Analysis on the Influence of Geometric Parameters of a Circular Steel Pipe with Flange Plates on Surface Settlement

Abstract

Surface settlement is considered a key indicator in the pipe jacking procedure of the steel tube slab (STS) pipe-roofing method. Commonly, the existing equations for this safety indicator are applied in the process of measuring surface settlement caused by the pipe with circle or rectangle cross sections. This paper proposes calculation methods for the surface settlement of a circular steel pipe with flange plates based on the modified Mindlin solution considering pipe–soil interaction and the influence of flange plates. The proposed equations in this paper are applied to calculate the surface settlement for the actual pipe jacking engineering in Shenyang, China, and the calculated results fit well with the field monitoring values. This paper analyzes the main geometric parameters affecting surface settlement, including the orientation of flange plates and pipe specification. Simultaneously, this paper obtains the mathematical relationships between the surface settlement and the geometric parameters, providing a theoretical prediction method for actual pipe jacking construction of the STS pipe-roofing method. The development of metro construction has become one of the indications of urban progress. How to build metro projects efficiently and safely has become one of the main problems of underground engineering. The steel tube slab (STS) pipe-roofing method is a new method of constructing urban underground space, which not only enhances the sideways stability of the conventional pipe-roofing system but also effectively regulates the subsidence of the ground during underground digging, thereby augmenting both the horizontal and the vertical load-bearing capabilities. This method has already been efficiently employed in the construction of the subway stations of Shenyang Metro Line 9 and Line 10. This paper proposes calculation methods for the surface settlement of a circular steel pipe with flange plates based on the modified Mindlin solution considering pipe–soil interaction and the influence of flange plates. This paper analyzes the main geometric parameters affecting surface settlement, including the position of flange plates and steel pipe diameter. Simultaneously, this paper obtains the mathematical relationships between the surface settlement and the geometric parameters, providing a theoretical prediction method for actual pipe jacking construction of the STS pipe-roofing method.