RESEARCH ON PROPERTIES OF DEFORMATION AND MECHANICS ON DOUBLE-ROW PILE STRUCTURE WITH FLAKE TOP BEAM

The 3D FEM software MIDAS-GTS was used for establishing numerical analysis model of double-row pile structure with flake top beam，in which practical soil layers，solid supporting structures，Goodman contact elements and actual construction stages were simulatneously considered． The resulted of the study showed that the horizontal displacement of supporting pile was strongly limited by flake top beam when the size of deep excavation was not large enough． The maximum values of bending moment and shearing force of top beam always appeared near the corner of the excavation． Along with change of the length of top beam，while other parameters were fixed，the curves of horizontal displacement and shear force of top beam were just single variable function with only one argument (horizontal displacement from the corner of the excavation)，which little related with the length of top beam． When the hight of top beam was raised，the bending moment and shearing force of top beam were highly increased but the decrease of horizontal displacement of top beam was not sharp． Along with increasing of the depth of the excavation， the value of bending moment and internal force in the middle of top beam rose obviously． While the distance between the front and back pile increased，the value of bending moment and internal force in the middle of top beam decreased，yet，the rate of reduction also decreased． The increment of the distance between the front and back pile impacted the bending moment and internal force of top beam slightly．