The Ocean Deepwater Environment Pier Foundation Anti-erosion Techniques

Building the foundation of super-long pile in the deep ocean environment will change the originalmovement characteristics of sea water and cause local scour around the foundation of pile. For thesereasons, the thesis researched the local scour of bridge pier foundation and the technology of scourprevention in the construction of bridge pier foundation through theoretical calculation and fieldmonitoring, which combined with the engineering practice and tested bridge pier foundation in the actualengineering. The main results are as follows.(1) The thesis analyzed the actual situation of4#and5#pier foundation of Langqiminjiang bridgeand chose several kinds of theoretical formula which are relatively commonly used in China to calculatethe local scour of the sea surface around4#and5#pier, which found that the local scour depth of bridgepier foundation calculated by different theoretical formula has big difference. The calculation results canprovide certain reference for the safe design and protection of the bridge foundation of Langqiminjiangbridge.(2) Through setting measuring points of4#and5#pier branch bridge and actual height of the seasurface around drilling platform, it was measured that the actual scour depth of4#and5#pier foundationare4.05m and3.6m. But the local scour of the two piers are unfinished. In order to the continuousfunction of tide and tidal current at later period, the bridge pier foundation will continue to be scoured bythe seabed surface surrounding it until the local scour is completed. The local scour depth of the actualmonitoring can be used to guide the construction of pipe pile, steel tube and cofferdam for the purpose ofeconomy and safe construction.(3) The technology of scour prevention which is available for the construction of pier foundation indeep sea environment was proposed. According to the different level of riverbed and on the basis ofmeeting the conditions of construction, the correspondingly active technology of scour prevention wasadopted to reduce the scour of pile foundation during the period of construction in the maximum extentand ensure the smooth construction of pier foundation.One achievement of this thesis is providing certain reference value for the plugged depth of steelpipe and steel pipe pile in the construction of deep sea to ensure the safety of the pile foundationconstruction; The other one is adopting the technology of scour prevention during construction which canreduce the scour of bridge pier during the foundation construction and ensure the smooth construction ofbridge pile foundation, it has some practical value in engineering.