Introduction

Welcome to the HS2/ALIGN information sharing event for the Future Engagement Vent Shaft. Early next year we will hold an event asking for your views and ideas At this event we would like to: on the design of the vent shaft headhouse. Then, after we have taken • Share with you some of our early work on the design of the vent your feedback into account and worked further on the design, we shaft and headhouse will hold a follow up event. Both of these events will have further • Explain the construction process for building a vent shaft information on the construction programme, HGVs and traffi c management, and noise. • Explain some of our early work on HGV movements and some early ideas on how we manage them

HS2 • Talk about how we tunnel and give indications of when our tunnel Route boring machine will reach Chalfont St Peter

Chesham Great Missenden The information we are sharing today is in the early stages of design.

Chilterns Little Missenden We have a team of experts here today so please feel free to ask any AONB Amersham questions you may have.

Section C1

Who are ALIGN?

Chalfont We are a joint venture of three international and privately owned High Wycombe St Giles Maple Cross infrastructure companies - Bouygues Travaux Publics, a subsidiary of

Beaconsfield Chalfont Bouygues Construction, Sir Robert McAlpine, and VolkerFitzpatrick. St Peter We have experience both in the UK and worldwide in delivering high- profi le infrastructure projects, safely, on time, and on budget. Gerrards Cross

Colne Valley Ruislip Regional Park In July 2017, we were awarded the Stage 1 contract to design the HS2 Route C1 section of the HS2 route. The C1 route includes the Colne Valley

Service Layer Credits: Contains OS data © Crown Viaduct and the Chiltern Tunnel. Copyright and database right 2018 Chalfont St Peter Vent Shaft

What is a vent shaft? Vent shafts are vertical openings connecting underground tunnels to the surface and open air. The purpose of a vent shaft is to: • Enable the smoke produced in the event of a fi re to be extracted in a controlled way, and provide fresh air to create smoke-free evacuation routes to the other tunnel through cross passages • Provide access for emergency services • Maintain air quality within the tunnel

What is a headhouse?

Chesham Lane The vent shaft has buildings on the surface and these are called headhouses. The headhouse is the only visible part of the structure once it is complete. The buildings house Location of Vent Shaft equipment including fi re control systems and ventilation systems for the railway tunnels.

Where is the Chalfont St Peter Headhouse located? The Chalfont St Peter Vent Shaft will be located approximately 50 metres from Chesham Lane to the south of Ashwell’s Farm. How to construct a vent shaft

Constructing a vent shaft includes a number of detailed activities. Each activity has varied lorry movements, working hours (including outside of core working hours) and noise levels.

Indica ve construc on mescales for Chalfont St Peter Vent Sha Noise Each construction activity has the potential Site setup 4 Months to have noise impacts. We will be taking Ground Treatment measures to minimise noise such as those (Dissolution feature) 2 Months listed below. Shaft wall construction (D walls) (based on extended hours) 4 Months Tackle noise at sources, for example, by Grouting 1.5 Months using quiet and low vibration equipment, reviewing the construction Main earthworks excavation 4 Months programme and the location of equipment on site. Access construction, shaft base slab and tunnelling machine 2.5 Months reception works (collar)

Arrival of TBMs through shaft 3 Months Screening, for example, by perimeter hoarding or temporary stockpiles Ventilation Adit construction 8 Months

Basement levels, shaft lining, internal structures (lifts, stairs etc), 14 Months basement levels

Construction of Headhouse and (Potential to overlap with work in row above) installation of equipment 17 Months At receptor by providing noise insulation

Estimated Total Time (not including overlapping activities) 57 Months

*BOLD items indicate activities generating the highest relative lorry numbers Noise mitigation hierarchy Construction Traffi c Primary lorry route for Chalfont St Peter Types of vehicles Vent Sha There will be several diff erent types of vehicles required to construct the vent shaft. The most common vehicles will include cement trucks and dumper trucks. Vent Shaft

Epilepsy Society/ Safety features Care Home The safety of all road users is of the utmost importance. • Logistic route safety improvements • Rural and urban Main where required driver training Compound • Road and junction assessment and • Committed to: improvement Montessori Robertswood • Enhanced safety equipment (3600 Nursery School cameras, side underun guards etc.) Keeping track of vehicles In order to keep track of our vehicles and manage them, we intend to use: • Manage/release holding areas • Real-time electronic vehicle logging • Clearly signed routes • Real-time adaption of construction traffi c to reduce impact on local roads Checks and balance More than 24 one way trips (12 HGVs) per day requires approval from qualifying planning authority.

Routes identifi ed Existing road Ongoing engagement Draft local traffi c Route improvement Schedule 17 application in the Environmental condition and with County Council & management plans and maintenance plans and approval Statement capacity assessments key stakeholders Early design work

The Chalfont St Peter Vent Shaft and headhouse (the building on top of the vent shaft) is still in early design. This section gives an overview of our work to date. In early 2019, we will hold a round of local public engagement to seek your views and ideas on our design.

Challenging the HS2 specifi cation Agricultural in size and appearance, rather than industrial. In agreement with HS2, we have:

• Reduced the height of the headhouse by approximately two metres by locating equipment into a basement

• Reduced the operational size of the compound

• Reduced the diameter of the vent shaft from circa 30 metres to 14.2 metres, reducing the number of lorries required for earthworks signifi cantly Looking through the vegetation - proposed • Moved the shaft further away from Chesham Lane to maximise opportunity for screening

Reducing the operational size of the compound

Year one - proposed

Hybrid Bill Our proposal Year 15 - proposed Early design work

We have been working closely with the Chilterns AONB panel to develop our early designs to ensure that the design approach integrates into the Chilterns sympathetically. We will be seeking your views and ideas early next year. In particular, we will be asking for views and ideas on the façade of the headhouse and landscaping. Early concept design and material precedents Landscape Concept

The landscape concepts look to integrate the buildings and compound within their rural setting, using the character of existing tree belts and gently undulating pasture, to help inform the design approach. Proposals include retaining mature trees and hedgerows around the site boundary and reinstating grassland to provide important wildlife habitats. A very subtle shaping of the ground to create shallow drainage ponds, and to provide some elevation to new tree planting to help screen the buildings, is also being considered. Tunnelling

180

Our tunnel boring machine This pressure balance provides additional 170

160 Following an in-depth review of the control to prevent any groundwater from 150 140 information provided by the Ground entering the tunnel during construction and 130 120 VENT SHAFT N53

CHALFONT ST PETER N153 protects against any movement of the slurry N52 110 Investigation, we are proposing to use two N160 N5 100 N4

into loose or fragmented geological strata. 90 N44 Variable Density Tunnel Boring Machines Elevation (m) 80 (TBM) for the 15.6km tunnels through the 70 Pre-cast concrete tunnel segments are 60 Chilterns. This type of TBM is able to cope 50 erected behind the cutting face of the TBM. 40 with changing ground conditions including 30 The tunnel segments are sealed with a double 20 soft chalks and fl ints. 10 CP12 CP11 CP10 CP9 CP8 CP7 CP6 CP5 CP4 CP3 PROJECT CHAINAGE 33+391 33+041 34+091 33+741 32+691 32+341 35+000 34+800 34+600 34+400 34+200 34+000 33+800 33+698 33+600 33+400 33+200 33+000 32+800 32+600 32+400 32+200 34+895 34+545 34+195 watertight gasket. 34+143 32+060 32+000 CHAINAGE

OPTIMIST FAULT

PESSIMIST

First Issue ------HS2 accepts no responsibility for any circumstances which arise from Legends/Notes: Zone Project/Contract P01.1 the reproduction of this document after alteration, amendment or abbreviation 28/03/18 or if it is issued in part or issued incompletely in any way. COLNE VALLEY VIADUCT & CHILTERN TUNNEL HS2- 1MC05 CONTRACT

Design Stage Discipline/Function ' Crown Copyright and database right 2017. All rights reserved. Registered in Ordnance Survey Licence number 100049190 Registration No. 06791686 SCHEME GEOTECHNICAL This special TBM was chosen to protect the Registered office: ' Crown Copyright material is reproduced with the permission of Land 2 Snow Hill, Drawing Title Drawn Checked Approved Registry under delegated authority from the Controller of HMSO. Queensway, Birmingham, B4 6GA G.JONES This material was last updated on 2017 and may not be copied, distributed, GEOLOGICAL LONGITUDINAL SECTION STA sold or published without the formal permission of Land Registry. Only an official copy of a title plan or register obtained from the Land Registry CHALFONT ST PETER SHAFT Date Scale Size may be used for legal or other official purposes. PAGE 1 OF 5 OFFICIAL 11/06/2018 1:4000 A1 Creator/Originator Code Suitability Drawing No. Rev. ALIGN JV S0 Initial Status or WIP 1MC05-ALJ-GT-DSK-C001-809526 P01.1 local groundwater and sensitive aquifers Rev Description Drawn Checked Con App HS2 App Scale with caution as distortion can occur. by maintaining a precise pressure balance Local geological conditions in front of the cutting face by creating a protective slurry made by mixing the local chalk with water. Inside a Tunnel Boring Machine (TBM)

SOUTH Chalfont Chalfont Little Chesham NORTH Amersham PORTAL St Peter St Giles Missenden Road PORTAL

2021 2022 2023 2024 Indicative programme for tunnelling