Research on Construction Technology of Composite Steel Cofferdam under Special Conditions

On the basis of existing research, in response to the widespread application of steel sheet piles with low stiffness, the high stiffness but poor economic efficiency of locking steel pipe piles, and the difficulty of water sealing, combined with engineering examples, the construction plan was optimized and studied for special conditions such as the cofferdam structure being too close to the water pipe, the foundation pit of the pier being deep and large in area, and the complex geological structure of the riverbed.Innovatively proposed the construction technology of a combination of steel pipe piles and steel plate piles for an "8" shaped cofferdam.The use of precise positioning method for cofferdam steel pipe piles has innovatively solved the problem of difficulty in controlling the spacing between cofferdam lock buckle steel pipe piles; The lock mouth was filled with a mixture of 50% stone powder, 25% putty powder, 20% sawdust, and 5% cement, successfully solving the problem of water seepage in steel pipe piles; The design of using steel pipe piles and steel plate piles to join the "8" shaped cofferdam greatly saves the amount of steel pipe piles and overcomes the problem of small spacing cap cofferdam structure construction, greatly improving the economy and construction convenience.This technology has been successfully applied in a project of the southern section of the Dongxiaonan Road-Guangzhou South Station connection line, with a qualification rate of 100% for all indicators, achieving good economic benefits having good promotion and application value.