Constitutive Model and Experimental Study of Stud Steel-Shotcrete Interface Bond-Slip in Mining Method Tunnel Initial Support

Objective It is aimed to elucidate the constitutive relationship of bond-slip at the interface between stud steel and shotcrete in the initial support of mining method tunnel. Method Four different working conditions are set by varying the length, diameter, and arrangement of the studs. Push-out tests are conducted on steel-shotcrete short columns with studs on web plate, analyzing failure modes, load-slip characteristics and bearing capacity. Result & Conclusion The failure modes of stud specimens are affected by the number and strength of studs, categorized into tensile splitting and bursting failure. The typical average bond strength-relative slip curve can be divided into four stages: no slip, ascending curve, descending curve, and horizontal residual stage. Laboratory tests demonstrate that the diameter and arrangement of the studs are primary factors affecting the bearing capacity. A bond-slip constitutive model for the interface between stud steel and shotcrete is established based on stress mechanism, validated through both laboratory tests and numerical simulations, showing high accuracy. The research results can provide theoretical support for the design of steel and shotcrete support structures of mining method tunnels.