Pipe installation with GRUNDODRILL 11XP in redeveloped residential area
Three PE-HD DA 50 pipes were laid in the historic city centre of Dresden to accommodate glasfibre cables connecting domestic households to the new high-speed internet network (VSDL). To avoid any damage to the valuable road surfaces, the PE pipes were laid using trenchless technology in sections of 54, 112, 100 and 99 meter lengths. Customer M&M decided it was an ideal first job for their new GRUNDODRILL 11XP. The compact design makes the 11XP ideally suited for sites with restricted access, as commonly in inner-city locations.
The Dresden district of Löbtau is a popular residential area. The district which has grown naturally since the end of the 19th century, was reconstructed after the wall came down by renovating numerous blocks of flats from the Wilhelminian era, and some vacant lots were filled with new builds. Today, Löbtau has a multitude of shopping possibilities, parks, leisure facilities and very good transport links to Dresden's city centre.
The underground infrastructure has also been gradually adjusted to today’s requirements. Hence the street "Lübecker Straße" was to be connected to the broadband cable network in October 2015. To accommodate the fibre glass cables, three PE-HD pipes OD 50, from which the blocks of flats could be connected to the high speed internet (VSDL) via “FTTC”, had to ne installed.
With FTTC (“Fibre to the Curb“) the glass fibre cable is led from the exchange to the serving area interface and the signal is implemented via an optical-electrical converter. This way the rest of the route to the user can be covered with the existing copper cables and no new property service connections have to be created to make the high speed internet connection available. Thus this type of connection is mainly used for expanding the VDSL infrastructure in Germany.
In order not to break up the valuable new road surfaces again, the PE protection pipes over 54, 112, 100 and 99 meters length each were to be installed without trenches. The client HTP Hoch-u.Tiefbau Pfeffer GmbH awarded the contract to the special civil engineering company M&M Gesteuerte Bohrungen und Kabelbau from Löbau, who have a great deal of experience in underground pipe installation, in particular the HDD method.
M&M used the GRUNDODRILL 11XP for the first time. Due to its compact construction, it is particularly suited to drilling in very limited spaces such as inner city areas. Apart from the relatively limited space, the high number of existing lines and pipes as a particular challenge. False signals from overhead tram cables and the power supply for the signal technology made localization difficult and an oval profile drainage pipe ND 600 had to be undercrossed. Applying the latest detection technology, a Digitrak F5 system, the experienced bore crew were able to lead the bore path past the numerous obstacles as planned.
The actual pipe installation process went quickly and without any problems. The 80mm diameter pilot bore through the relatively hard subsoil was established in just 1.5 hours using the HDH bore head (HDH type 1) especially developed for very compact soils. Thanks to the good free cutting characteristics of the bore head and the perfectly mixed drilling fluid (100kg Bentonite in 4m³ water), no separate upsizing bore was required and the PE pipes were pulled in directly into the pilot hole in just 1 hour using a standard backreamer with rinsing grooves. The total of 365 metres of piping was installed in just 30 hours with the average installation speed being 12.16m per hour.
The project was carried out as a complete service with civil engineering in just three days, to the great satisfaction of the principal. Erhard Micklisch, owner of M&M was impressed with the technical benefits and the profitability of his new GRUNDODRILL 11XP.