soil, the design safety of the segment structure was verified by combining a variety of working conditions, and the construction and formation adaptability of the segment structure and the ultimate failure characteristics of the segment structure were studied, and the repeated loading cycle test of storage and drainage was emphatically increased.

The hydraulic system of the segment loading test adopts a combination of tension and compression loading mode with 45 loading points, which realizes the axisymmetric distribution of the load distribution consistent with the design model, and 15 loading points are adopted to simulate the shield thrust and inter-ring prestress in the longitudinal direction of the tunnel. A total of 1,040 measuring elements are buried in the monitoring hydraulic system, and the displacement and deformation of the segment structure are comprehensively monitored by a three-dimensional laser scanner, meanwhile the amount of data obtained is tens of thousands of times that of the traditional displacement meter. Non-contact testing methods such as binocular DIC digital photography technology are used to monitor crack development in real time. By the first time on this product, our engineering team developed an adaptive formation resistance loading system, considering the fact that the effect of formation resistance on tunnels with internal pressure is much higher than that of ordinary tunnel linings, which can realize the verification of formation structure models with different resistance coefficients.