Abstract: To improve the water conveyance capacity, the technical measures to reduce the roughness of the inner wall of the water conveyance tunnel are studied, and the technical measures to increase the flow section are replaced by brushing novel roughening material on inner wall. Based on a tunnel boring machine-bored long-distance water conveyance tunnel project in Xinjiang, China, 13 kinds of rough reduction materials are comprehensively compared from the aspects of appearance quality, on-site adhesion, and durability based on the environmental characteristics of low temperature and high humidity in the tunnel. The polymer inorganic network bond reduction material of the water-based system is finally selected, which can be cured in a timely manner, has good surface smoothness and flatness, as well as good bond strength and durability. The overflow capacity of the tunnel after roughening meets the requirements of the specification. Compared with conventional technical measures, rough reduction materials have the advantages of reducing potential safety hazards, convenient construction, shortening the construction period, and small investment. Through field tests, a complete set of innovative concepts are put forward for the technical measures of roughening the inner wall of the tunnel from the selection of materials and the detection of performance indicators, and the testing standards for the appearance quality and bond strength of roughening materials are put forward for the first time. The field test section has been fully operated according to regulations, and the appearance monitoring is good. In the later stage, it will be continuously monitored in combination with the water operation.

Key words: tunnel boring machine tunnel, free-flow tunnel, clearance margin, inner wall roughness reduction, roughening material