Optimal Analysis Of Sheet Pile Walls With Plastic Hinges In Clay And Sand

Conventional design methods for anchored sheet piles are only limited to single anchors.There is a need to accurately predict design parameters for double anchor situations as well as prediction of points of plastic hinge occurrence.The F has been utilized by researchers to study and understand the behavior of cantilever,braced,and anchored sheet pile walls under static and dynamic loading conditions.Although some researchers have proposed new design methods to solve double anchored sheet piles;this research has however modified the free earth support method for the single anchored pile to solve double anchored problems safely.This research was carried out by first validating the existing Das and Rowe combination for single anchored designs and to some extent investigates how soils with different properties affect bending moment.It was uncovered that the free earth support method for clays with low cohesion values would lead to an impossible quadratic equation whose three numerical coefficients are all negative.The next stage of the research is establishing sheet pile properties and excavation depth below the dredge level which are sufficient to sustain a safe wall.The FEA model revealed that the free earth support method sometimes produces unsafe designs,and use of piles with better stress properties was the only factor of safety used.Further investigation revealed that the free earth support method was limited to only walls no higher than 9m.However,the design parameters for shorter walls were consistent and were used to predict properties for higher walls.Since the anchor force on the first anchor has already been extrapolated from a reliable pattern,doubling(reasoned from the pressure diagrams and previous work)such force for the second anchor produces sheet piles that was structurally sound with excavation depths up to 18 m.In fact,all this was achieved by the use of the PZ22 profiles,which doesn't have glowing stress properties.It was found out the Rowe moment reduction curve for clays have a limitation as it is only suitable for clay soils with high cohesion values.Otherwise,what we have is “moment increment curve” rather than a “moment reduction curve.” There is stress concentration around the anchor levels which conforms to previous FEM studies.The stresses calculated from the finite-element analysis(FEA)were higher at the anchor level as well as toward the tip of the wall.All points were anchors are placed have a higher risk of plastic hinge occurrence.Besides this,points on the sheet pile at 0.8H are subjected to plastic hinge occurrence.This conclusion is within the scope of the piles and soil types analyzed.Finally,the points of plastic hinging are not affected by surcharge loads.For tieback walls,stress concentration would occur at the end of the lower anchors as well as the tip of the sheet piles.Their expected plastic hinging points are at 0.8H as well as 0.9(H+D).