Research On Stiffness Characteristics Of Steel Sheet Pile Based On The Analysis Of The Friction Lock Between Piles

In recent years, steel sheet pile is used as a flexible supporting structure, it is widely usedin foundation excavation supporting, bridge cofferdam, ports and other projects. It has manyadvantages, such as easy construction, high strength, reusable, ect. Mainly rely on theconnection between the lock, a steel sheet pile wall is patched up by numbers of steel sheetpiles, then walls form an integral structure. Bending stresses are acted on the walls. It makesthe walls like a non-conventional type section composite beam. Research shows that the lockbetween steel sheet piles in the actual work will occur slip, this will lead that stiffness of thesteel sheet pile can not reach stiffness of the ideal pile wall, this phenomenon is called“Reduced Modulus Action”. Shear force is transferred between the lock of adjacent pilesdepend on the effect of friction. The value of friction is changed with the deformation of steelsheet pile.And it makes the mechanical behavior of steel sheet pile appearing nonlinear. In thecurrent design of steel sheet pile works, due to the impact of the RMA，it is inaccurate todetermine the accurate stiffness of the actual work steel sheet pile and calculate thedisplacementof steel sheet pile. This has brought great difficulties to the design of steel sheetpile retaining structure.First of all, we discusse the causes of stiffness nonlinear variation of steel sheet pile bythe knowledge of composite beams based on sectional characteristics of steel sheet pile, andobtain the variation of stiffness of steel sheet pile with movement of the neutral axis.Then, we establish the contact friction model by using the finite element software, obtainstiffness of steel sheet pile under different deformations, analyse the feature of stiffness ofsteel sheet pile with change of curvature, and discuss the impact of stiffness when the frictionbetween steel sheet piles change. In addition, we obtain the relation between the growth ofstiffness of steel sheet pile and curvature by analyzing curve of stiffness of steel sheet pile.Finally, we obtain the method to determine stiffness of steel sheet pile according to itscurvature by fitting curve of stiffness variation of steel sheet pile. At the same time, we givethe curve of stiffness of steel sheet pile with the change of moment and the curve of movingdistance of neutral axis with change of moment, so we can calculate the stiffness and theneutral axis position of steel sheet pile depend on the load that steel sheet pile suffer. Thus,these can provide relatively reasonable and feasible basis to calculate displacement and stressof steel sheet pile.