Geotechnical works.


The Mocaco bay growth

The Monaco bay growth will allow to build around ten villas with swimming pools, four blocks of flats, shops, and a marina. With its six hectares surface area, the project included the realization of a reinforced concrete caissons belt based on the RAC and RSC fills made of high granulometry materials. Concrete caissons have been built in Marseille, then floated and immersed in Monaco. Inside this belt, two type of technical fills with different granulometries have been backfilled (RTPC and RTPT).

Extension de l’Anse du Portier de Monaco

Embankment profile
RTPC : Current fills
RTPT : Technical fills
RAC + RSC : Concrete caisson fills

Backfills have been densified by vibrocompaction works and earthquake drains have been installed through the sediments to mitigate the liquefaction risk. The preparation and realization of the extension lasted 6 years between 2014 and 2020.

Many specific technics have been used to build this project:

  • Earthquake drains to give water a path to escape during a seismic event, preventing the buildup of water pressure in the soil matrix to mitigate the liquefaction potential
  • Vibrocompaction to densify the in-situ soils by vibration.
  • Stone columns formed by inserting a vibratory probe to incorporate granular material into the ground and create vertical inclusions with high stiffness, shear strength and draining characteristics


Some numbers

Offshore, 162133 m3 of materials have been compacted on a 13198 m² surface area and 1435 compaction points have been made
Onshore, 21007 m² were compacted with 1506 compaction points.

Number of Bottom Feed columns: 785
Treated length = 6 010 ml
Ballast volume = 2 460 m3
Incorporation rate = 12%

Number of Top Feed column = 366
Treated length = 3080 ml


Number of Earthquake drains = 1 109
Total length of drains = 30 610 ml
Treated surface = 9 050 m²