Comparative study on control effect of deep roadway under full-length prestressed bolt-grouting support

This study proposed the numerical simulation method of full-length prestressed anchor grouting support based on the post-grouting technology, and the modification of the embedded PILE structural unit in FLAC^3D software. Specifically, we conducted the numerical simulation and made comparison in terms of the control effect of roadway surrounding rock under six types of factors: ground stress, strength grade of original rock, length of supporting members, layout spacing, grouting strengthening index and prestress, with the aim to reveal how these factors affect the deformation of surrounding rock and the evolution of plastic zone. Then, we proposed the sensitivity evaluation index of control effect under full-length prestressed anchor grouting support. The influencing factors are divided into 3 levels: strength of surrounding rock, ground stress and design of bolt-grouting support members. Suggestions for engineering are also given according to the sensitivity level of each factor. Finally, the combined high-strength grouting bolt and high-strength hollow grouting cable are developed based on a typical roadway in weak broken strata. It can effectively enhance the self-carrying capacity of weak broken surrounding rock, give full play to the supporting potential of anchoring members, and limit the deformation and failure of roadway surrounding rock. Through the field application, the full-length prestressed bolt-grouting support is verified.