Abstract: The small pipe-roofs method effectively controls soil deformation,shortens construction period,and offers significant advantages in the development of underground spaces.Accurately predicting the deformation of small pipe-roofs is crucial for managing soil deformation.In this study,a deformation calculation formula for small pipe-roofs was derived based on the small deflection theory of elastic thin plate,considering the actual stress characteristics.The article further proposed a method for calculating the bending stiffness of pipe-roof structures and validated this approach by comparing it with laboratory test results.Additionally,the influence of key parameters on the deformation of small pipe-roofs was analyzed.The findings indicate that the proposed deformation calculation formula for pipe-roofs is reasonably accurate.The results show that the diameter of the steel pipe,the elastic modulus of the grouting material between the pipes,and the span of excavation significantly affect the deformation of the pipe-roof.Specifically,the maximum deformation of the pipe-roof exhibits a power-law decrease with the diameter of the steel pipe,a linear decrease with the elastic modulus of the grouting material,and an exponential increase with the excavation span.When the diameter of the steel pipe increases from 350mm to 600mm,the deformation of pipe-roofs decreases by nearly 80%.When the elastic modulus increases from 5GPa to 25GPa,the maximum deformation of pipe-roofs decreases by more than 40%.These research outcomes provide valuable reference and guidance for future studies in this field.