Research On Horizontal Ultimate Bearing Capacity Of Skirted Suction Bucket Foundation

Suction bucket foundation has the advantages of high construction speed,low construction cost and reusability.It has been extensively used in offshore engineering in recent years.However,due to the weak horizontal bearing capacity of the suction-type bucket foundation,and the offshore engineering structure is subjected to horizontal loads such as wave loads and wind loads in the marine environment for a long time,overturning damage is likely to occur in actual engineering.In response to the above shortcomings,the scholars made further improvements on this basis and proposed a "skirted suction foundation" with improved structural form.The new foundation has good continuity,the horizontal bearing capacity is significantly improved,and the lateral displacement is effectively limited.It is especially suitable as the basis for structures such as offshore wind power towers whose main load is horizontal load.The theoretical analysis and structural calculation of the foundation are not yet mature,and the research on the performance of soft clay has not been reported.The theoretical analysis and experimental research will provide the necessary theoretical basis for the application of the new foundation in practical engineering.In view of this,this paper studies the mechanism of the interaction between skirt suction foundation and soil,and analyzes the law of soil pressure,side friction and foundation reaction force inside and outside the barrel structure during horizontal loading.The main contents of this paper are:(1)A three-dimensional nonlinear finite element numerical model is established for the interaction between the skirt-type suction bucket foundation structure and the soil,and consider the calculation domain,boundary conditions,soil and barrel structure contact settings to reflect the actual working conditions of the structure.The results obtained are compared with the experimental data in the literature to verify the correctness of the numerical model.(2)Horizontal static loading of skirt-type suction bucket foundation model with different skirt sizes,analysis of the combined effects of soil pressure,barrel side friction resistance and foundation reaction force of different skirt sizes,and the study of skirt height The influence of the skirt width on the basic horizontal bearing capacity.The soil in the barrel is analyzed to participate in the anti-rolling mechanism,and the soil pressure is numerically simulated and compared with the traditional soil pressure formula.The study found that both the skirt-type bucket foundation and the traditional bucket-shaped foundation failure mode are rotated around a certain point in the barrel,and the horizontal ultimate bearing capacity of the skirt-type bucket foundation is obviously improved;as the size of the bucket skirt increases,the barrel base and The area of the foundation action increases,the range of deformation of the foundation soil increases significantly,and the displacement in the limit state also decreases.(3)For the same group of skirt foundation structure,change the value of soil friction angle ψ,elastic modulus E and cohesion c in the model,and analyze the parameter sensitivity to analyze the horizontal bearing capacity and displacement of each parameter.(4)According to the limit equilibrium state of the skirt bucket foundation under the horizontal load,the bucket structure is subjected to force analysis.According to the numerical simulation results,the rotation point of the bucket structure overturning is calculated,and the skirt suction foundation of the bucket foundation is established.The instability of the model is calculated and the theoretical formula is derived to verify the accuracy.