مدل سازي ديوارهاي خاكي مسلح شده با نوارهاي فلزي به روش اجزاء محدود

MODELING OF METAL-STRIP REINFORCED SOIL STRUCTURES USING THE DISCRETE ELEMENT METHOD

T he Discrete Element Method (DEM) was initiated in 1971 by Cundall, who studied the dynamic behavior o f rock masses. In his method , each single particle ist reated as a distinct elemeut . The new concept of DEM, in which each block of a soil mass is considered as an element, was presented by Chang, in regard to different geotechnical problems. In this research, DEM is used to analyze met al-strip reinforced soil structures. The whole reinforced earth wall is divided into trapezoidal elements ; each one containing a reinforcement. Norm al and shear Winkler springs are considered at th e sides of the elements to model interaction with adjacent soil blocks. Also, th ere are two ot her springs for the effects of metal strips in each element . The stiffness of the reinforcementʹs normal sp rings is calcul a ted by considering the friction of th e soil and metal strip surfaces. The shear force is obtained by considering the equation of an elastic bending and by replacing the soil with a series of elastoplastic springs . Then, the stiffness matrix can be obtained and, by applying the extern al force vector , displacements are found . The intern al forces at the sides of each element can be calculated by multiplying the stiffness of th e springs with the relative displacements of that side. A FORTRAN program is written to model different cases of reinforced earth walls. In orde r to verify DEM results, several examples have been analyzed and compared with ot her methods. In contras t with the difficulties and uncer tainties of convent ional methods , DEM can easily model the static and dynamic analysis of reinforced earth walls.