(1) cofferdam must be able to withstand the various loads acting on it
(2) control the infiltration of cofferdam water, pump dry
(3) in each construction stage must ensure that the construction surface stability, does not occur uncontrolled uplift, quicksand or piping
(4) cofferdam wall and support deformation deformation can not affect the cofferdam near the permanent structure or other existing structures
(5) must ensure that slope or potential sliding surface lead to soil imbalance can maintain the overall stability of the weir body
(6) cofferdam size must be appropriate to meet the internal structure of the construction requirements:
(7) temporary cofferdam must be able to maximize the recovery and recycling of building materials broken
Design parameters of steel sheet piles cofferdam
In order to properly select the soil parameters of the proposed cofferdam site, the use period of the cofferdam must be determined. Because the cofferdam is a temporary structure, in most cases the total stress parameter can be chosen. Account the consolidation behavior of the cohesive soil, and if there is any uncertainty, the effective stress parameters should be used for checking.
According to experience, it is recommended to use the period of 3 months and more than 3 months of cofferdam using effective stress intensity parameters for size analysis. For clay containing silty interbeds, effective stress parameters should also be used for cold-formed steel sheet piles Cofferdams with shorter service life due to rapid drainage.