Research On Bearing Characteristics Of Offshore Deep-water Wharf Considering The Weakening Effect Of Soft Clay Strength And Rigidity

The all-vertical-pile wharf structure is a new type of structure suitable for offshore deep-water wharves on soft soil foundations.The structure has been in the seas with high wave cyclic load intensity for a long time,and the long-term wave cyclic load has caused significant strength softening and rigidity weakening of the cyclic softening effect of the foundation soil.However,the load-bearing characteristics of the offshore deep-water all-vertical-piled wharf structure due to the strength and stiffness softening of the saturated soil are still unclear.To address this problem,this paper combines an actual offshore deepwater all-vertical-pile wharf structure,based on the secondary development platform of ABAQUS finite element software and Fortran language,to prepare the calculation program of strength and stiffness attenuation of saturated soft clay,and establish the finite element calculation model of structure-foundation interaction.A more systematic study on the structural bearing characteristics,damage modes and stability factors of offshore deepwater all-vertical-pile wharf structure considering the softening effect of soft clay strength and stiffness is carried out.The specific research contents and related conclusions are as follows:1.Firstly,a three-dimensional elastoplastic finite element model of the structure-foundation interaction of the offshore deep-water full vertical piled wharf was established through the ABAQUS finite element analysis software,and the wave load calculation subroutine was compiled using Fortran language.Then,using the load control method,the wave force,impact force,the horizontal effect of wave force and the coupling effect of the impact force,and the impact effect of the wave force on the panel and the coupling effect of the impact force on the structure under the force,deformation and instability damage are calculated respectively.mode.The results show that the coupling effect of wave force on the panel and the impact force has the greatest impact on the stability of the structure,and the safety factor of the structure is reduced by 13.1%.2.Secondly,based on the existing test results,the saturated soft clay stiffness attenuation model and the method for determining the relevant parameters in the model are fitted to the saturated soft clay considering different cycle times,different dynamic deviator stress levels,and different pore water pressure conditions.stiffness attenuation law model.And with the aid of the ABAQUS finite element secondary development platform,the stiffness attenuation model is embedded into the established numerical calculation model,and the existing cyclic triaxial test results considering the stiffness attenuation characteristics are simulated,and the results are verified by comparison with the existing test data.The correctness of the stiffness attenuation model established in this paper is verified.3.Finally,the above-established stiffness attenuation model and the existing strength weakening model are simultaneously embedded in the offshore deep-water full vertical piled wharf structure-foundation three-dimensional elastoplastic finite element calculation model,and the saturated soil strength softening and stiffness weakening are considered separately.And considering the strength and stiffness weakening at the same time,the comparative analysis of the force and deformation of the offshore deep-water full-pile wharf structure and the foundation soil.The results show that the structural safety factor is reduced by 23.6% when the soil strength is softened under the same number of cycles,the structural safety factor is reduced by21.9% when the soil stiffness is weakened,and the structural safety factor is reduced by 33.9% when the soil strength and rigidity weakening are considered.It can be seen from the above results that it is necessary to consider both the strength and stiffness of the foundation soil at the same time.