Study On Uplift Bearing Capacity Of Bucket Foundation And Its Influencing Factors

With the development and utilization of marine energy and resources,bucket foundation,as a foundation form of structure,is gradually widely used in ocean engineering with its unique advantages.In the service process,the bucket foundation is not only affected by the down pressure,but also by the uplift force under the load of storm surge,wave and current,which reflects the uplift bearing characteristics.The uplift bearing capacity of bucket foundation is related to the drainage condition,which is affected by the loading rate.In this paper,the finite element model of bucket foundation with different length diameter ratio is established by numerical calculation.By changing the parameters κ and overconsolidation ratio of soil,the influence of Cam clay model parameter κ and overconsolidation ratio on uplift bearing capacity of bucket foundation is studied.The specific research contents and results are as follows:(1)Through the finite element software ABAQUS,the numerical model of bucket foundation with different length diameter ratio and different pulling up rate is established.The failure mode of bucket foundation is analyzed,and the drainage condition is determined by the dissipation of negative pore pressure in bucket.There are three uplift failure modes of bucket foundation,including overall shear failure,bottom tensile failure and local shear failure,respectively corresponding to undrained and partial failure There are three drainage conditions: drainage and complete drainage.(2)The uplift rate of bucket foundation is normalized.Combined with numerical calculation,the uplift bearing capacity of bucket foundation with different length diameter ratio is obtained.The normalized uplift rate interval corresponding to three drainage conditions is determined,and the calculation method of uplift capacity of bucket foundation under different drainage conditions is proposed.(3)The influence of Cambridge model parameter κ on the uplift bearing capacity of bucket foundation is analyzed by numerical method.The influence of Cambridge model parameter κ on the undrained uplift bearing capacity and drainage condition of bucket foundation is analyzed.Therefore,the calculation method of bucket foundation uplift bearing capacity considering the parameter κ of Jianqiao model is proposed.(4)By changing the overconsolidation ratio of foundation soil,the influence of over consolidation ratio on the uplift bearing capacity of bucket foundation is analyzed by numerical method.The over consolidation ratio has influence on the fully drained uplift bearing capacity,undrained uplift bearing capacity and drainage conditions of bucket foundation.Therefore,a calculation method of uplift bearing capacity of bucket foundation considering the over consolidation ratio of foundation soil is proposed.