IADC Publishes ‘Facts About’ Soil Improvement

The International Association of Dredging Contractors (IADC) has just published a new ‘Facts About’ publication on soil improvement.

‘Facts About’ is a series of concise, easy-to-read leaflets which give an effective overview of essential facts about specific dredging and maritime construction subjects.

Each leaflet provides a kind of ‘management summary’ for stakeholders who need a quick understanding of a particular issue.

The leaflets are part of IADC’s on-going effort to support clients, consultants and others in understanding the fundamental principles of dredging and maritime construction because providing effective information to all involved parties is an essential element in achieving a successful dredging project.

What is soil improvement?

In the dredging industry soil improvement is typically implemented to:

• prevent excessive settlement of reclaimed land when it is being used for construction purposes (roads, airports, bridge and other foundations);
• enhance the soil stiffness and density to prevent liquefaction which can lead to damage to structures in earthquake sensitive regions;
• improve the shear strength of the soil to prevent slip failure and increase the bearing capacity of the soil;
• immobilize or stabilize contaminants in dredged soil in order to mitigate and preferably eliminate environmental impacts.

Soil improvement techniques vary depending on the characteristics of the soils and sub soils. Some techniques are applied to consolidate existing loose sub soils and some are specifically for compaction of newly reclaimed soil.

Why is soil improvement important?

Typically, potential reclamation sites are shallow coastal zones or marshy lowlands. The soil in these areas often consists of thick layers of soft clay or silts.

Reclamation work increases the load on these soft layers, causing widespread settling.

Waiting for the natural settlement of this land is time consuming and thus costly and may put a project in jeopardy if it cannot be accomplished in a designated period of time.

To accelerate the settlement process, dredging contractors have developed specialized solutions to consolidate these soft soils. In addition, newly reclaimed soil is often in a loose state and may not meet the demands of the planned infrastructure and therefore needs to be improved.

Facts About Soil Improvement