Memorial Park Alliance Ph: 0800 020 086 Email: [email protected] www.nzta.govt.nz/memorial-park Our contact details Why use sheet piles? Most areas on site are not particularly sensitive to lowering ground water levels. The excavation in these areas will be retained with horizontal timber poles lodged between steel posts (referred to as king posts). Sheet Pile Installation 1 The ground between the Carillon and the Tasman Gardens Apartments is sensitive to settlement through loss of ground water pressure, so in this area sheet piles will be used. Interlocking steel sheets (sheet piles) form a barrier to ground water loss. The sheet piles will be installed prior to excavation for construction of the underpass. Installing sheet piles In developing the plan for installing the sheet piles we have considered many issues including: • The presence of underground services such as water, electricity and sewers • Ground water levels outside the excavation • Noise and vibration effects upon people and buildings • Vibration effects upon the old Tory St Sewer • Disruption to pedestrian and vehicle traffic flow
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Memorial Park Alliance
Ph: 0800 020 086Email: [email protected]/memorial-park
Our contact details
Why use sheet piles?Most areas on site are not particularly sensitive to lowering ground water levels. The excavation in these areas will be retained with horizontal timber poles lodged between steel posts (referred to as king posts).
Sheet Pile Installation 1
The ground between the Carillon and the Tasman Gardens Apartments is sensitive to settlement through loss of ground water pressure, so in this area sheet piles will be used. Interlocking steel sheets (sheet piles) form a barrier to ground water loss. The sheet piles will be installed prior to excavation for construction of the underpass.
Installing sheet pilesIn developing the plan for installing the sheet piles we have considered many issues including:
• Thepresenceofunderground services such as water, electricity and sewers
• Groundwaterlevelsoutside the excavation
• Noiseandvibrationeffects upon people and buildings
• Vibrationeffectsupontheold Tory St Sewer
• Disruptiontopedestrianand vehicle traffic flow
Memorial Park Alliance
Ph: 0800 020 086Email: [email protected]/memorial-park
Our contact details
Method
Sheet Pile Installation 2
A-frame sheet pile guide
• Firstundergroundservicesaredivertedfromthepathoftheretaining wall.
• Trialsdeterminethebestmachineryforinstallingthesheetsin the ground; noise levels and vibration levels are measured and assessed in order to establish the best methodology.
• Holeswillbedrilledto12mdepthforeveryalternatesheetinstalled (this will reduce the amount of noise and vibration during installation).
• AnA-framepileguidewillbeplacedabovetheholestoguide the sheets into position and keep them vertical. The A-frameis8mlong,4mhighandspans2meithersideofthe sheet wall.
• Thewallwillbeplacedin6mlongsections.Eachsectionwillbepartiallydrivenintotheground-commencingattheCarillon end of the site. These sheets will be left sticking 5m aboveground,justabovetheA-framepileguide.
• Thepileguideandfirstcranewillthenbemovedalongtostart the next 6m section of wall.
• Asecondcranewilldrivethefirstsectionofsheetsallthewayintotheground-usingateamoftwocraneswillreducethe overall time it takes to install the wall.
• Thecompletedlengthofthewallwillbe90m.
Working around the sewer• Thesheetwallwillbe40mlongbeforeitreachestheToryStreet
Interceptor Sewer.
• Thesewerisanegg-shapedbrickstructurewhichismorethan100yearsoldandis8mbelowground.
• Monitoringequipmentwillbeinstalledinthesewermanholetomeasure any effects on the sewer.
Memorial Park Alliance
Ph: 0800 020 086Email: [email protected]/memorial-park
Our contact details
Traffic management• TrafficmanagementwillisolatetrafficandpedestriansfromtheA-framesheetpilingoperation.
• Thepicturebelowindicatesthatthereissufficientroomforanarticulatedtrucktopassbytheworksundersupervision.
• TrafficwillbecontrolledmanuallywithStop/Goboardsduringthedayandsignsorsignalsatnight.
Sheet Pile Installation 3
Noise and vibration monitoring• Noiseandvibrationmonitoringwillbecarriedout
from the start of the work. This will keep the team informed and allow review of methods if guideline limits are in danger of being breached.
• Onceasectionofsheetsisatfinaldepth,theholeswillbebackfilledwithamixtureofstoneand cement grout.
• Groundwaterlevelsoutsidetheexcavatedareawill be monitored during the work. A drop in levels willbequicklyaddressedbytoppingupthestonefilledholeswithwater.
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