BTSYM June Lecture: Ground Movement Due to Circular Shaft Construction in London

On 6th June, BTSYM will be hosting Njemile Faustin and Professor Lord Robert Mair CBE FREng FRS FICE who will be presenting on the Ground Movements due to Circular Shaft Construction in London Clay.

Until now, there were few well-documented case studies of circular shafts, which made it difficult to estimate reliable ground movements during construction. Field observations of ground surface settlement were assembled during the construction of 27 circular shafts built for three major tunnelling projects in London: Crossrail, National Grid’s London Power Tunnels project and Transport for London’s Northern line extension. Two categories of shaft construction were identified: Support Before Excavation and Excavation Before Support. For the Support Before Excavation category, the shaft was first supported by pre-installed walls followed by excavation of the soil between the pre-installed walls. For the Excavation Before Support category, the ground was progressively excavated in sections followed by construction of the shaft lining. Careful interpretation of the field observations together with centrifuge model testing in the geotechnical centrifuge at Cambridge University provided new insight into the ground movements arising from circular shaft construction. Normalised charts were developed to estimate the settlement due to circular shaft construction in London Clay, with due consideration for different shaft geometries and construction methods.

The lecture will take place on 6^th June at ICE, starting at 18:00hrs with tea/coffee from 17:30 onwards. The poster can be found here. AECOM has kindly offered to buy the first round of drinks at the ICE bar afterwards. The lecture will also be streaming online, the link to which will be available on the day at : https://www.britishtunnelling.org.uk/?sitecontentid=5C0B03E1-56D8-4D8C-9E1C-151DA40DBB69

Date: 6th June, 06:00pm

Location: ICE, Telford Theatre