Experimental Evaluation of the Effects of Structural Parameters, Installation Methods and Soil Density on the Micropile Bearing Capacity

摘要

Recognition of the behaviour of micropiles under the influence of various parameters can help in the most efficient and optimal use of this improvement instrument. The present research conducted multiple static strain-control loading tests with a displacement rate of 10 mm/min and a laboratory program using a large-scale physical modelling device to evaluate various parameters such as the length, diameter, bond radius, and bond skin friction of micropiles in sandy soils with different relative densities. In addition, the load-bearing capacities of bored and driven micropiles were compared and the results demonstrated the effects of each parameter, as well as installation methods on the load-bearing capacity of the micropiles. The results show the significant role of the relative density parameter compared to other parameters in the values of the load-bearing capacity of the micropile. The results of the experiments further revealed that the diameter parameter has an average effect of about 12% more than the length parameter on load-bearing capacity values at different soil densities and the driven installation method can increase the load-bearing capacity up to a maximum of 84% compared to the bored method.