Abstract: For safety in the construction of shield tunnels passing through pile foundations,this study investigates the change in tunneling excavation parameters in the shield tunneling project of the left section of Shenyang Metro Line 4 during normal shield excavation and pile excavation.The law of variation tunnel excavation parameters is investigated by the gray correlation method and the corresponding excavation parameter optimization plan is proposed.The study shows that the excavation parameters fluctuate greatly when the shield cuts piles.The excavation speed and the torque of the cutting head are reduced overall and the shield thrust is increased.The excavation speed should be controlled at 15~30mm/min,the torque should be controlled at 3 500~5 500kN·m,and the thrust force should not exceed 28 000kN when cutting piles.The foam injection amount is most correlated with the main propulsion parameters of the shield such as propulsion speed,thrust force,and torque,followed by the pressure in the bottom tank.During cutting piles,the shield should increase the foam injection amount and adjust the bentonite injection amount and consistency according to the changes of the main propulsion parameters to avoid the formation of mud cake at the cutting head.In practice,it has been proved that the shield can directly cut large-diameter reinforced concrete pile groups through reasonable adjustment of excavation parameters,providing a reference for similar projects in the future.