Time-Varying Response Analysis of Surrounding Rock Construction Mechanics of a Double-Arch Tunnel without a Middle Pilot Tunnel and Suggestions for Tunnel Construction

Abstract

AbstractThis research carries out the model test and numerical simulation, studying the time-varying response regularity of surrounding rock construction mechanics. The purpose was to ensure the construction safety of a double-arch tunnel without a middle pilot tunnel and to prevent rockburst or large deformations of surrounding rock in a stress concentration areas. To resist shear deformation of the steel arch of the first tunnel, during construction of the secondary lining of the lower step of the following tunnel near the side of the first tunnel, shear reinforcement is added to form a shear wall. To resist the stress of upward uplift in the inverted arch area, the spacing of steel reinforcements in the inverted arch is encrypted to reduce disturbance to the supporting structure. To reduce disturbance to the first tunnel caused by the blasting construction of the following tunnel, this article carried out the SHPB test on field rock samples and suggests that the reserve 2 m width of the surrounding rock (the lower heading of the following tunnel near the side of the first tunnel) is mechanically broken.