Chesham Road Vent Shaft

(Provisional schedule, Nov 2018
Reconstructed from Phone image)

Chesham Road Vent Shaft schedule
Main Activities Indicative Timescales Current Dates
Site Setup 4 months July 2021
Ground Treatment (Dissolution Feature) 1 month November 2021
Shaft (D-wall) construction 4.5months - extended hrs December 2021
Main Earthworks Excavation 1.5 months April 2022
Access construction, shaft base slab and tunnell boring machine reception 4.5 months June 2022
Construction of pressure relief adit 10 months October 2022
Arrival of TBMs through shaft 3 months August 2023
Shaft lining, internal structures 13 months November 2023
Construction of Headhouse 12 months October 2024
Estimated total time 52 months  


Entries shown in bold will generate the most lorry movements. The shaft construction timescale assumes concrete pouring continuously for 12 hr shifts. This requires an exemption from standard working hours.