Design And Operation Evaluation On Bionic Spudcan Of Jack-up

The current jack-up has disadvantages of low coupling stiffness between pile and soil,high probability of punch-through and sliding accident,worse uplift capacity and so on,which could not meet the requirements for deep trend and safety of drilling operation.Therefore,compounded bionic idea is put forward to carry out research on compounded bionic mechanism for snail-egg shaped spudcan of jack-up in limit water depth,based on streamlined profile of egg shell and special positive Gauss surface of snail shell.The specific contents are as follows:(1)Based on the snail shell spiral surface,suture and egg shell shape,carry out contour scanning test respectively.The statistical shape features can be received.By HyperMesh software to extract feature points,using the mathematical expression of Origin software is derived and fitted with two helix,three helix and the requirements of the body whorl shell contour.Finally combined with the Matlab software and the Pearson correlation coefficient to verify the curve,curve and ensure highly consistent biological prototype.(2)Through the analysis of the existing spudcan bearing capacity formula,research single-layer and multi-layer foundation resistance.Then using the cavity expansion theory deduced inserted resistance based on SMP criterion,and compared with the soil test.And analyze the theoretical formula of resistance at home and abroad.Finally,the feasibility of the theoretical formula and the feasibility of the bionic spudcan are analyzed.(3)Combined with the characteristics and function of body whorl,snail shell shaped is established on lower part of spudcan.Combined with the eggshell and egg shape features of blunt end function,egg shell shaped is established on upper part of spudcan.Research on bionic composite mechanism between snail shell model and egg shaped bionic model,establish a "snail-egg" shaped composite model of spudcan.The use of boots and soil mechanical behavior of bionic spudcan analysis method,by the method based on Abaqus numerical analysis,study qualitative relationship between "snail-egg" bionic spudcan inserted load and the depth of insertion.Finally,the failure mode of soil flow is studied,and the influence mechanism of soil flow failure on the pile load is analyzed.(4)By Abaqus numerical analysis method,study the influence of the platform pullout resistance under the condition of non seepage stress coupling.Secondly,through the finite element method,the research of two kinds of spudcan pore pressure changes under the surface can be analyzed;finally,study the pile soil flow conditions and failure modes,and study the influence mechanism between the soil flow and pullout resistance.