Full-scale field testing for optimising foundation design in road and railway construction in Norway

By Thi Minh Hue Le, Christian Strømme Ofstad & Jean-Sebastien L'Heureux, NGI

Full-scale field testing in operational environment is an important step in order to optimize the design of possible foundation solutions. NGI has a long record and extensive experience with field testing of foundations for different national and international projects. Particularly, NGI has conducted full-scale test of embankments and pile foundations in a number of roads and railway construction projects in Norway.

Between 2019 and 2020, NGI performed full-scale testing of both embankment and pile foundations at Mælingen, around 60 km northwest of Oslo. Three 10 m high embankments were constructed, and pipe piles with diameter between 40 and 80 cm were driven to 40-90 m depth in two areas. The test embankments and the piles were installed with various sensors and monitoring equipment including piezometer, inclinometers and sensors for monitoring deformations and settlements. These full-scale tests were conducted to gain more information for the choice of foundation design for bridges in the area. The tests have indicated that shallow foundations will give acceptable settlement and may be a suitable solution for the bridge foundations. This solution will be significantly more economical compared with using a large number of friction piles. The potential saved cost can be as much as 30-35 million euros by using shallow foundation instead of piles.

The test program is part of a combined construction project (FRE16) of 40 km double railway track from Sandvika to Hønefoss at 250 km/hour (Ringeriksbanen) and 15 km four-lane highway between Høgkastet and Hønefoss (E16). FRE16 is the largest combined project between road and railway in Norway and is part of the Norwegian National Transport Plan.

NGI, GEOLAB project’s consortium partner, is an independent international centre for research and consultancy in engineering-related geosciences, integrating geotechnical, geological and geophysical expertise. The Geotest sites research infrastructure managed by the NGI is a national research facility for geotechnical research. The six benchmark test sites are located in Norway and on Svalbard and have been developed as field laboratories for the testing and verification of innovative soil investigation and testing methods, and prototypes of geotechnical structures.