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Abstract Some key issues including inner and outer influencing factors of trench face stability，overall and local instability mechanism of trench face，and stress path of soil element near trench face are discussed in detail to investigate the trench face stability and instability performance during slurry trenching for diaphragm wall panels. The research results show that shallow ground collapse is the major trench face overall instability pattern during slurry trenching，and trench face local collapse is commonly caused by heavily sandy of soil and excessive fluctuation of slurry flux level. Some precautionary construction measures，including increasing unit weight of slurry appropriately，raising slurry fluid level，pre-reclamation of trench face soil，control of trenching machine overloading and manipulation of soil disturbance during slurry trenching，are the most effective countermeasures to ensure the trench face stability. The trench face stability decreases with the dissipation of negative pore pressure after slurry trenching. Therefore，reinforcement cages should be placed into trench in time and concrete should be casted as soon as possible to guarantee the trench face stability.
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Received: 16 August 2012
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2013, Vol. 32 
