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Primrose Hill UTX - Microtunnelling Solution (Guided Augerbore)

HBT was called to site J Murphy & Sons to provide a working solution including full design to allow rising main to pass under the running rails at Primrose Hill & construct pump chamber.

 



HBT devised a microtunnelling solution for a drainage pipe running under rail track in Primrose Hill, North West London. 

The UTX (under track crossing) was designed to encase a new 225mm diameter carrier pipe for managing ground water run-off and preventing rail track flooding.

HBT employed Veda Associates to undertake the full design package this included: - all Network Work liaison following the procedures of F001, F002 & F003.

Working in conjunction with HB Tunnelling & J Murphy to produce a solution to the scheme requirements, following on from several design meetings the final design was produced

 



This not a straight forward UTX as the most challenging aspect was that the reception shaft was sitting on an existing overground rail tunnel. “With barely a metre between the base of the shaft and the tunnel, we had to make sure there was no negative impact on the tunnel. 

 




Working in conjunction with HB Tunnelling & J Murphy to produce a solution to the scheme requirements, following on from several design meetings the final design was produced

Work commenced onsite to install Launch shaft all plant had to be taken into site via road railer

 




In this case, the drive shaft was used to house the drainage pump and the outlet shaft was retained as an access manhole for the drainage system.

The launch shaft was 2100mm diameter concrete ring supplied by FP McCann this had to be excavated deeper to allow pump to work from the chamber at later date.

The caissons were installed using an underpinning method, which was elected to avoid the works impacting the track and trackside infrastructure. Due to the location of the work site within track zone, a technique posing minimum risk of settlement disruption was vital because of the potential to derail trains. 


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Once the launch shaft completed works commence the following weekend to install the micro tunnel under possession, working Friday night through to Sunday afternoon to complete.


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HBT set up rig & construction of the reception pit was being constructed simultaneously.
Once the reception shaft was down the pilot rod entered the shaft, this was checked for line & level prior to proceeding with the 324mm steel sleeve.

Once all checked work commenced on installing the steel sleeve, the rig was removed and transported back out by road railer ready to demobilise from site.

Installation of the rising main took place & grout in place & pumps installed with the launch shaft

Andy Fallon said “Collaboration remained key throughout, working with Peter Ato of Veda Associates & Jamie Rothwell of J Murphy & Son we made a formidable team”

For more information please contact Hugh or Andy on - 0845 388 3325.

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