Field performance of underground structures during shield tunnel construction

This paper presents a case history of an earth pressure balance (EPB) shield tunneling constructed in a close distance near constructed underground structures in soft deposit of Shanghai. In order to protect existing underground structures, field observation was carried out, including reinforcement stress of interior structure and lateral displacement of the diaphragm wall. Throughout the shield tunneling construction, various countermeasures were adopted based on field observation feedback to minimize adverse environmental influences. The maximum cumulative lateral displacement of the diaphragm wall is about 11 mm. The maximum stress of reinforcement is 18.6 MPa, much less than the design value of steel tensile strength. These results and countermeasures are useful for engineers and technicians to select serviceable machine operation parameters and reduce environmental impacts during shield tunneling construction.

► We measured the responses of an underground structure during shield tunnelling.
► We analysed the relationship between the responses and parameters of construction.
► Monitored results were feed back to construction operation.
► Construction parameters were adjusted according to the monitored responses.