Abstract
This paper discusses the deformation mechanism of a utility tunnel crossing active ground fissures in Xi’an as observed in a physical model test. The purpose of this work is to confirm the precise effects of ground fissures on utility tunnels. The physical simulation experiment is carried out to measure the earth pressure and the strain relationship of the structure and the structural displacement. The structure appears to have been destroyed by torsion. The structural deformation located in the tunnel’s footwall was more serious than that in the hanging wall. However, at the top of the utility tunnel structure, the earth pressure in the footwall was less than that in the hanging wall. The increased range of the hanging wall at 0.3–1.5 m (the prototype within the range of 22.5 m) and decreased range of the footwall at 0.3–0.8 m (the prototype within the range of 12 m) were basically consistent with changes in the contact pressure at the structure’s bottom. This was roughly consistent with the main deformation zone of ground fissures mentioned in the specification, with the hanging wall at 0–20 m and footwall at 0–12 mm. Displacement meter data shows that the structure tends to deform to the lower right as the utility tunnel is “twisted” clockwise. These observations mark a notable departure from the previously published failure mode of metro tunnels under active ground fissures.
Highlights
Simultaneously. e tensile displacement of ground fissures in Xi’an is generally under 10 m and the fissures are nearly closed, while the buried depth of utility tunnels in the area is generally less than 10 m
Research data speculates that the Xi’an ground fissure f6 develops on the east side of the construction site. is study intended to carry out a physical model test on the deformation and failure mode of the utility tunnel with a 45° oblique penetration of the ground fissure. e model test was designed with a geometrical scale
A model test was performed in this study to assess the mechanical behavior of a utility tunnel crossing a ground fissure. e earth pressure, stress–strain relationship of the structure, and the structural displacement at various locations in the model structure were measured. e conclusions can be summarized as follows
Summary
E rows of 45° strain flowers were arranged at the top, bottom, and sides of the model with nine flowers in each row to measure strain in different directions of the utility tunnel lining. A total of eight measuring lines were arranged along the axial direction of the structure—three at the top and five at the bottom—to test the changes in longitudinal earth pressure during the experiment. Each measuring line was equipped with seven earth pressure boxes to test the changes in earth pressure at the sides of the structure (Figure 8). At the intersection of the structure and the ground fissure, which is 0.08 m on each side, a total of three measuring sections and 24 displacement meters are used to measure the differential settlement of the utility tunnel structure (Figure 9)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
