Experimental and numerical investigation of the effect of micropiles on soil improvement

With the increase of the population, the lands that are suitable for construction decreases, therefore, environmentally and economically important areas such as forests and agricultural lands are used for construction purposes and such applications are harmful to the environment. Alternatively, the construction of new floors above existing buildings is thought to be a suitable option for preventing the construction of new buildings. Additional floors lead to an increase in the loads that affect the foundations, and in such cases the soil underneath the foundation must be improved. Micropiles are widely used in many soil improvement applications to increase the bearing capacity of the soil and reduce settlement. Since micropiles are mostly made of steel material project costs increase as the number of piles increases. For this reason, within the scope of this thesis study experimental and numerical studies were carried out and compared to determine the effect of number and spacing of micropiles on soil reinforcement and bearing capacity to make more economical designs. A total of 48 experiments were carried out on 3 pileless and 45 pile combinations formed by placing micropiles at a distance of 4.5 cm on one, two, two opposite, three and four sides of raft foundations at different densities of sand (Dr= 10%, 40% and 65%). The results show increase in bearing capacity when the space between micropiles decreases, and also when the soil density, the number of piles and pile-driven sides increases. Comparisons show that the numerical and experimental results are compatible.