Definition of the safety distance between the palm face, inverted arch, and secondary lining under the parameter constraints of mechanized construction equipment

In the mechanized construction of tunnels, due to limitations in mechanical equipment parameters, the distance from the palm face to the inverted arch and secondary lining does not meet the safety distance specified in the regulations. In order to obtain the deformation of surrounding rocks and the stress laws of support structures under the safety distance out of specification of mechanized construction, the paper first analyzed the parameters of mechanized construction equipment and the safety distance of adjacent equipment. The safety distance between the three arm rock drill trolley equipment parking area and the inverted arch was 50 m, and the safety distance to the secondary lining was 150 m. The distance from the palm face to the inverted arch and the secondary lining needs to increase the distance of the blasting flying stone based on the original safety distance. Then, based on the Qilinguan tunnel, numerical simulation was used to study the distance from the palm surface to inverted arch and the secondary lining. The results showed that the deformation difference of surrounding rock and the force difference of supporting structures under different distance from the palm face to the inverted arch and the secondary lining obtained in the paper were small, and the deformation of surrounding rock is within the allowable range of the specification. Finally, the rationality of numerical simulation and the distance from the palm surface to inverted arch and the secondary lining was verified. The research of the paper can provide reference for mechanized tunnel construction.