Ground Improvement for Liquefaction Mitigation of Sand Deposits in Southern Dubai

Abstract

AbstractThe present study involves the case study of the geotechnical investigation carried out in the commercial area of Jebel Ali region in southern Dubai, United Arab Emirates. The place is a coastal city and a commercial hub with many infrastructural developments. As a part of an expansion project, it was proposed to construct a double-span steel portal building, a steel drum factory, and 100 m high tower, with a superimposed load of 35 kN/m2 and column loads varying from 200 to 700 kN. Nearly 14 boreholes were drilled with varying depths from 10 to 50 m maximum and 24 static cone penetration tests with pore water pressure measurements were performed to ascertain the sub-surface profile. The undisturbed and disturbed soils were also collected for further laboratory analysis. The soil investigation program revealed fine silt as the upper soil layers and medium dense silty sand and calcareous sandstone prevailing at larger depths. Shallow foundations were recommended for the proposed structures. Isolated strip footings for the auxiliary structures, raft foundations for the tall tower, and drilled pile foundations for every main structure were recommended. However, the upper fill soil is loose and highly susceptible to liquefaction effects, which include, loss of bearing strength, surface settlement, negative skin friction on piles, and uplift pressures on the lightweight structures. The region is also grouped under zone 2A with the seismic zone factor (Z) of 0.15. The phenomenon of liquefaction can cause large total and differential settlements, hence ground replacement with the stone column is recommended. Stone columns of diameter 500 mm and length 3 m were adopted to densify the upper soil fill. A total of 1621 stone columns were installed in a rectangular grid pattern with 1.50 m c/c. The overall increase in the bearing capacity and the improvement is verified through a number of cone penetration tests, plate load tests, and zone load tests.KeywordsLiquefactionStone columnCone penetrationBearing strength