42. Testing of slip-coated piles at Songkhla Port, Thailand

The paper describes the installation and testing of slip-coated pile foundations which were driven to support the concrete quay deck at Songkhla Port, southern Thailand.

The 600mm diameter prestressed concrete piles were manufactured in 20m sections and were spliced into lengths of up to 50 m. Before pile driving commenced the upper layer of recent estuarial deposits in the piling zone were removed and replaced by pumped sand with a maximum depth of 15 m. Below this a thin layer of natural sand was underlain by a 15m thick layer of compressible silts and clays. An irregular sequence of variable sands and stiffer clays provided the support for the piles by end bearing and skin friction. The upper part of the pile was coated with bitumen slip-coat to reduce negative skin friction. Site investigation comprised boreholes and static cone penetration tests on a 20m grid.

Three test piles were driven prior to casting the quay piles and a further three working piles were proof tested. Instrumentation of the static load test piles comprised load and settlement gauges, complemented by rod extensometers in the first three piles. Further dynamic pile testing was carried out during construction. The paper examines the distribution of resistance down the pile shaft and examines the influence of short-term and long-term loading on shaft resistance distribution. A review is also made of the instrumentation and test procedures used for slip-coated piles.

• INTRODUCTION

• GROUND CONDITIONS

• PILE DESIGN

• PILE FABRICATION

• SLIP COAT

• STATIC LOAD TESTS

• DYNAMIC PILE TESTING

• PROOF LOAD TESTING

• CONCLUSIONS

• REFERENCES