Abstract:

The 5^# and 6^# cofferdams of Xingguang Bridge are retained by steel sheet pile walls and steel struts struc-ture.Rock powders are used to resist the seepage force.In this paper,the optimal design of the retaining structure is introduced.A comparison between the designed results and the monitored results is also carried out to investigate
the main causes of the obvious differences in pile deformation.It is found that(1)during the initial loading of steel sheet pile walls,the slippage of piles occurs,which results in a great decrease in the total rigidity of the walls and brings about a deform ation larger than that of the designed value;while in the later loading phase,the interaction between piles increases and the relative slippage is restricted,thus resulting in a recovery of the total rigidity and a deformation increment similar to the designed one;and(2)the deformation mainly centers around the joints be-cause the rigidity of longitudinal joints between piles is weaker than that of piles.It is thus concluded that,when designing a retaining system,the wall module should be varied according to the loading phases of piles,and that the safety coefi cient of steel struts should be larger than that of steel sheet piles.

Key words: steel sheet pile, cofferdam , optimal design, monitoring