Transport infrastructure - roads and railway systems - are frequently built in areas where the soil is highly compressible, such as swamps, marshes or areas near watercourses. In such cases, substantial consolidation work is required to avoid shear failure of the fill used to build the structure. This type of project requires simultaneous management of multiple sites along the alignment and can often involve the use of a variety of solutions to meet the wide-ranging geotechnical conditions and specific constraints of the terrain. To ensure the long-term integrity of the infrastructure and the safety of the vehicles using it, it is essential that these areas are “over-consolidated” to reduce settlement due to primary settlements, creep and to limit differential settlement. For engineering structures built along the alignment, backfill generates very high loads associated with strict settlement limitations. These critical areas generally require even more extensive treatment and careful management of the interfaces.
CASE STUDY: SOUTH RING ROAD OF GDANSK, POLAND
The Ring Express road joins the existing 3-city Bypass (Gdańsk, Sopot and Gdynia) and the Highway A1 (Gdańsk – Katowice) in the North of Poland.
This area had extremely bad soils conditions for road construction. There was very organic soil (peat and sludge) with high water content index. The thickness of weak deposits varied from 6 to 25 m with average depth of 12 m.
Two ground improvement methods were proposed: Controlled Modulus Columns and pre-consolidation treatments using vertical drain with surcharge. This solution fulfilled the technical and economical requirement of the investor.
6 to 25 mDepth
Vertical drains & Controlled Modulus Columns