Techniques

Soil improvement

Soil-improvement techniques involve changing soil characteristics by a physical action, such as vibration, or by the inclusion or mixing in the soil of a stronger material. The aim of this process is as follows:
- increase the load-bearing capacity and/or the shear strength,
- reduce both absolute and differential settlements or in certain cases, accelerate them,
- to mitigate or remove the risk of liquefaction in the event of an earthquake or major vibrations.

The scope of application of the various techniques depends mainly on the type and grading of the soils that require improving.




Dynamic compaction and replacement
This method allows the treatment of the ground at depth, through surface action. Dynamic consolidation provides the compaction of loose granular soils.
The principle consists of dropping, in repeated free fall, a weight of several tons from a height some of ten meters or more.
On clayey soils, stone is placed across the site under the mass, making the dynamic replacement effective.

Vertical drains
Vertical drains are used to improve saturated fine soils. The technique consists in driving prefabricated drains vertically into the ground, following a regular grid. When the ground is loaded, the drains aid the evacuation of the pore water to the surface, allowing rapid consolidation of the ground. The surcharge is provided either with a pre-loading fill, or with other methods.

Vibroflottation
Vibroflotation (sometimes called vibrocompaction) is applied essentially to granular and non-coherent soils, such as sands and gravels. The vibrations induce a temporary liquefaction of the soil around the vibrator. In this case, the intergranular forces are temporarily nullified, and the grains are rearranged in a more compact pattern offering better characteristics.
This technique is often used on large works for the densification of hydraulic fills for reclamation..

Stone columns
The stone columns process is an extension of vibroflotation for ground containing silty or clayey layers, the particles of which cannot be rearranged by vibration. Stone columns allow the treatment of these types of ground through the incorporation of granular materials (sometimes called ballast) compacted from the bottom up. These columns can also be either concreted or made of mortar. They also serve as drains and allow consolidation of the surrounding ground to be accelerated. In a seismic area, they can reduce the ground liquefaction risk.

Inclusions
This technique is designed to provide structural support on all compressible soils. The process permits settlement reduction within acceptable limits.
Inclusions are generally vertical and arranged in a regular grid. They should display deformation and stiffness characteristics appropriate for the surrounding ground and the structures to be supported. Different methods can be used (drilling with or without displacement, driving, vibrating) and different types of fill (ballast, gravel, soil-cement mixing and all types of mortar or concrete) can be used for constructing a superficial foundation system at minimal cost when compared to a deep foundations system.

Download the Platforms and Soil Improvement Brochure

Amélioration des sols Va.pdf


Réalisations

Condamine breakwater

Work : MARITIME WORK | Year : 2001 | Location : MONACO

Consolidation of foundation soil under caisson.

A348.pdf

Palm Jebel Ali Phase 1

Work : PLATFORMS,MARITIME WORK | Year : 2005-2006 | Location : UNITED ARAB EMIRATES

Soil improvement works for the palm-shaped artificial island.

A501.pdf

McDermott Terminal

Work : MARITIME WORK | Year : 2009 | Location : MEXICO

Construction of a terminal for constructing and launching offshore oil platforms

A540.pdf

Storage platform - Montereau

Work : PLATFORMS | Year : 2007 | Location : FRANCE

Trenchmix used as ground treatment in preparation for the construction of a storage platform.

A520.pdf

Patras harbour extension - Phase 1

Work : MARITIME WORK | Year : 2004 | Location : GREECE

Construction of a breakwater and a quay wall made of box caissons.

A535.pdf

Terminal Cuenca del Plata

Work : MARITIME WORK | Year : 2009 | Location : URUGUAY

Constructing an extension to the Cuenca del Plata port terminal as a general contractor

A533.pdf

General Lázaro Cárdenas Refinery - Minatitlan

Work : PLATFORMS | Year : 2005-2007 | Location : MEXICO

Soil improvement and deep foundations works for the construction of an oil refinery.

A508.pdf

Al Raha Beach

Work : MARITIME WORK | Year : 2008 | Location : UNITED ARAB EMIRATES

Diaphragm wall and soil improvement works to create 4 precincts on reclaimed land

A541.pdf


Voyage au coeur de l'ingénierie de pointe

Find out more about our expertise by: