Amersham 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 third of these is in Whielden Lane, Amersham. 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 site will also house an autotransformer station.

The vent shaft depth is 40 metres and the tunnels are 30 metres below ground. The tunnel boring machines reached here in Feb. 2023. The vent shaft is due to be completed by May 2025.

The approved access route for HGVs is via the A404, A413, A355 to Beaconsfield then the A40 and the M40. A footpath and cycleway was diverted for a year and then reinstated alongside Whielden Lane. There have been alterations to the junction of Whielden Lane and the A404 and temporary traffic lights installed to control the junction. There have also been slight alterations to the junctions of the A404 with the A413 and the A413 with the A355 Gore Hill.

North of the vent shaft the route continues under the A404 and then passes between Shardeloes and Shardeloes Lake before tunnelling under the River Misbourne for the second time and then crosses under the A413 shortly before reaching the Little Missenden vent shaft.

* On May 13th 2023 a sinkhole opened up in Shardeloes field about a hundred metres to the south of Shardeloes lake. The hole was approximately six metres in diameter and five metres deep. During the night, the ground had given way and the sinkhole had been created, thirty-two metres above the recently excavated westerly bore of the Chiltern tunnel.
Following ground investigations the cavity was backfilled using chalk brought in from the Little Missenden vent shaft. Landscape remediation will follow a period of ground stabilisation.

Amersham vent shaft looking west – Oct. 2019 (05_286)
Amersham vent shaft headhouse construction from Whielden Lane – Apr. 2024 (05_335)
Looking south towards construction of the auto transformer station and headhouse – Apr. 2024 (05_334)
Looking south towards construction of the headhouse – Apr. 2024 (05_333)
Autotransformer station under construction – Feb. 2024 (05_332)
Vent outlet under construction – Feb. 2024 (05_331)
Construction of the circular headhouse – Feb. 2024 (05_330)
Amersham vent shaft looking west – Jan. 2024 (05_329)
Amersham vent shaft looking south east – Nov. 2023 (05_328)
Amersham vent shaft looking south – Nov. 2023 (05_327)
Looking south towards the top of the Amersham vent shaft – Nov. 2023 (05_326)
Amersham vent shaft looking south – Aug. 2023 (05_325)
The sink hole that appeared between Shardeloes and Shardeloes Lake – Jun. 2023 (05_323)
Looking north from PRoW AMS 26/3 towards the sink hole – May 2023 (05_322)
Sink hole looking towards Shardeloes Lake (Haydon Bailey)- May 2023 (05_321)
Looking north along PRoW AMS 26/3 – Sep. 2023 (05_320)
Looking across the temporary access track towards Little Missenden vent shaft – Sep. 2023 (05_319)
Dump truck approaching PRoW AMS 26/3 marshalled crossing – Sep. 2023 (05_318)
Dump truck passing below Shardeloes – Sep. 2023 (05_317)
Material excavated from the sink hole – Sep. 2023 (05_316)
Chalk offloaded directly in to the cavity – Sep. 2023 (05_315)
Sink hole looking east towards Shardeloes Lake – Sep. 2023 (05_314)
Looking north along the tunnel route towards Little Missenden vent shaft – Sep. 2023 (05_313)
Looking north towards the River Misbourne and the Little Missenden vent shaft – Sep. 2023 (05_312)
Amersham vent shaft looking east – Jul. 2023 (05_311)
Amersham vent shaft looking south towards the top of the shaft – Jul. 2023 (05_310)
Amersham vent shaft looking east – Jun. 2023 (05_309)
Top of the Amersham vent shaft – May 2023 (05_306)
TBM Cecilia is receiving maintenance 30 metres below the basement – Feb. 2023 (05_300)
TBM Florence has passed 30 metres under eastern side of the shaft – Feb. 2023 (05_299)
Tie beams across the vent shaft basement – Jan. 2023 (05_298)
Vent shaft and headhouse basement – Oct. 2022 (05_296)
Construction of shaft basement levels – Aug. 2022 (05_295)
Amersham vent shaft looking east – Aug. 2022 (05_294)
Amersham vent shaft looking west – Aug. 2022 (05_293)
Amersham vent shaft looking east – Jun. 2022 (05_291)
Construction of internal vent shaft structures – Jun. 2022 (05_290)
Amersham vent shaft looking north – Apr. 2022 (05_288)
Amersham vent shaft – Apr. 2022 (05_287)
Amersham vent shaft looking north – Jul. 2021 (05_285)
Shaft excavation and secant piling – Feb. 2022 (05_284)
Spoil being removed to the south tunnel portal for use in landscaping – Feb. 2022 (05_282)
Amersham vent shaft – Jan. 2022 (05_278)
Amersham vent shaft looking west – Jan. 2022 (05_277)
Amersham vent shaft excavation – Jan. 2022 (05_276)
Amersham vent shaft excavation – Jan. 2022 (05_274)
Numbered diaphragm wall panels – Jan. 2022 (05_272)
Amersham vent shaft excavation – Jan.2022 (05_271)
Approx. five grabs fill a truck – Jan. 2022 (05_270)
Amersham vent shaft excavation – Jan. 2022 (05_269)
Spoil being removed to the south tunnel portal site – Jan. 2022 (05_268)
Secant piling to create basement below the headhouse – Jan. 2022 (05_266)
Steel reinforcing cages for alternate piles – Jan. 2022 (05_265)
Whielden Lane looking west – Nov. 2021 (05_261)
Secant pile drilling rig – Nov. 2021 (05_260)
Whielden Lane looking east – Nov. 2021 (05_259)
Preparing secant pile drilling rig – Nov. 2021 (05_258)
A404 looking south – Nov. 2021 (05_256)
Preparing for shaft excavation – Nov. 2021 (05_255)
Air quality & noise monitoring – Nov. 2021 (05_254)
Amersham vent shaft – Nov. 2021 (05_251)
Amersham vent shaft looking south – Nov. 2021 (05_248)
Amersham vent shaft from Whielden Lane – Oct. 2021 (245)
Overnight working on excavating the vent shaft – Oct. 2021 (05_243)
Whielden Lane looking west – Sep. 2021 (05_240)
Diaphragm walling completed – Sep. 2021 (05_239)
Looking west from PRoW AMS 21/3 – Sep. 2021 (05_238)
Contractors office accommodation – Jul. 2021 (05_233)
Diaphragm wall cutting rig – Jul. 2021 (05_230)
Diaphragm wall cutting rig – Jul. 2021 (05_228)
Bentonite filling diaphragm wall void- Jul. 2021 (05_227)
Top of diaphragm wall – Jul, 2010 (05_226)
Bentonite de-watering plant – Jul. 2021 (05_225)
Shaft rim cutter – Jul 2021 (05_223)
Cutter head – Jul. 2021 (05_222)
Wheel washing of vehicle leaving compound – Jul. 2021 (05_221)
Dust suppressing – Jul. 2021 (05_220)
Amersham vent shaft looking east – Jul. 2021 (05_218)
Looking east from Whielden Lane – Jul. 2021 (05_216)
Amersham vent shaft looking west – Jul. 2021 (05_212)
Amersham vent shaft looking west – Jul. 2021 (05_211)
Amersham vent shaft looking east – Jul. 2021 (05_208)
Amersham vent shaft murals – Jul. 2021 (05_207)
Amersham vent shaft murals – Jul. 2021 (05_206)
Amersham vent shaft murals – Jul. 2021 (05_204)
Amersham vent shaft murals showing proposed head house design – Jul. 2021 (05_203)
Whielden Lane looking west – Jun. 2021 (05_200)
Amersham vent shaft looking north – Jun. 2021 (05_199)
Amersham vent shaft looking north – Jun. 2021 (05_198)
Wheel washing on exiting compound – Jun. 2021 (05_197)
Amersham vent shaft looking east from A404 – Jun. 2021 (05_196)
Diaphragm wall cutter – Jun. 2021 (05_195)
Whielden Street looking west – May 2021 (05_191)
Amersham vent shaft looking west – May 2021 (05_190)
Amersham vent shaft looking east – May 2021 (05_188)
Amersham vent shaft looking east from the A404 – May 2021 (05_187)
Whielden Lane looking east – Apr. 2021 (05_181)
Amersham vent shaft looking east – Apr. 2021 (05_178)
Amersham vent shaft looking north – Apr. 2021 (05_175)
Whielden Lane looking north – Apr. 2021 (05_174)
Amersham vent shaft looking east – Apr. 2021 (05_172)
Whielden Lane re-opens after nine month closure – Apr. 2021 (05_170)
Whielden Lane looking east- Apr. 2021 (05_165)
Amersham vent shaft looking north – Apr. 2021 (05_164)
Amersham vent shaft looking north – Apr. 2021 (05_163)
Amersham vent shaft looking north – Apr. 2021 (05_161)
Whielden Lane looking east – Apr. 2021 (05_160)
Amersham vent shaft looking east – Apr. 2021 (05_158)
A404 junction with Whielden Lane looking east – Apr. 2021 (05_157)
Whielden Street looking east – Mar. 2021 (05_154)
Amersham vent shaft looking north – Mar. 2021 (05_153)
Whielden Street footpath looking west – Mar. 2021 (05_152)
Amersham vent shaft looking east (05_150)
Whielden Lane footpath looking west – Feb. 2021 (05_148)
Whielden Lane footpath looking east – Feb. 2021 (05_147)
Amersham vent shaft looking west – Feb. 2021 (05_145)
Amersham vent shaft looking west – Feb. 2021 (05_144)
Amersham vent shaft looking east – Feb. 2021 (05_143)
Whielden Lane looking east – Feb. 2021 (05_140)
Whielden Lane footpath looking west – Dec. 2020 (05_130)
Amersham vent shaft looking south – Dec.2020 (05_129)
Whielden Lane footpath looking east – Dec. 2020 (05_127)
Amersham vent shaft looking east – Dec. 2020 (05_126)
Whielden Street looking west – Nov. 2020 (05_122)
Whielden Street looking west – Nov. 2020 (05_121)
Whielden Street looking east – Nov. 2020 (05_120)
Amersham vent shaft looking south – Nov. 2020 (05_119)
Amersham Vent Shaft looking west – Oct. 2020 (05_114)
Amersham Vent Shaft looking east – Oct. 2020 (05_113)
Amersham Vent Shaft looking east – Oct. 2020 (05_111)
Amersham vent shaft looking west – Oct. 2020 (05_108)
Amersham vent shaft looking north – Oct. 2020 (05_107)
Whielden Lane looking west – Sep. 2020 (05_104)
Amersham vent shaft looking west – Sep. 2020 (05_102)
Amersham vent shaft looking east – Sep. 2020 (05_98)
Whielden Lane looking west – Sep. 2020 (05_94)
Whielden Lane looking east – Sep. 2020 (05_93)
Looking east across the Amersham vent shaft – Sep 2020 (05_92)
Looking north west across Amersham vent shaft – Sep. 2020 (05_88)
Whielden Lane looking east – Aug. 2020 (05_85)
Amersham vent shaft looking east – Aug. 2020 (05_84)
Whielden Lane looking east – Aug. 2020 (05_83)
Whielden Lane looking west – Aug. 2020 (05_80)
Amersham vent shaft looking west – Aug. 2020 (05_78)
Amersham vent shaft looking north – Aug. 2020 (05_77)
Amersham vent shaft looking east – Aug. 2020 (05_75)
Whielden Lane looking east – Aug. 2020 (05_73)
Whielden Lane looking west – Jul. 2020 (05_72)
Whielden Lane looking west – Jul. 2020 (05_70)
Amersham vent shaft looking north – Jul. 2020 (05_69)
Whielden Lane looking east – Jul. 2020 (05_67)
Whielden Lane looking east – Jul. 2020 (05_66)
Whielden Lane looking east – Jul. 2020 (05_65)
Amersham vent shaft looking east – Jul. 2020 (05_64)
Whielden Lane looking west – Jul. 2020 (05_61)
Amersham vent shaft looking west – Jul. 2020 (05_60)
Whielden Lane looking east – Jul. 2020 (05_58)
Whielden Lane looking east – Jul. 2020 (05_57)
A404 looking west – Jul. 2020 (05_53)
Whielden Lane looking south – Jul. 2020 (05_51)
Amersham Hospital shuttle bus to Gore Hill running during road closure – Jul. 2020 (05_50)
Whielden Lane closure looking west – Jul. 2020 (05_47)
Whielden Lane footpath looking west – Jul. 2020 (05_46)
Across the vent shaft looking east – Jul. 2020 (05_45)
Whielden Lane footpath looking west – Jul. 2020 (05_44)
Across the vent shaft looking east – Jul. 2020 (05_42)
A404 looking east – Jul. 2020 (05_39)
A404 looking east Jul. 2020 (05_38)
Across the vent shaft looking west – Jul. 2020 (05_36)
Whielden Lane looking east – May 2020 (05_32)
Whielden Lane footpath and cycleway looking west – May 2020 (05_31)
Whielden Lane footpath and cycleway looking west – May 2020 (05_30)
Whielden Lane footpath and cycleway looking west – May 2020 (05_29)
Junction of Whielden Lane and the A404 – May 2020 (05_27)
A404 looking west – May 2020 (05_25)
A404 looking west – May 2020 (05_24)
A404 looking east – May 2020 (05_23)
Junction of A404 and Whielden Lane looking east – May 2020 (05_22)
Whielden Lane looking east – Jan. 2020 (05_21)
Whielden Lane footpath looking east – Jan. 2020 (05_20)
Whielden Lane looking west – Mar. 2020 (05_19)
Whielden Lane looking west – Feb. 2020 (05_18)
Whielden Lane footpath looking west – Feb. 2020 (05_17)
Whielden Lane footpath looking east – Feb. 2020 (05_16)
Whielden Lane footpath looking east – Mar. 2020 (05_15)
Amersham Vent Shaft looking south – Mar. 2020 (05_13)
Amersham Vent Shaft – Apr. 2016 (05_12)
Whielden Street looking west – Apr. 2013 (05_10)
Whielden Lane looking west – May 2019 (05_09)
Whielden Lane looking west – Mar. 2019 (05_08)
Whielden Lane looking north – Mar. 2019 (05_07)
Whielden Lane looking east – May 2019 (05_06)
Whielden Lane footpath looking west – Mar. 2019 (05_05)
Whielden Lane footpath looking east – May 2019 (05_04)
Whielden Lane footpath looking east – Apr. 2013 (05_03)
A404 looking east – Aug. 2016 (05_02)
A404 looking west – Aug. 2019 (05_01)