The new elevated bridge approach for Vietnamese bridge in Haiphong is relying on a Liebherr LB36-410 to complete piles drilling through waterlogged ground on schedule.
The Vietnamese ground engineering and foundations specialist contractor, Dua Fat Foundation Joint Stock Company, is relying on a Liebherr LB 36-410 rotary drilling rig to complete the 'lions share 'of bored piling in 'waterlogged-ground' conditions on the western approaches to a new road bridge over the River Cam in Haiphong in Vietnam.
The Hoang Van Thu Bridge will connect the centre of Haiphong to Thuy Nguyen, a north-west suburb with an expressway and provide easy access to a new riverside township Thuong Ly.
The 200 m span bridge includes a one km elevated western approach through cleared former mangroves which presented Dua Fat with considerable problems relating to the high water table, virtually on the surface - ensuring constant quagmire conditions.
The LB 36-410 rotary drilling rig is one of five rigs employed by Dua Fat on the Western Approach two month contract for 100 piles; with the Liebherr completing more than 80 per cent of the bored piles thanks to its power, flexibility and stability. Drilling through 50 m of waterlogged soil, soft sedimentary conditions and 10 m of soft rock, Dua Fat is drilling to depths of up to 62 m socketing into very hard granite-type rock. This includes 35 piles each 1.6 m diameter beneath the main column. The Project Vice General Manager, Dao Van Dat confirmed that the Liebherr LB 36-410 is taking just 20 hours to drill each pile. 'It is our preferred drilling rig since the other rigs take at least 28 hours to complete each hole in the tough waterlogged ground conditions.' The heavy-duty drilling rig LB 36-410 is used for bored piling using a variety of techniques such as Kelly drilling, continuous flight auger drilling, partial and full displacement drilling or double rotary drilling.
The drilling rig has been designed for easy transportation and fast set-up at the jobsite.
Despite its large machine class, the upper carriage is compact and designed for small working radii. Featuring an operating weight of 115 tonne the LB 36-410 offers a maximum torque of 410 kNm. Using Kelly bar drilling techniques, the drilling rig can be used to drill up to 80 m and a maximum drilling diameter of 3,000 mm.
Dua Fat upgrade LB 36
Dua Fat Foundation has recently completed modifications to one of its fleet of Liebherr drilling rigs and supervised by the Ha noi Representative Office of Liebherr-Werk Nenzing GmbH. Although only purchased in 2015, the company decided to upgrade an LB 36 with an extended Kelly bar; permitting increased drilling depths from 68 m to 72 m. The company also has a 'top of the range' LB 44 drilling rig.
The LB 36-410 rotary drilling rig is one of five rigs employed by Dua Fat on the Western Approach two month contract for 100 piles; with the Liebherr completing more than 80 per cent of the bored piles thanks to its power, flexibility and stability.