Micropiles allow solving some problems concerning the execution of foundations thanks to the possibility of using equipment having reduced sizes and encumbrance, and to the minimum disturbance caused to the soil and pre-existing structures.
MICROTREVI I is particularly suitable for being executed in soils that can be drilled by means of the rotation technique. In these cases, the same steel pipe making up the reinforcement of the micropile is used as drill string during the boring phase. To this aim, its bottom side is provided with a sacrificial three blades bit (drag bit). Close to the bonded length, the pipe is equipped with special non-return valves, "VELANOR" type, that are housed within the pipe thickness so that they are not damaged during the drilling phase. Said valves allow - whenever requested - to re-grout the micropile in a following time.
MICROTREVI II doesn't require the formation of a cement sheath for its execution, since the shaft of the micropile is plitted by means of bag packer. The single sections between bag and bag are subsequently pressure grouted. Said method assures an improved control over the grouting pressure and it allows grouting into those formations which would require excessive pressures due to the failure of the sheath, with following claquage risks.