Abstract:
The geology and karstic nature of the Kuala Lumpur (Malaysia) limestone are described in relation to pile foundation problems of heavily loaded structures. The presence of cavities, pinnacles, cantilever slabs, floating slabs and pockets of soft silty clay and loose sand in the underlying limestone bedrock presents formidable challenges to foundation engineers. Other problems include insufficient seating and damage to pile tips due to irregular and sloping bedrock surfaces. There is also the added difficulty of detecting the location and extent of cavities. Empirical design methods and local construction techniques have been successfully used such as: (i) bridging limestone cavities and slabs by filling with concrete, (ii) utilizing numerous small diameter high yield stress piles to distribute the loads and to withstand high driving stresses, (iii) filling cavities with concrete, and (iv) using micropiles to redistribute the loads. Two case histories are presented, consisting of an access ramp and a tall building. In each of these case histories, the soil investigation methods, the pile bearing capacity calculations, the selection of pile types, the pile load tests, the pile driving criteria, and construction problems are outlined and discussed. The pile foundation used consisted of H-section, high yield stress, 355 x 368 mm, driven steel piles with capacities of 750 kN to 1280 kN for the access ramp structures and the same H-section steel piles with pile capacities of 965 kN to 1070 kN for the tall building