A flushing medium is needed to remove the cuttings from the advancing borehole produced by the drill bit to enable an efficient drilling performance and avoid jamming, as well as cooling the drill bit and ultimately reduce the wear of the bit.Three methods of flushing can be used:
Mainly for underground drilling in soil/rock formations or wherever there is an increased risk of soil mass instability. It avoids dust development in ventilated large cuttings and cooling of the drill bit.
Mainly for surface applications in all types of ground condition including swelling type clay and all other applications where excessive water spillage is to be avoided.
Simultaneous Drilling and Grouting:
Apply for both underground and surface applications in all unconsolidated soil conditions. Precautions are to be taken if large cracks or fissures are encountered through which the grout could be lost in the grounds thus not filling the annular space back to the surface.
Simultaneous drilling and grouting is today the most effective method for flushing and grouting in one single operation, it stabilizes the borehole during the drilling advance, provides for a high quality grout cover along the full anchor length, has a good penetration into the surrounding soil, thus improving the external interface between soil and grout and as such the friction values.
It is important to use a grout pump system that can regulate and control the flow and the pressure to minimize the waste and to maintain a constant flow during penetration.