Behavior of soil reinforced with micropiles

Soil investigation is very important to check the bearing capacity before constructing any structure. There are different types of soils that cause many problems for the structure in short and long term, which are known as problematic soils. A lot of researchers dealt with improvement and reinforcement of the problematic soils by physical and chemical treatments. The objective of this study is reinforcing the problematic soil with micropiles with different depths and different configurations. In this study, two types of soils, soft clay and loose sand, were used to study the effect of adding micropiles of different depths and different configurations to investigate the best improvement of bearing capacity for shallow foundations on these soils. The results showed that reinforcing the natural soil with micropiles could improve the pressure carrying capacity of the problematic soils. When the design width is changed from under foundation alone to under foundation and 2 B width, the soil reinforced with 2 B depth of micropiles can raise the soil’s load carrying capacity by 45 to 65% when compared to untreated soil. Just 7% more bearing capacity may be achieved by increasing the depth of the micropiles from 2 B to 3 B (where B is the footing width); as a result, going deeper than 2 B is not advantageous. Additionally, the bearing capacity of the micropiles increases by only 3% when the breadth of the configuration is increased from 1 B to 2 B ; so, wider configurations than 1 B are invalid.