A 535 m (1'800 ft) long HDD bore was to be installed for a new waste water system on an island near Hong Kong. For environmental safety reasons the first 105 m (350 ft) beneath the mainland must be protected by a steel casing. To achieve this, a 1400 mm (55") steel pipe needed to be installed as an exterior protective sleeve for the first 18 m (60 ft). Thereafter a 1200 mm (47") steel pipe would be rammed into the sea bed for a length of 105 m (350 ft).
For this most challenging task, contractor Paul Y Construction Ltd. chose the TERRAHAMMER TR 565, which was affectionately nicknamed "the fat lady". Even with the ramming power of 2`400 tons this was a challenge for "the fat lady".
To facilitate the successful ram, TERRA's engineers proposed that Paul Y Construction undertake a lubricated pipe ram, using a specialised bentonite mix as is common in HDD drilling operations.
Following this methodology, the 1200 mm (47") steel pipe was successfully rammed in for the required 105 m (350 ft). A 350 ton pull-back HDD rig was then able top commence with the pilot bore for the new 800 mm (32") pipe, which was installed through the steel pipe rammed
