Abstract: The leading pipe shed is one of the most important measures to ensure the safety of shallow undergrouud excavation.For the miscellaneous land layer containing obstacles such as large stones,the construction of the pipe shed is very difficult.In order to solve this problem,the innovative construction technology of the impact drilling type advanced rotary nozzle shed is adopted.The pipe shed steel pipe is processed into a drill pipe,connected with the power head of the drilling machine,drilled through the dry impact,and crossed the design length of the street,and then a steel pipe with a closed plug is installed,and the steel pipe edge is further conveyed side by side.The rotary jet grouting forms a rotary lance shed,and the drill and short rod at the front end are unloaded one by one until the steel pipe with the plug is transferred to the opposite cut to form a full-length pipe shed,and the construction of the pipe shed is completed,and the rotary spray is expanded.Pre-supporting members with better grouting and better effect.The process is fast,safe and economical,and provides a favorable guarantee for the safe use of shallow burying under these conditions.

Key words: Advance pipe shed impact, Drilling spurt, Expansion, Shallow undergrouud excavation