套筒强夯长短桩复合地基承载特性研究OACSTPCD

[Objective]With the accelerated construction of a series of large-scale ocean projects,new challenges have been pres-ented to the treatment of underwater soft soil foundation.The traditional method such as underwater compacting sand pile and un-derwater cement mixing pile composite foundation are difficult to locate and make columns,poor column quality and other disad-vantages,which always restrict their application and development in ocean engineering.[Methods]Based on the construction method of deep dynamic compaction in hole on land,this paper proposes the method of underwater dynamic compaction in com-posite foundation.The technology uses tube to block seawater from entering column hole,which has the advantages of accurate positioning,deep reinforcement and high strength.In this paper,the technology was investigated by means of modeling experi-ments.[Results]The result show that,under the condition of combination of dynamic compaction stone column and traditional stone column,increase in ultimate bearing capacity of foundations by more than 50％,the ultimate bearing capacity of equal length column group composite foundation is 18％higher than that of long-short-columns composite foundation.Under the condi-tion of combination of dynamic compaction stone column,increase in ultimate bearing capacity of foundations by more than 170％,the ultimate bearing capacity of the composite foundation with the same length column group is 3.7％higher than that of the composite foundation with long-short-columns.[Conclusion]The bearing capacity of composite foundation made of all dynam-ic compaction stone columns increases more than that of composite foundation made of dynamic compaction stone columns and traditional stone columns.The use of stone long-short-columns by underwater tube dynamic compactions more cost-effective in improving bearing capacity.