Effect of connection and grouting level on mechanical behavior of pipe roof

ABSTRACT

Pipe roof support suffers from engineering defects such as connection and insufficient grouting in tunnel engineering. To analyze the influence of connection and grouting level on the mechanical behavior of pipe roof support during tunnel construction, a series of pure bending tests were conducted to measure the mechanical property of pipe roof, and quantitatively analyze the influence of the connection and grouting level on the bearing capacity and bending stiffness of the pipe roof. In addition, the double shear mechanical analysis model of pipe roof based on the Timoshenko beam theory and the Pasternak elastic foundation theory was established by considering the shear deformation of pipe roof, the supporting effect of surrounding rock of tunnel face and the delayed effect of shotcrete for primary support. Then, the solution methods for pipe roof deflection and internal force were derived based on this model. Based on an engineering case, the deflection and internal force distribution, as well as the effect of connection and grouting levels on the pipe roof were discussed. Corresponding construction suggestions were proposed and had achieved good results in the case. This research can provide reference for the design and construction of pipe roof.

CO EDITOR-IN-CHIEF:

• Ou, Yu-Chen

ASSOCIATE EDITOR:

• Ou, Yu-Chen

KEYWORDS:

• Pipe roof
• connection
• grouting level
• pure bending test
• double shear model

Acknowledgments

The authors gratefully acknowledge the financial supports.

Disclosure statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Data availability statement

The data that support the findings of this study are available from the corresponding author, Hu Ruiqi, upon reasonable request.

Additional information

Funding

This work was supported by the Jiangxi Key Laboratory of Disaster Prevention–Mitigation and Emergency Management Foundation under Grant [number 20212BCD42011]; and the Jiangxi Provincial Natural Science Foundation under Grant [number 20212BAB214013].