Project Scope

The project scope consisted of completing geotechnical borings over water for field testing and soil sampling needed to design of the proposed cruise ship pier

Geotechnical Laboratory Testing

moisture contents, index testing, sieve analysis, soil classification tests, rock core compressive strength tests, direct shear on soils, CU triaxial tests with pore water pressure measurements, organic content, consolidation tests.

Drilling and In Situ and Field Testing

Field work consisted of over twenty (20) over water test borings with SPT and undisturbed (Shelby tube) sampling and HQ size rock coring. Boring depths ranged between 120 ft to 130 ft below water level.

Challenges

Over water geotechnical drilling including rock
coring and undisturbed samples allows for minimal movement, since it could affect sample quality and damage drilling tools. The project was performed from 140 ft length, 30 ft width spud barge. The borings were proposed in areas having water depths ranging from 25 to 45 ft beneath water level. Ground swells from atmospheric systems in the Caribbean produced slight vertical displacements of the barge.

Solutions

Using knowledge gained from marine projects in the Caribbean region, our team employed customized spring subs and flexible base supports to improve sampling quality by reduction of displacement effects. The team’s experience drillers and supervising engineering staff employed techniques such as controlling rotation speeds, water pressures and using bio degradable polymers to improve sampling. These field procedures resulted on the effect that the team was able to core recover, weak rocks, hard clays, closely fractured rock with weathered rock joints and intact strong rocks with recoveries over 95 % with most being near 100%.