Abstract: To improve the construction efficiency of the earth pressure balance (EPB)/single shield TBM doublemode shield machine in mode conversion and minimize the construction risk, a case study is conducted on the construction of the doublemode shield used in Liuxiandong stationBaimang station of Shenzhen metro line 13. According to the geological supplementary survey, ground survey, and chamber inspection, the conversion position of TBM mode to EPB mode is determined, and the three construction stages of the mode conversion are explained in detail. A set of mode conversion technology for doublemode shield tunneling in rock formations with obvious soft and hard boundaries is summarized. A series of works, including strengthening the supplementary grouting in the tunnel, complete preparation of tools and materials required for mode conversion, reasonable construction deployment, and optimizing belt conveyor assembly and disassembly process and screw conveyor tooling, have been employed before mode conversion, realizing a safe and highefficient mode conversion of doublemode shield with 3 and 2 days ahead of records of single modeconversion time and minimum conversion time in China respectively.

Key words: doublemode shield, earth pressure balance, singleshield TBM, mode conversion