PROJECT OVERVIEW.
Pipejack and Freebore
Both pipejacking and freeboring techniques were used depending on the ground conditions. The ground conditions varied from saturated clay (N=5) to Hawkesbury Sandstone UCS=50MPa. Pezzimenti Tunnelbore completed works by directly for Lend Lease managing the construction of the shafts as well as working as a specialist subcontractor for Diona P/L which was a major contractor.
Microtunnel into a Manhole.
Of note was a Ø800 core drill into the collecting MH of a live sewerage pump station. The collecting MH is 12m deep and there was concern that excavation around the manhole for a standard connection would weaken the structure. Pezzimenti Tunnelbore proposed a solution based on previous works to core into the structure from a jacking shaft some 20m away. The coring process minimised vibration during the cut-in.
Site set-up inside an 11m deep shaft to microtunnel 52m x 1130mm diameter microtunnel, pipejacking a 900 diameter J-series RCJP.
900mm diameter J-Series Reinforced Concrete Pipes pipejacked beneath the railway.
Operator monitors the equipment as Pipejacking beneath the railway commences. Looking down into the shaft at Work Lot 6.
Microtunneling was utilised at work lot 20 to preserve environmental areas including those with Aboriginal Significance, beneath a creek and below a rocky outcrop.
Down the shaft at Work Lot 20, Pipejacking commences. This 15m microtunnel would cross beneath a creek bed.
MICROTUNNEL 1.
Pipe in a Pipe by Pipejack Method
Length. 203m
Diameter. 530mm
Ground. Clayey Sand
Casing. 508 Steel
Carrier. 300 GRP
Grade. 0.30%
MICROTUNNEL 2.
Pipe in a Pipe by Pipejack Method
Length. 180m
Diameter. 530mm
Ground. Clayey Sand
Casing. 508 Steel
Carrier. 300 GRP
Grade. 0.30%
MICROTUNNEL 3.
Pipe in a Pipe by Pipejack Method
Length. 156m
Diameter. 530mm
Ground. Clayey Sand
Casing. 610 Steel
Carrier. 400 GRP
Grade. 0.45%
MICROTUNNEL 4.
Pipe in a Pipe by Pipejack Method
Length. 155m
Diameter. 630mm
Ground. Clayey Sand
Casing. 610 Steel
Carrier. 400 GRP
Grade. 0.45%
MICROTUNNEL 5.
Pipe in a Pipe by Pipejack Method
Length. 162m
Diameter. 630mm
Ground. Clayey Sand
Casing. 610 Steel
Carrier. 400 GRP
Grade. 0.45%
MICROTUNNEL 6.
Free Pipe by Freebore Method
Length. 52m
Diameter. 560mm
Ground. Sandstone
Casing. None
Carrier. 450 SN10K GRP
Grade. 0.5%
MICROTUNNEL 7.
Pipe in a Pipe by Pipejack Method
Length. 15m
Diameter. 780mm
Ground. Sat. Alluvials
Casing. 762 Steel
Carrier. SN20K GRP
Grade. –0.4%
MICROTUNNEL 8.
Free Pipe by Freebore Method
Length. 145m
Diameter. 700mm
Ground. Sandstone
Casing. None
Carrier. 525 SN20K GRP
Grade. 0.4%
MICROTUNNEL 9.
Free Pipe by Freebore Method
Length. 20m
Diameter. 815mm
Ground. Sandstone
Casing. 800 Steel
Carrier. 525 SN20K GRP
Grade. –0.4%
MICROTUNNEL 5.
Pipe in a Pipe by Pipejack Method
Length. 52m
Diameter. 1130mm
Ground. Shale
Casing. 900 J RC
Carrier. 800 PE
Grade. 14.1%
