PORT WORKS DESIGN MANUAL PART 3 Guide To - The University ...

495,5.1 GeneralInstrument monitoring of reclamation provides data for assessing the adequacy of boththe sub-soil and reclamation fill with respect to stability and settlement. This chaptergives general guidance on the planning of instrument monitoring for a reclamationscheme and outlines the functions of some typical monitoring instruments. Methods ofinterpreting monitoring data for stability control during fill placement and verificationof settlement calculated in the design stage are also discussed.5.2 Monitoring InstrumentsInstrument monitoring in a reclamation site is usually concerned with measuring thefollowing three basic parameters at different locations and depths in the reclamation:® Pore water pressure - by piezometers.* Settlement - by settlement plate, extensometers or surface markers.« Lateral deformation - by inclinometers.Techniques for pore water pressure, ground settlement and lateral movement measurementhave improved over the years. Instruments capable of measuring the continuous distributionof vertical and lateral movement with high precision are now available in the market.Reference should be made to the specifications of respective manufacturers for differentmonitoring instruments and specialist advice should be sought where necessary beforespecifying the monitoring instruments in a reclamation project.5.2.1 Pore Water Pressure MeasurementIt is essential to monitor the pore pressures in a drained reclamation to ensure that the excesspore pressure generated by fill placement are in line with predictions, and to confirm that thevertical drains are functioning properly.Pore water pressure is monitored using piezometers. For further details, Chapter 20 ofGeoguide 2 (GCO, 1987) should be referred to. Vibrating wire piezometers are usuallyadopted for monitoring pore pressures in reclamation. These have a rapid response and arerelatively simple to set up.