Get the low down from HB Tunnelling

Article: Down Down, Deeper & Down

Working with great clients is always a huge plus to the supply chain of the Construction Industry; when HB Tunnelling were approached, we were only too happy to provide our experience and expertise to develop a range of solutions for the multiple trenchless techniques that would be required on the Ramsgate sewer network improvements scheme.

The improvement scheme is part of a £3 million investment will see a long stretch of wastewater pipe replaced to help protect the environment and ensure wastewater is removed effectively.

HBT where engaged to look at solutions with client to be able to assist in overcoming several hurdles along the proposed route. It was agreed that a 4.5mtr diameter shaft 25mtrs deep & then drive 1200mm diameter from Military road back towards the 4mtrs diameter shaft would be the best & most cost effective solution to transfer the new 600mm pipeline from the high level cliff down to the beach.

HB Tunnelling mobilised to site & commenced works with the excavation of the 4.5mtr diameter shaft, the ground condition of dry firm chalk was ideal for the installation.

(Last segment ready to be installed)

The 4.5 diameter shaft was completed ahead of programme. Works then commenced of excavating a launch shaft for the 1200mm pipejack which was located down on Military road. Due to the nature of the works involved & the impact that this would have on the local residents; MGjv & Southern Water public relation teams work in conjunction with the local community & Thanet District Council to ensure that the local community had a voice and we would listen to all concerns. This was undertaken in Two drop-in sessions held by MGJV inviting residents to a questions and answers session also during the works Five letter drops was made updating the immediate residents on progress. The one concern was the grass land area at government way, which is located along the promenade this is where the 4.5mtr diameter shaft is located.

Local residents & Thanet District Council was concerned that the grassed area would not be reinstated in time for summer time & the area looking desert like & unsightly. As a team we looked how we could mitigate the grassland area becoming damaged, it was then that we opted to reduce the size of the compound area & relocate the spoil lay down area further down the promenade, thus meaning that the spoil being double handle to another compound with the use of tracked dumpers, this reduced the damage to grassland area from 100% down to just 15%

All spoil from the works was being transported & used to raise the flood level at a local housing development and to extend the local golf course.

Traffic management was undertaken at Military Road thus closing the lanes around the roundabout at the port to allow safe construction of the launch shaft.

Launch shaft completed & ready to install the EX1200 pipejacking machine

Works commenced on the installation of 1200mm diameter concrete jacking
towards the 4.5mtr diameter shaft.

During the works, the fire service became very interested with the deep shaft works and wanted the opportunity to undertake rescue exercise from the shaft; they approached us to see if we could give them weekend possession of the 4.5mtr diameter 25mtr deep shaft for their training exercise.

Once the MGJV & Southern Water approved the training exercise they free to use at the weekend.

Firefighters used a newly-built, 25m-deep shaft, the equivalent height of a nine storey building, on Ramsgate’s cliff top to test their rescue skills.

The mock rescue mirrored scenarios such as mine shaft or sinkhole falls and cliff incidents. For the exercise, a dummy was used to represent an injured person who had fallen down the hole. Local crews from Ramsgate abseiled down the shaft to treat the casualty. The Kent Fire and Rescue Service line rescue team then set up their specialist rescue gear to bring them back up to safety

Dave Hudson, KFRS Watch Manager, was one of the fire-fighters to abseil down the shaft to treat the casualty. He said: "We often deal with line rescue situations, but this was an extraordinary opportunity to hone our skills. To put the depth of the shaft into perspective, it was the equivalent of abseiling down the side of a nine-storey block of flats.

"Crews are confronted with a huge range of emergencies and it is important that we regularly practice techniques in order to be ready for every eventuality.

"We are very grateful to Southern Water and its construction partner MGjv & HBT for giving us the chance to use the shaft for our exercise."

Southern Water Project Manager Andy Arnold said: "We were pleased to assist our local firefighters by letting them use the shaft for their exercise. Partnership working is important to us and this was an unusual opportunity for them to practice skills that was too good to miss."

Once the Kent Fire & Rescue had completed their training it was back to work to install 600mm pipe with the 1200mm pipejack, the pipe was prepared and spiders where fitted to the 600mm pipe to ensure that it stayed centrally within the 1200mm pipe.

Installation of product pipe 600 mm diameter undertaken by sliplining technique.

Ewald MGjv Site Manager commented “HB Tunnelling have been very helpful and flexible when it came to scope changes. Works were carried out as per the programme with regular check-ins by senior management Hugh & Andy this giving the job a personal touch, No complaints and 6 commendations received from local residents”

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

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