Chalfont St Peter vent shaft

There are four ventilation shafts and one intervention shaft in the tunnel across the Chilterns. These would also be used for emergency access during operation. The first of these is in Chesham Lane, Chalfont St Peter.

All the ventilation shafts used the same diaphragm wall construction method. Ventilation fans will be housed in a basement below a single storey headhouse. The construction compound will be in place for seven years. The shaft is 66 metres deep and is the deepest of the shafts. The tunnels are 47 metres below ground and the tunnel boring machines reached here in March 2022. The site will also house an autotransformer station.
The shaft is due to be completed early in 2025.

The access route to the compound is via a newly constructed temporary haul road directly to the A413 then to the A40 and the M40. All HGVs will turn left when leaving the haul road. The junction is controlled by temporary traffic lights.

PRoW (Public Right of Way) CSP 10 is diverted east around the construction compound before joining the existing footpath CSP 9 south of The Brow for the duration of construction and then reinstated along its original alignment.

Beyond the shaft the route continues towards Chalfont St Giles tunnelling under the River Misbourne for the first time. It passes under the Co-op store in the middle of the village and then on towards the Chalfont St Giles vent shaft.

Chalfont St Peter vent shaft looking east – Apr. 2016 (03_131)
Chalfont St Peter vent shaft looking east – Oct. 2020 (03_129)
Chalfont St Peter vent shaft headhouse – May 2024 (03_152)
Construction of vent shaft plenum (vent outlet) – May 2024 (03_151)
Headhouse under construction – Feb. 2024 (03_150)
Chalfont St Peter vent shaft looking east – Nov. 2023 (03_149)
Chalfont St Peter vent shaft headhouse – Jan. 2024 (03_148)
Vent shaft and headhouse basement – Oct. 2022 (03_136)
Chalfont St Peter vent shaft haul road as it crosses PRoW CSP 10 – Apr. 2023 (03_147)
Looking south across the Chalfont St Peter vent shaft – Apr. 2023 (03_146)
Chalfont St Peter vent shaft basement looking west – Apr. 2023 (03_145)
Vent shaft basement looking east – Apr. 2023 (03_144)
Chalfont St Peter vent shaft basement constructed using secant piling – Apr. 2023 (03_143)
Removing the top of the diaphragm wall using hydro demolition – Apr. 2023 (03_142)
Looking across the shaft to the basement that will house the fans – Apr. 2023 (03_141)
Chalfont St Peter vent shaft from top to bottom over fifty metres down – Apr. 2023 (03_140)
Chalfont St Peter vent shaft lift descends twelve levels – (Apr. 2023 (03_139)
Cutting through from the vent shaft into the up line tunnel – Apr. 2023 (03_138)
Chalfont St Peter vent shaft looking east – Oct. 2022 (03_137)
Looking east along Chesham Lane – Jun. 2022 (03_135)
Chalfont St Peter vent shaft looking west – Jun. 2022 (03_134)
Chalfont St Peter vent shaft looking east – Apr. 2022 (03_133)
Chalfont St Peter vent shaft soon after the TBMs have passed below – Apr. 2022 (03_132)
Chalfont St Peter vent shaft looking west- Jun. 2020 Roger Allen (03_118)
Chesham Lane looking west – Mar. 2021 (03_117)
Chalfont St Peter vent shaft looking west – Mar. 2021 (03_116)
A413 junction with haul road looking north – Dec. 2020 (03_112)
Vent shaft diaphragm wall cutter – Oct. 2020 (03_109)
Chalfont St Peter vent shaft looking east – Oct. 2020 (03_105)
Chesham Lane looking east – Sep. 2020 (03_ 102)
Chesham Lane looking east – Sep. 2020 (03_101)
Chesham Lane west – Sep. 2020 (03_100)
PRoW CSP 10/1 looking east – Sep. 2020 (03_99)
PRoW CSP 10/1 looking north – Sep. 2020 (03_98)
PRoW CSP 10/1 looking west – Sep. 2020 (03_97)
PRoW CSP 10/1 – Aug. 2020 (03_94)
Chesham Lane looking west – Aug. 2020 (03_93)
Chalfont St Peter vent shaft – Aug. 2020 (03_92)
Chalfont St Peter vent shaft – Aug. 2020 (03_90)
PRoW CSP10 diversion looking east – Aug. 2020 (03_69)
Chalfont St Peter vent shaft – Aug. 2020 (03_68)
Chalfont St Peter vent shaft – Aug. 2020 (03_67)
Chalfont St Peter vent shaft – Aug. 2020 (03_66)
Chalfont St Peter vent shaft – Aug. 2020 (03_65)
Chalfont St Peter vent shaft – Jun. 2020 (03_45)
Haul road west from PRoW CSP 10/1 – May 2020 (03_35)
Haul road crossing PRoW CSP 10/1 looking west – May 2020 (03_34)
Haul road looking east from PRoW CSP 10/1 – May 2020 (03_33)
Haul road entering the vent shaft compound looking east – May 2020 (03_32)
Haul road entering the vent shaft compound looking west – May 2020 (03_31)
Chalfont St Peter vent shaft – May 2020 (03_30)
PRoW CSP 10/1 – May 2020 (03_29)
PRoW CSP 10/1 – May 2020 (03_28)
PRoW CSP 10/1 diversion looking east – May 2020 (03_27)
Chalfont St Peter vent shaft – May 2020 (03_26)
PRoW CSP 10/1 diversion looking east – May 2020 (03_25)
PRoW CSP 10/1 diversion looking east – May 2020 (03_24)
(40) PRoW CSP 10/1 diversion looking north – May 2020 (03_23)
(41) PRoW CSP 10/1 diversion looking north – May 2020 (03_22)
(42) PRoW CSP 10/1 diversion looking east – May 2020 (03_21)
PRoW CSP 10/1 diversion looking north – May 2020 (03_20)
PRoW CSP 10/1 diversion looking north – May 2020 (03_19)
PRoW CSP 10/1 diversion looking north – May 2020 (03_18)
PRoW CSP 9/3 looking north towards The Brow – May 2020 (03_17)
PRoW CSP 10/1 looking south – Mar. 2020 (03_16)
PRoW CSP10 looking north – Mar. 2020 (03_15)
PRoW CSP10 looking east – Mar. 2020 (03_14)
PRoW CSP10 looking west – Mar. 2020 (03_13)
Chesham Lane looking east – May 2019 (03_142)
Chesham Lane looking north – May 2019 (03_141)
Chesham Lane looking west – May 2019 (03_140)
Chesham Lane looking east – Mar. 2019 (03_139)
Chesham Lane looking east – Mar. 2019 (03_138)
Chesham Lane looking west – Apr. 2019 (03_137)
Ground investigations – Aug. 2012 (03_136)
Chesham Lane looking east – Apr. 2016 (03_135)
Chesham Lane looking west – Apr. 2016 (03_134)
Looking east across the vent shaft site – Apr. 2016 (03_133)
Looking east across the vent shaft site towards Chesham Lane – Apr. 2016 (03_132a)
Chalfont St Peter vent shaft looking east – Mar. 2019 (03_132)