HSE launches Tesco tunnel collapse probe

The Health & Safety Executive (HSE) has revealed that it is to look into two possible causes for the partial collapse of the Tesco rail tunnel at Gerrards Cross, Buckinghamshire.

The two are the quality of infilling works surrounding the tunnel carried out by Amersham-based subcontractor Clark Contracting and the standards of the structure’s design, undertaken by RECO, which was signed off by third party checker Atkins.

Allan Spence, the HSE inspector leading the investigation, told CJ: “Our main focus of attention is on the pattern of the infill used on the outside of the tunnel’s concrete segments. It is this infill that will give the tunnel its strength, but can also provide a weakness depending on the quality of the works.

“We are also waiting for designer RECO to go through the drawings for the tunnel, which might reveal more. From what we can see, there is nothing unique about the tunnel’s design.”
He added that the investigation would involve looking in detail at Jackson’s method statement and the records kept by its subcontractors over what type of compacting was carried out on the infill.

Although it was too early to say who was at fault for the collapse, Spence said the HSE would be in a position to prosecute if it felt that inadequate steps had been taken to ensure the safety of workers and members of the public.

Clark Contracting was unwilling to comment as CJ went to press.

But Jackson Civil Engineering has launched its own detailed investigation down its supply chain into the collapse .

Jackson’s chief executive Richard Neall said: “We will sit down and work with our project team to try and determine what happened. There will be no stone left unturned.”

Neall was unable to estimate how much the clearance work would cost, but added that compensation payments to Network Rail (NR) for the disruption to its services would be around £5m to £10m.

NR said it would not reopen the line until the tunnel has been signed off as safe by the HSE, which could be “several weeks”.

A total of 10,000t of spoil has been cleared from the floor of the tunnel and 45 concrete arches, damaged from a first tunnel cave-in and a second smaller collapse, have now been removed.