Aiming at the problem of large excavation settlement of shallow tunnels in weak strata, this paper takes Jiangbei Airport Tunnel as the research object. A three-dimensional finite element model is established based on ABAQUS to simulate the whole excavation process of the tunnel with and without the Pipe Roof Method (FPM). The influence laws of pipe diameter, pipe length, layout angle and transverse spacing on tunnel settlement control are analyzed, and the sensitivity of each parameter is quantified by the Settlement Reduction Rate (SRR).The results show that after adopting FPM, the vertical displacement of the tunnel portal vault decreases from 167.5 mm to 41.2 mm, and the maximum surface settlement decreases from 62.1 mm to 36.7 mm. FPM reduces the vault settlement by about 76% and surface settlement by about 41%, which can effectively transfer surrounding rock pressure to the primary support and improve the overall stability of the tunnel.Pipe diameter and pipe length are the most sensitive to settlement control, with SRR of 6.9%/cm and 4.8%/m respectively. The optimal parameter combination is pipe diameter 12 cm, pipe length 12 m, layout angle 6°, and transverse spacing 30 cm. The lap length ratio of pipe roof should not be lower than 25% to ensure the continuity and effectiveness of the pre-support system. Internal force analysis of the pipe roof indicates that the maximum axial force of 283 kN occurs at 1 m away from the tunnel portal. The research findings can provide theoretical basis and parameter reference for the design and construction of FPM in shallow tunnels within weak strata.