Project

Various dredging, reclamation, shore protection and other works intrinsic to the creation of a 400 ha high-end residential island.

Location: West Bay - Doha, Qatar
Client: United Development Company (UDC), Qatar
Period: July 2004 - July 2006
Value: USD/Euro 152 mio

Scope of work

Dredging works
Reclamation works
soft soil improvement
dry blasting
dry rock excavation
on site quarrying for rock
shore protection
concrete works - quay wall

General Information

UDC’s vision behind “The Pearl Qatar” is to bring the atmosphere of the Riviera to the warm waters of the Arabian Gulf. This artificial island in the shape of a string of pearls is designed as a self-sustainable high-end residential area that can accommodate around 30,000 residents. Facilities include villas, apartments, hotels, beaches, shopping malls, restaurants, inland canals and waterways, private and public berths for yachts, etc

Description of the works

D.I. was awarded this highly complex multi-disciplinary project and work started in July 2004.

The project site, a natural shallow area, has subsoil varying from fine materials to very hard limestone. Designed finished onshore elevation levels are +2.5m & +2.7m QNHD and seabed levels are -2.5m & -4.0m QNHD.

Analysis of the soil balance showed that 2/3 of the total reclamation volume needed is to be excavated within the site limits. The remainder is to be borrowed elsewhere by cutter suction dredger. Large pumping distances are bridged using a booster station.

Due to the hardness of certain areas of the subsoil and regardless of the excavation levels, half of the excavation works within the site limits is executed by means of dry excavation and blasting. Areas are bunded and continuous pumping using batteries of 3,000 m³/h pumps allow for working below sea level.

The balance of on-site excavations, the so-called “blue water dredging”, is, depending once again on the hardness of the material, executed by  two shallow water dredgers, the “Al Mahaar” and the “Kalis II”. The CSD “Al Mahaar” was especially re-engineered to allow deployment for rock dredging in extremely shallow areas.

Alternatively there are also areas with unstable silt subsoil that require there levels increased considerably. Here, soft soil improvement techniques are applied using wick-drains and overloading.

The island’s protection against erosion by the sea amounts to approximately 39km of shore protection. 

A vast volume of around 1 million m³ of rock is required. Making work with work, our “rotary Grizzly-installations” and sieving techniques are used on-site to re-use larger quantities of excavated rock for this purpose.

Last but not least some 47,500 m² of quay wall is to be installed. A pre-casting factory is operational on-site to produce some 31,000 pieces of pre-cast elements.

Main Equipment

CSD “Al Mahaar” and CSD “ Kalis II”, inclusive of a booster station and other marine auxiliary equipment
A vast range of dry equipment totaling more then a hundred units ranging from an Liebherr 984C excavator to an agricultural tractor used for compaction purposes
Large 3,000 m³/h dewatering pumps
Rotary “Grizzly” and sieving units
Drilling rigs for dry blasting