Assessment and Selection of Shield Segment Configurations and Assembly Angles Based on Circumferential Internal Force Analysis

This study aims to assess and select shield tunnel segment configurations and assembly angles based on the characteristics of circumferential internal force distribution. Based on the multi-hinged circular ring method and considering the diversity of assembly angles and segment configurations in practical engineering, a fundamental equation is established to calculate the contact forces at the longitudinal joints of a single shield segmental ring under arbitrary segment configurations and assembly angles. In addition, formulas for calculating internal forces are derived, and the corresponding coefficient matrix and constant vector are obtained, which significantly simplifies the process of solving the equation. Results from an actual project show that the calculated internal-force distributions are consistent with the expected mechanical response, while the calculated longitudinal-joint contact pressures show reasonable agreement with field measurements, supporting the reliability of the proposed method under the investigated engineering conditions. For the investigated circular segmental ring, the segment configuration and assembly angle significantly affect the distribution of internal forces. Moreover, appropriate configurations and assembly angles can effectively reduce bending moments and shear forces within the segments. When the segment configuration and assembly angle are fixed, external loads have a greater impact on the magnitudes of internal forces but less influence on their distribution. The selection of the segment assembly angle should be based on specific engineering objectives, such as structural performance and joint waterproofing requirements. The proposed method provides a basis for the assessment and selection of segment configurations and assembly angles, as well as for the design of longitudinal-joint waterproofing measures in practical engineering.