Shield segment structure and shield tunnel

The invention discloses a shield segment structure and a shield tunnel. The shield segment structure comprises a plurality of segments, wherein the segments are defined and spliced to form an integral ring; a cross section of the integral ring is a centrosymmetric and axisymmetric special-shaped face; the special-shaped face is formed by defining eight inferior arcs; the eight inferior arcs are a top inverted arch and a bottom inverted arch which are arranged vertically, oppositely and symmetrically, a left arch and a right arch which are arranged horizontally, oppositely and symmetrically, and four corners respectively; the segments are centrosymmetrically distributed on the integral ring; spliced seams, located on the cross section, of the adjacent segments are staggered with maximum internal force parts of the corners, and symmetry axes; a plurality of shield segment structures are butted to form the shield tunnel; and the spliced seams of the segments of the adjacent shield segment structures are arranged in a staggered manner. The shield segment structure and the shield tunnel can well integrate factors such as transverse internal force distribution of the shield tunnel, and connection of the longitudinal segments, so that the shield segment structure and the shield tunnel have good integrity, high efficiency and implementability.