Test and field application of fracture evolution of large-span tunnel under NPR bolt compensation support system

IF 8.2 1区工程技术 Q1 ENGINEERING, CIVIL

Underground Space Pub Date : 2025-02-15 DOI:10.1016/j.undsp.2024.12.002

Jun Yang , Kexue Wang , Wenhui Bian , Yanbo Zhang , Xiaohui He , Yi Fang , Zhicheng Sun

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引用次数: 0

Abstract

Shallow-buried large-span tunnels may bend or collapse owing to loads, and their surface structures present considerable safety issues. At Huashanyilu station on Qingdao Metro Line 6 in China, theoretical studies and interior model tests were conducted to effectively increase the bearing capacity of the tunnel. The anchoring bearing mechanism of the high prestress compensating support system was revealed, and the system was built using a negative Poisson’s ratio (NPR) bolt at its core. We compared and analyzed the fracture evolution characteristics of the compensating and conventional support systems under various loads. The results showed that the compensating support system effectively increased the support strength and residual safety factor of the bearing arch, whereas the use of a high-prestress NPR anchor reduced the early deformation of the surrounding rock. The coupling failure modes of the arch tension extrusion failure and arch foot shear fracture occurred when the tunnel surrounding the rock was overloaded. The compensatory support system produces a bearing arch that is extremely resistant to external loads with minimal deformation of the tunnel surface and arch frame, excellent surrounding rock integrity, and a low stress rate. The radial and tangential peak stresses exceeded those of the passive support system, and the structural block fell when it became unstable. The maximum displacement of the arch stays constant at −5.7 mm after tunnel excavation. NPR bolts have remarkable applications in this field. The conclusions of this study have a significant impact on the regulation of the stability of the surrounding rock in large-span tunnels.

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NPR 螺栓补偿支撑系统下大跨度隧道断裂演化试验与现场应用

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来源期刊

Underground Space ENGINEERING, CIVIL-

CiteScore

10.20

自引率

14.10%

发文量

审稿时长

63 days

期刊介绍： Underground Space is an open access international journal without article processing charges (APC) committed to serving as a scientific forum for researchers and practitioners in the field of underground engineering. The journal welcomes manuscripts that deal with original theories, methods, technologies, and important applications throughout the life-cycle of underground projects, including planning, design, operation and maintenance, disaster prevention, and demolition. The journal is particularly interested in manuscripts related to the latest development of smart underground engineering from the perspectives of resilience, resources saving, environmental friendliness, humanity, and artificial intelligence. The manuscripts are expected to have significant innovation and potential impact in the field of underground engineering, and should have clear association with or application in underground projects.