HYBRID PIPE JACKING/DTH CONCENTRIC AIR POWERED HAMMER TECHNIQUE

Client: AC Srl Unipersonale – SIEMENS Spa – Italy

Year: 2011

What I did: I made the detailed design and work supervision of the installation, by hybrid pipe jacking/down-the-hole concentric air hammer technique, of three DN300 (12”) steel casings and the installation, by slip-lining, inside the 12″ steel casings, of three HDPE DN280 (11″) pipes, for the crossing of a rocky hill – Length of each crossing: 106,0 meters. The HDPE DN280 pipes, installed inside the 12″ steel casings, were used by SIEMENS to lay hi-tension electrical cables. A MITSUBISHI ULTRA MAXBIT 12″ were used to perform the boreholes.

HYBRID PIPE JACKING/DTH CONCENTRIC AIR POWERED HAMMER TECHNIQUE

$Longitudinal section of the crossing - the limestone was deeply fractured (RQD = 20%)$

Topographic survey of the rocky hill to cross.

The down the hole air powered concentric hammer - provided by MITSUBISHI

Scheme of the the down-the-hole concentric air powered drilling head, provided by MITSUBISHI.

Customized pulling head, to pullback HDPE DN280 pipes inside the 12

Detail of the pulling head before the assembling.