During shield construction there are many segmental partial ruptures caused by construction factors which is already confirmed by engineering practices. The segmental mechanical characteristics during construction stage are presented firstly; and then common local ruptures of segment concrete are summarized; and leading causes are analyzed. And based on which mechanical model for construction stage is developed. The model can be described as a fixed-simple component which one end is anchored by clotted grout and the other end is supported by shield sealing brushes. In order to study the segment mechanical properties

a shield tunnel as an example is analyzed; and several cases are simulated by FEM; then comparison between FEM results and field measurement values is made. Study has manifested that most segmental ruptures are located at the fifth ring to the seventh ring which is approximately same to in-situ rupture position of segment. In addition

thrust force and its obliquity and partial difference are the main causes leading to segmental rupture. Finally

some items are suggested to lighten local ruptures of segment during shield construction stage.