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

33(2) Detailed Stability AnalysisThe detailed stability analysis method for checking the stability at each interim constructionstage is covered in Section 3.1.3.(3) UseofGeotextileWhere used, geotextile is normally laid on the seabed before reclamation fill is placed. Itprovides separation between the fill and the underlying marine mud preventing the punchingof the fill into the seabed and helps to prevent the creation of mud waves. However, thebenefits of the geotextile may be negated by improper overlapping or inadequate seaming atthe joints. Close site supervision and careful inspection after laying is required to ensure theproper functioning of the geotextile.(4) MonitoringMonitoring by means of instrumentation plays an important role in detecting potential failureduring filling. The instrumentation data collected on site can be used to estimate thesettlement, lateral deformation and pore water pressure change of the underlying marine mud,alluvial clays and silts. Details are covered in Chapter 5 of this part of the Manual.(5) Miscellaneous ConsiderationsThe following should also be considered:* Site history - Pre-construction site investigation should be well planned andexecuted to provide up-to-date and sufficient information for the proper designof the reclamation. During the site investigation, if there are unusualirregularities in the seabed topography or subsoil layers, the designer mustdetermine whether these are signs of distress caused by past works. If there isevidence that the marine mud in the site has been disturbed before, tests todetermine the remoulded strength must be carried out. The remoulded shearstrength is more appropriate for stability analysis in this situation. Thedisturbed mud profile should also be used in the analysis.• Reclamation sequence - Fill should not be placed until seabed preparationworks have been completed, to the extent that fill deposition will not adverselyaffect the stability. Preparation works include laying of geotextile where