Research on Grouting Support of Large Pipe Shed Based on the Principle of ADECO-RS Approach

Choosing a suitable shallow-buried asymmetric tunnel entrance construction plan is the first step in tunnel construction. This paper takes Georgia’s E60 highway 3.0.04-AT tunnel T opening as an engineering case. Two opening construction schemes with or without advanced pipe shed support based on the principle of ADECO-RS approach are compared. The results show that: (1) The pipe roof pre-support can promote the formation of stress arches, improve the force of the advanced core soil and reduce the extrusion deformation; (2) Within the range of about 1 times the hole diameter of the tunnel face, the rate of settlement of the vault is the largest, and the amount of deformation reaches about 80% of the total deformation; (3) The pipe roof pre-support greatly reduces the plastic zone of the surrounding rock and avoids the plastic zone of the surrounding rock at the entrance of the cave from developing to the surface and causing the cave entrance to collapse. Finally, it can be concluded that the use of pipe roof pre-support at the entrance of the tunnel can greatly improve the stability of the surrounding rock and ensure the safety of the tunnel.