| Construction load such as the force induced by thrust jacks, operating load of erector in segmentassembly, the pressure by the tail grease and pushing force by tail brush and backfill injection pressure, may acttemporarily on the segment in the construction of shield tunneling. Crack or chipping on segment may occur dueto these construction loads, so it is important to clarify the impact on segments in terms of long-term durability ofshield tunnel. However, design method of segment considering the influence of construction loads is not established.When shield tunnel is constructed in deep and good ground conditions, the thickness of segment will bethin by expecting the action of soil and water pressure mainly and severer influence may be brought by constructionload. In this paper, the loads acting on the segments during construction under the pressure of the shield tailpassing through after segment assembly and under backfill injection pressure and so on were estimated by referringto the results of in-situ measurements in a shield tunnel passing through diluvial cohesive soil, and the impactof these construction loads on segment stress and ring joints was discussed by numerical analysis with the threedimensionalshell model. |
