Pearl Jumeira is an artificial offshore land formation located in Jumeira Beach in the Arabian Gulf and is constructed from Dubai-sourced reclaimed sand and locally sourced rockworks. Reclaimed sand was dredged from known borrow pits in Dubai waters. The island will cover approximately 8.3 million square feet of land (fully serviced with all infrastructure requirements) consisting of more than 3.0 million square feet of residential villa plots and over 90,000 square feet of retail, community, and educational facilities. The current paper presents a geotechnical case study on this reclaimed island in terms of: The geotechnical design, the construction stages, and the ground investigation results. In the geotechnical design stage, soil properties of the reclaimed land were investigated to achieve the design bearing capacity and to assess the risk of liquefaction. In the geotechnical construction stage, soil improvement technologies such as vibro compaction and surface compaction were used. In the soil investigation stage, a set of soil tests were conducted in order to achieve the geotechnical design. These tests include Standard Penetration Test (SPT), Unconfined Compressive Strength Test (UCS), Piezocone Penetration Tests (CPTU), Zone Load Test, Particle Size Distribution (Sieve Analysis), etc.... The thickness of the reclamation fill varies across the site but is typically in the order of 10 m to 15 m and consists primarily of clean sand with lenses of silty materials. The materials below the pre-reclamation seabed comprise of layers of sand and silty materials of varying thicknesses, underlain by the Calcisiltite/Calcarenite bedrock between -10 m and -15 m Dubai Municipality Datum (DMD).

This paper presents a case history of the design, Osterberg load-cell testing, value engineering and revised design by back-analysis of reinforced concrete barrette foundations, resulting in a reduction of barrette length by about 11%, for the 100-storey La Maison tower in Dubai. Rectangular barrettes were selected as an efficient foundation system to transfer 55 MN load per barrette after comparing the design with equivalent-sized circular piles. Bidirectional static load test results were back-analysed using a finite-element model to modify the barrette length. The stiffness parameters were modified after calibrating against the load-cell results, which was matched with a 20% modulus of elasticity from geophysics tests. The relation between unconfined compressive strength and skin friction was back-calculated and compared with commonly used methods in the UAE. Finite-element analysis of a group of barrettes with revised length showed settlement within the limit values. Revising the barrette length by about 11% resulted in significant savings in both cost and construction time.

There is limited published information available on design guidance and performance of deep pile foundations in Dubai, UAE. In response to this situation, the piling industry tends to be over-conservative when designing foundation systems for buildings and infrastructure. Consultants, pile testing experts and the Dubai Creative Clusters Authority decided to collaborate with a common goal: share information with the industry and make pile design recommendations to help colleagues prevent the large-scale over-engineering of pile foundations currently ongoing in the Emirate of Dubai. A total of over 200 pile load test results, from which 91 are preliminary pile load tests, were available to the authors to conduct the study presented in this paper. The interpretation of the available information combined with finite-element back-analyses enabled the authors to propose Dubai-specific relationships between the rock's unconfined compressive strength and the pile's ultimate skin friction resistance. Relationships between the rock's unconfined compressive strength and its elastic modulus are also proposed. Notation c 0 cohesion E rock mass stiffness k 0 coefficient of at-rest earth pressures a side resistance factor b side resistance factor g density s 0 3 max maximum confining pressure s 0 cm global rock mass strength s ci unconfined compressive strength t m measured skin friction t PTP skin friction assumed in PTP design t ult ultimate skin friction f 0 angle of internal friction Cite this article

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