A scale effect on the geogrids produced with three-dimensional printer technology

Purpose: The aim of this study is to present the required coefficients and the change in ultimate values of mechanical properties of printed geogrids, in addition to evaluate the usability of three-dimensional printing technology within a field of reinforced soil or mechanically stabilized earth walls.Theory and Methods: Firstly, six types of geogrids were printed, which have 1/1, 1/2 and 1/4 scaling factors and two printing quality, via specified properties of printer due to requirements. Moreover, coupon specimens were produced to determine the tensile capacity of raw material. Then, all of them were subjected to tension tests as specified in ASTM D4595-17 [25]. Finally, shear box test were realized to obtain the shear strength parameters due to ASTM D3080 [26]. Results: It has been conducted that tensile strength capacity is decreased with the decrease in scale factor since the critical cross section against tension forces reduced. The tension force scaling coefficients were proposed between 0.15 and 0.41 due to printing quality and scale factor. The tensile strength of ABS filament was calculated around 14.6 MPa at 1.45% strain level. Although there is no significant difference in the average normal stress values at failure state, shear strength values of printed geogrids increased about 5%-15% within shear box tests with respect to original geogrids. Conclusion: The three dimensional printing technology can be used confidently to produce of geosynthetic reinforcements. However, the change in mechanical properties must be noted according to essential parameters such as raw material of filament, details of producing stage, size of geosynthetics and interactions between soils.