In the present study, the micropiled raft (MPR) systems have been modeled with the help of explicit 3D finite difference analysis method (3D-FDA). The 3D models have been subjected to both the compressive and tensile axial loadings separately and under the identical modeling conditions. The micropiles and the upper raft are simulated in a layer of stiff clay with su = 50 kPa. In numerical models, the length of the micropiles is Lmp = 10 m and their diameter is Dmp = 0.15 m. Distinctly, compressive loading was applied to investigate the settlement and tensile loading was imposed to evaluate the uplift of the MPR models. In 3D-FDA models, the six spacing configurations of the MPRs have been considered by selecting six center-to-center spacing, s, from 1 to 3 m between micropiles. Also, considering six parametric loading values on the MPRs from zero to a threshold of 300 kPa, a total of 72 numerical models have been implemented in this study. The ultimate bearing capacity values of the MPR models obtained from 3D-FDA for compressive loadings (Qucg) and tensile loadings (Qutg) have been compared with analytical results. There is currently an obvious research gap regarding the accuracy control of analytical relationships for estimating Qu for MPR models. In particular, so far the accuracy of analytical equations for calculating MPR compressive and tensile bearing capacities has not been compared with numerical findings. Besides, the axial stiffness of the MPR, kmpr, obtained from 3D-FDA has been compared with the results of the Poulos–Davis–Randolph (PDR) and Poulos–Davis–Randolph–Wood (PDRW) analytical methods. The results of this comparison confirm that the PDR and PDRW approaches obtain between 20 and 50% more conservative (lower) values for kmpr than the 3D-FDA. Moreover, the kmpr values obtained by PDR and PDRW methods differ with each other between 3.0 and 10.5%. On the other hand, the stiffness of MPR in tensile loadings is obtained three to four times greater than the stiffness of MPR in compressive loadings. Furthermore, a hyperbolic load–displacement curve with appropriate accuracy is proposed by performing curve fitting analyses, for both tensile and compressive loadings of the MPR.
