Abstract: A group of micro steel pipe piles are selected in accordance with the surrounding environment and engineering geology of the project to underpin No. A4 pile foundation of No. A ramp of Guangzhou Inner Ring Viaduct Road. Calculation is made on the settlement of the pile foundation occurring after pile chiseling and shield passing. The calculated settlement value agrees well with the measured value, which shows that settlement calculation of the pile foundation is feasible and the micro steel pipe pile underpinning scheme adopted is feasible and rational.

Key words: shieldbored tunnel, micro steel pipe, pile underpinning construction, pile foundation settlement analysis