Sheet piles are pitched and driven to final level in one operation using a single ‘gate’ at ground level. The piles are gripped in the fail-safe hydraulic jaws and vibrated to level using a variable moment high frequency vibrator and also the crowd force of the machine. The telescopic leaders fully extend to facilitate the installation of piles of up to 16.0m in length driven with a MR 100V Vibro-driver. This resonance-free variable moment vibrator has a maximum centrifugal force of 100 tonnes and is one of the largest leader rig mounted vibrators in the country.
To assist with the installation of piles into dense gravels and stiff clays an auger motor can be fitted on to the telescopic mast to pre-drill the substrata and loosen the soils (using a 400mm dia. auger at 600mm clutch centres for ‘U’ piles). The RTG rigs have a distinct advantage over other types of leader rig in that the auger motor clamps directly into the jaws of the vibrator enabling very quick changes of the auger motor when difficult driving conditions are encountered. The base unit has retractable tracks resulting in a travelling width of only 3.0m and an all up weight of approximately 55 tonnes. Once on site, the mast is quickly erected and the tracks are extended to give a stable working width of 4.2m. However it is necessary to work close to the pile line and on the same level as the pile platform.