STUDY OF ESTABLISHED MECHANISM AND SETTING STANDARD OF CHAMBER EARTH PRESSURE FOR EARTH PRESSURE BALANCE SHIELD

The chamber earth pressure control is a key operation for controlling the impact of the earth pressure balance(EPB) shield excavation on the environment.Based on Shanghai Yingbinsanlu tunnel project constructed by a super-diameter EPB shield,the established mechanism and setting standard of the chamber earth pressure are studied by the theoretical research and measured data analysis.Relationships of the shield construction parameters are studied based on the soil in-out balance concept.The established mechanism of the chamber earth pressure is revealed according to introduce the soil compressing amount at the excavation face.A detailed model of shield cutter head is introduced to analyze the soil compressing amount at the excavation face caused by the cutter head.Based on the concept of controlling the secondary disturbance of the soil at the excavation face,a setting standard of the chamber earth pressure is proposed.The research results are applied and verified in the super-diameter tunnel,monitoring data shows that the settlement caused by shield tunneling construction is controlled effectively.