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X-WR-CALNAME:Hertfordshire Geological Society
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X-WR-CALDESC:Events for Hertfordshire Geological Society
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TZOFFSETFROM:+0000
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DTSTART:20210101T000000
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DTSTART;TZID=UTC:20220414T193000
DTEND;TZID=UTC:20220414T210000
DTSTAMP:20260423T171219
CREATED:20211202T164129Z
LAST-MODIFIED:20220417T070212Z
UID:6611-1649964600-1649970000@www.hertsgeolsoc.org.uk
SUMMARY:Percy Evans Lecture on Tunnelling the Chilterns:
DESCRIPTION:Progress so far; understanding the risks; and how technology\, planning and logistics help address the challenges of tunnelling through a highly fractured chalk aquifer. \ngiven by David Eve (ALIGN\, Head of Engagement & Compliance for HS2) \nAbstract: \nWho are Align and how does the company fit within the HS2 structure? This leads on to an overview of HS2. The HS2 route is split into various sectors\, so I need to give an overview of Sector C1. What progress have we made to date and what were the results of the Ground Investigation? \nWhat are the risks? \n\nVolume loss; frac in and out;\nLoss of slurry to surface;\nLoss of ground stability within excavation chamber;\nLoss of air to surface (if intervention conducted under hyperbaric conditions);\nLoss of grout to surface; and over-excavation within excavation chamber.\nLeading to: Ground deformation; and excessive movement of structures.\n\nHow do we mitigate for these risks? \n\nOverview of the ‘system’ – TBM to Slurry Treatment Plant;\nPre-treatment where required (shafts);\nTechnology of the TBM (selection) – speed\, variable slurry density control\, anulus Grouting to maintain <1% volume loss\, continuous monitoring (MobyDic\, borehole data\, ground instrumentation) and adaption;\nLogistics and processing of slurry;\nExclusion zones and planning of appropriate maintenance stops;\nSecuring of land in higher risk areas.\n\nView this talk in the Members’ Section.
URL:https://www.hertsgeolsoc.org.uk/event/percy-evans-lecture-on-tunnelling-the-chilterns/
LOCATION:over Zoom
CATEGORIES:Talks
ATTACH;FMTTYPE=image/jpeg:https://www.hertsgeolsoc.org.uk/wp-content/uploads/2022/03/HS2-High-Speed-Rail.jpg
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