Highways Agency

What will the tunnel look like?

What will the tunnel look like?

Welcome to issue four of the Hindhead news. This is the first edition of the Hindhead News with input from the full A3 team and to reflect this we have altered the layout and design of the newsletter.

Keeping you informed about progress on the A3 Hindhead scheme

Partnering

Team members from Atkins (the Highways Agency's representative), Balfour Beatty (Contractor) and Mott MacDonald (Designer) are now all working together in Epsom, and are regularly visited by representatives of the Highways Agency and A3 project specialists, such as the members of the environmental team. Partnering and working together will play an important part in the development of the scheme, and is an intrinsic part of the way the Highways Agency's Early Contractor Involvement schemes are run.

Tunnel Closure

This edition of the Hindhead News focuses on the issues surrounding the closure of the old A3 once the tunnel is in use. We have concentrated on this aspect of the scheme because we are well aware of the local concerns being raised about the closure. We have set out to address those concerns with articles relating specifically to the A3 closure, including traffic impacts, safety issues and facts about the tunnel.  We have also included an article about the work involved in the ground investigations, and an update on current progress.

Communication

In addition to communicating with the local community through this newsletter, we are continuing face to face meetings with various interested parties.

This includes local residents who live near to the proposed scheme. By meeting the residents individually we are able to answer their questions, take on board any good ideas, and hopefully allay any concerns they may have about the scheme. Visits have started at properties near the southern end of the scheme, and we hope to eventually contact all residents living in close proximity to the proposed scheme.

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Old A3 closure and tunnel opening are intrinsically linked

by Paul Arnold
Highways Agency's project team leader

The considerable benefits of the A3 Hindhead tunnel scheme are intrinsically linked to the closure of the existing road around the Devil's Punch Bowl to through traffic. This is the conclusion of a study carried out by the Highways Agency's A3 Hindhead Team.

The tunnel scheme will remove the major bottleneck of the A3/A287 traffic signals and so relieve Hindhead of its daily congestion, and the surrounding country lanes of rat-running traffic. This will benefit Hindhead and the highly prized surrounding countryside, bringing a safer, more pleasant tranquil environment for the people of Hindhead and visitors to the area. At the same time drivers on the A3 will have safer and more reliable journeys.

Statutory Protection

The construction of the tunnel and the closure of the A3 demonstrate the Government's commitment to ensuring that transport schemes do not damage important habitats, species and landscapes.

The importance of the area around Hindhead is borne out by the following special designations:

• the environment around Hindhead was declared an Area of Outstanding Natural Beauty in 1958;
• based on Advice from English Nature, the Government has also declared the Devil's Punch Bowl a Site of Special Scientific Interest (SSSI) for its flora and fauna;
• under the EU Directive on the conservation of wild birds, it is declared a Special Protection Area.

Environmental benefits of closure

Closing the existing A3 between the National Trust Café and Boundless Road to through traffic after the tunnel is built will bring the major environmental benefits of:

• reuniting the severed parts of the SSSI providing the flora and fauna with an environment free from air, noise and water pollution caused by traffic on the old A3;
• restoring the peace and tranquillity of the area allowing people to enjoy the magnificent scenery in safety;
• compensating for the significant environmental impacts on Tyndalls Wood and Boundless Copse.

The essential support from the organisations with statutory duties to protect this special countryside are conditional on the existing A3 being closed. The tunnel and the closure of the A3 are seen as an indivisible package.

Answering concerns

The A3 Hindhead Team set out to answer some of the questions raised by those who were concerned that closing the existing A3 would bring unwanted traffic changes to local communities and reduce safe options for diversion routes in the event of a tunnel closures.

Traffic forecasts

New opening year traffic forecasts were prepared using sophisticated computer modelling techniques with up to date traffic counts in the local area.

Key conclusions were that:

• around 4700 vehicles a day would use the old A3 if it remained open after the scheme was built;
• the same amount of traffic would pass through Grayshott whether the old A3 remained open or closed;
• traffic calming and junction layout have more impact on local traffic flows than if the old A3 is open or closed.

Accident risk study

The study also looked at the accidents that could occur if the old A3 was kept open compared to it being closed using three different scenarios. These were: normal traffic conditions; planned closures of one of the tunnel bores for maintenance; and closure of the tunnel in the event of an accident.

The study found that:

• in normal operation closing the existing A3 would be the safer option;
• closures due to accidents on the new A3 would be reduced to a third of the present frequency, and then only affecting traffic in one direction;
• during planned closures the A3, using one bore of the tunnel in contraflow, would be nearly twice as safe compared to using the existing A3;
• although closing the existing A3 would increase the accident risk during unplanned closures due to longer diversion onto other routes, these would be of a relatively short duration;
• overall there would be on average fewer accidents a year if the existing A3 was closed.

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Conclusions

By building the Hindhead tunnel scheme and closing the old A3 to through traffic the Highways Agency would be fulfilling its commitments to safer roads and more reliable journeys and its obligation to mitigate the impact of road schemes on protected environments. There would be benefits to the natural and built environment, enabling people to enjoy this special area to the full and in safety, while providing the opportunity for the regeneration of Hindhead village freed from the blight of the present traffic.

Peak hour two-way traffic flow

The tables below list the modelled traffic flows for key roads in the study area for the different scenarios which were tested. The forecasts in the tables differ from those shown in Newsletter No 2 because they are based on more detailed modelling of local traffic using the actual peak hours.

Case 1

Old A3 closed across Hindhead Common

Case 2

Old A3 open across Hindhead Common

Case 3

Old A3 closed across Hindhead Common, Woolmer Hill Rd traffic calmed, left turns out and right turns in at existing A3-Crossways Rd junction banned

Case 4

Old A3 open across Hindhead Common, Woolmer Hill Rd traffic calmed, left turns out and right turns in at existing A3-Crossways Rd junction banned

Morning Peak Hour	Year 2002	Year 2009	Year 2009 (with the scheme)
	(without the scheme)	(without the scheme)	Case 1	Case 2	Case 3	Case 4
Old A3 across Common	2110	2340	0	340	0	450
New A3 in tunnel	N/A	N/A	3340	3060	3310	2940
B2131 Liphook Rd	990	1230	1130	1140	1230	1220
A286 Grayswood Rd	1050	1220	980	940	980	940
Thursley Rd	350	670	310	310	320	310
A325 south of Bordon	1040	1400	1160	1160	1150	1150
A325 north of Bordon	1730	1760	1860	1860	1870	1860
A287 Churt Rd	610	900	980	1020	960	1010
A287 Hindhead Rd	800	910	1180	1340	1190	1370
Headley Rd west of Crossways Rd	910	870	1010	1010	900	960
Whitmore Vale Rd	100	150	130	130	130	130
Headley Rd east of Crossways Rd	690	460	620	650	750	840
Crossways Rd	430	540	640	580	450	410
Woolmer Hill Rd	430	480	550	500	320	300
Nutcombe Lane	210	350	20	20	90	70
High Pitfold	150	140	20	20	90	70
Old A3 north of Headley Rd	2150	2200	1110	990	1250	1120
Old A3 south of Crossways Rd	1860	2210	520	460	570	520

 

Evening Peak Hour	Year 2002	Year 2009	Year 2009 (with the scheme)
	(without the scheme)	(without the scheme)	Case 1	Case 2	Case 3	Case 4
Old A3 across Common	2090	2430	0	390	0	390
New A3 in tunnel	0	0	3030	2670	3020	2660
B2131 Liphook Rd	730	950	920	920	960	960
A286 Grayswood Rd	1050	1270	1220	1210	1220	1210
Thursley Rd	140	380	170	160	170	160
A325 south of Bordon	940	1430	1250	1240	1230	1230
A325 north of Bordon	1710	2040	1940	1940	1940	1950
A287 Churt Rd	540	770	850	860	860	860
A287 Hindhead Rd	1010	1210	1240	1330	1280	1340
Headley Rd west of Crossways Rd	590	600	800	800	760	770
Whitmore Vale Rd	10	20	10	10	10	10
Headley Rd east of Crossways Rd	410	460	550	600	670	700
Crossways Rd	390	450	400	310	320	300
Woolmer Hill Rd	230	290	400	360	290	280
Nutcombe Lane	120	160	70	70	70	70
High Pitfold	120	160	60	70	70	70
Old A3 north of Headley Rd	2150	2350	1070	770	1090	780
Old A3 south of Crossways Rd	2000	2290	300	300	390	360

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A3 tunnel Frequently asked questions

How long is the tunnel?

About 1.9km (1.2 miles).

How deep is the tunnel?

Depth will vary between 20m to 60m.

Will there be one or two tunnels?

There will be one tunnel for each direction of travel.

How big will the tunnels be?

Each tunnel will incorporate a 7.3m wide 2 lane carriageway with a minimum 1.2m wide verge on each side.

Are the tunnels linked?

They will be connected by cross passages at 100m intervals.

Will there be a services tunnel between the two main bores?

No, we do not need to provide a separate tunnel to accommodate services.

What happens if the electricity supply fails or the ventilation fans break down?

Under normal operating conditions, the movement of traffic would be sufficient to ventilate the tunnel. There will be backup power supplies, and the ventilation system is designed to operate successfully without all fans running.

Will any road users be banned from the tunnel?

Yes, in the interest of safety, cyclists, pedestrians and equestrians will be diverted around the tunnel along the route of the old A3.

What is unique about this tunnel project?

It will be the longest non-estuarial crossing tunnel in England, except for the proposed A303 tunnel at Stonehenge.

How will the tunnels be constructed?

They will be constructed using the sprayed concrete lining (SCL) method.

What does SCL involve?

SCL involves excavating the tunnel in There small sections and applying a primary sprayed concrete shell to support the ground. A waterproofing membrane is then installed followed by a cast concrete lining to complete the spoil tunnel structure.

Are these tried and tested techniques, or are you trying them out for the first time? Where have similar road tunnels been built in the UK?

The sprayed concrete lining (SCL) technique is tried and tested and has been used in many tunnels elsewhere in the UK and the world. Tunnels constructed in the UK using similar techniques exist at Roundhill on the A20 and at Southwick on the A27.

How much earth will be excavated from the tunnels and what will you do with it?

There will be around 300,000 cubic metres of spoil generated which will be used to build the highway embankments on the northern side of the tunnel. No spoil will be taken off site.

Will there be any settlement above the tunnel?

Initial calculations predict extremely small settlement will occur; however we will monitor this during all tunnelling operations.

What safety features are you incorporating into the design?

The key to ensuring we have a safe tunnel design will be:

• High quality lighting and ventilation
• Continuous traffic monitoring and CCTV surveillance
• Early automatic detection of vehicle breakdowns, accidents and fires
• Quick appropriate information to drivers using automatic variable message signing, radio interrupt systems and loudspeakers
• Well equipped emergency points with fire extinguishers, a manual call button and emergency telephones that can be used by disabled persons
• Easily identifiable safe escape routes
• Ensuring emergency vehicles can get to the tunnel quickly
• Re-routeing traffic away from the tunnel if blocked by an incident
• Detailed risk assessment of all credible hazards
• Planning of incident management

We will be looking in detail at these issues over the next twelve months in conjunction with the Tunnel Design and Safety Consultative Group comprising representatives of emergency services, local authorities and the Environment Agency.

When will you start building the tunnel and how long will it take?

The start date for construction depends upon a successful Public Inquiry. The current best estimate is a start of construction in early 2005, with tunnel construction starting in 2006 and finishing mid 2008. The fitting out of the tunnel will take another year, and opening is forecast for mid 2009.

Why does it take so long?

It takes so long because our construction programme is designed to reduce disruption locally. For example, to minimise the effect on the majority of residents, we are planning to construct the tunnels from the northern end. This will enable us to move the large amounts of spoil through the tunnels from the south to the north to avoid disrupting the local road network. Once the tunnels are built it is essential that we take sufficient time to install, commission, integrate and test the safety critical systems of the tunnel.

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Ground investigations... in the snow

The A3 Team are carrying out further investigations to gain a fuller understanding of the ground conditions. The investigations comprise the drilling of 27 boreholes up to 80m in depth, and 25 trial pits.

The investigations will allow the designers to fine tune the tunnel route alignment and will provide sufficient geotechnical and groundwater information for the design of the tunnel and its portals.

Existing information suggests that the shape of the Devil's Punch Bowl, the largest spring sapped valley in Europe, is likely to be controlled by planes of weakness - faults - within the rocks. Up to now there has been very little exploratory work carried out within the Punch Bowl itself, so it is important to investigate there. Detailed discussions were held with the National Trust and English Nature to find the least damaging way of doing this, which was to use a large mobile crane parked on the A3 to lift a drilling rig in and out of position during night-time carriageway closures.

The tunnel route generally runs within the Hythe beds, which are mainly formed of layers of sands and sandstones which can be highly variable in their nature. Underlying the Hythe beds is the Atherfield clay. The top of the Atherfield clay is marked by a spring-line which can be seen in the Devil's Punch Bowl and within the Boundless Copse areas. Bore holes at the top of Hindhead Common will encounter the full thickness of the Hythe Beds while those within Boundless Copse will encounter the Atherfield Clay near the surface.

The exploratory holes have been carefully sited to provide a three-dimensional picture of ground conditions. Groundwater monitoring equipment will be installed togive a better understanding of the groundwater levels and movements, how they vary seasonally, and how they relate to the present spring-lines.

The work has been timed to avoid disturbance to ground nesting birds within the Site of Special Scientific Interest (SSSI) and the Special Protection Area (SPA), particularly within the environmentally sensitive lowland heath habitat of Hindhead Common. All exploratory holes have been located to cause minimal environmental impact. Agreements with landowners regarding locations, access, and working practices were agreed beforehand. An ecologist closely monitors the work to ensure that no protected species are disturbed or harmed.

Drilling works are currently continuing - come rain or snow - in order to achieve the programmed fieldwork completion date of early May.

The work has been timed to avoid disturbance to ground nesting birds within the Site of Special Scientific Interest and the Special Protection Area.

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Land surveys

The latest survey data is now being collected and collated by our land survey team.

During the development of the scheme over the past decade a number of surveys have been carried out. To ensure the accuracy of this previous data, our surveyors are verifying the existing survey network and the three-dimensional ground level model, as well as establishing additional survey control stations to facilitate subsequent surveying requirements.

The team is now working to establish the exact location of specific trees that have been identified during the vegetation survey, and setting out centrelines for the tunnel approaches.

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Ecological surveys

Most of our ecological survey work will be carried out during the spring and summer, so only a small number of surveys are being carried out at present.

But some are well underway, including surveys of wintering birds, assessing deer movements in the portal areas, and a review of bat roost locations.

Surveys due to start include those for invertebrates, great crested newts, breeding birds, badgers and reptiles.

Proposed borehole locations in ecologically sensitive areas have been visited by an ecologist, and every effort is made to ensure that any environmental damage is limited. All work in the SSSI has been approved by English Nature.

Consultation with interested parties has also started on how best to protect deer and reptiles along the line of the route.

Our targets for the next 3 months

• Complete preliminary consultation with residents, landowners and other stakeholders
• Complete ground investigation works
• Prepare indicative scheme layout drawings
• Finalise indicative scheme design
• Prepare draft Environmental Statement
• Prepare draft orders, plans and schedules
• Plan a pre-draft orders exhibition for July

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Contacts

We welcome feedback. If you would like to express views regarding this publication or about any aspect of the A3 project, including ongoing works or future plans, please see the following contact details.

For operational matters please contact the A3 Hindhead team in Epsom, and approach the Highways Agency in Dorking on policy and procedural issues.

Every effort is made to respond within one week.

By post

Paul Hoyland Contract Manager
A3 Hindhead Team
Sir William Atkins House, Ashley Avenue
Epsom, Surrey KT18 5AL

Paul Arnold Highways Agency, Operations
Directorate SE
Room 2C, Federated House
London Road, Dorking, Surrey RH4 1SZ

By e-mail

A3 Hindhead Team:
a3.hindhead@bbcel.co.uk
Highways Agency:
a3hindhead@highways.gsi.gov.uk

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