Reaserch On The Mechanism Of Structural System Of Sheet-pile Wharf In Yangtze River Of Anhui Province

To promote the economic development of Yangtze river of Anhui Province,we are planning the port development actively,increasing the tonnage of the wharves along the river of Yangtze river of Anhui Province gradually and optimizing the utilization rate of the shoreline by using the existing shoreline resources of Yangtze river of Anhui Province.Sheet-pile Wharf has the characteristics of saving coastline and lower cost,but its immature structure form and design technology is the important reason for limiting its development to deepwater.Therefore,it becomes an important research topic of exploring the deep-water sheet-pile wharves for Yangtze river of Anhui Province.In this article,we will select typical sand in Yangtze river of Anhui Province to measure the particle gradation,specific gravity,and relative density to obtain its physical characteristics.Triaxial test will be conducted to investigate its mechanical characteristics,and its parameters of Duncan-Chang E-B constitutive model will be deduced based on theoretical analysis.Making use of the ABAQUS software,the Duncan-Chang E-B constitutive model subroutine was compiled and the triaxial test model was established to verify the correctness of the secondary development and the accuracy of the constitutive model parameters.For unanchored sheet pile wharve,single anchor sheet pile wharve,covered type of sheet pile wharf,three-dimensional finite element numerical calculations will be conducted do the comparative analysis of the the mechanism of the three structures.The calculated value of the earth pressure on the front wall of the unanchored sheet pile wharve is similar to that of static earth pressure theory when the harbor basin excavation is shallow.The deeper the harbor basin is excavated,the more displacements of the front wall,and the bending moment will reaches the extreme value quickly.If the earth pressure on the front wall of single anchor sheet pile wharve is between the static earth pressure theory and the Rankine's earth pressure theory,the soil pressure curve on the front wall will be “R”.Along with the deepening of the harbor basin excavation,the maximum positive and negative values of the front wall bending moment constantly shift downwards.It's shown that the larger the displacement of the front wall,the greater the soil pressure and the maximum bending moment of the front wall will change.The tie rods can constrain the displacement and internal forces of the front wall during deepwater development.For covered type of sheet pile wharf,the soil pressure on the sea side of the barrier pile is significantly lower than that on the landside and the inter-pile side,with the deeper and deeper of the harbor basin,and the barrier pile can also reduce the soil pressure on the front wall.Comparing the calculation results of the three structural types of sheet pile wharves,the covered type shows a significant soil pressure reduction of the sheet pile wall comparing with the unanchored type and the single anchor type when the harbor basin is at the same depth,and the displacement of the front wall of the covered type is clearly reduced comparing with single anchor type,and its positive and negative bending moments are greatly decreased.The calculation results show that the unanchored sheet pile wharve is only suitable for the shallow excavation in the basin.While the depth of excavation along the harbor basin is shallow,the difference between the single anchor type and the covered type is not so obvious and the single anchor type gets more economic benefits.When the depth of excavation along the harbor is over 18 m,the mechanical performance of the covered type structure has obvious advantages in pressure bearing.It can withstand the soil pressure and bending moment generated by deepwater,and it has a distinct significance for exploring a deep-water sheet-pile wharf which is suitable for the economic development of Yangtze river of Anhui Province.