Crossrail Geological Long Section: Post-Construction Update

Document type: Dataset
Author: John Davis EurGeol CGeol MSc DIC
Publication Date: 14/03/2017

  • Abstract

    The links provide access to two documents produced by GCG for Crossrail; a geological long section along the Crossrail alignment in London; and a report that provides detailed notes for the section along with some context for the production of the section.

    7A 025_2 Figure 1 post construction geological profile.jpg

    Prior to construction of Crossrail a large number of ground investigations were carried out for the project. The stratigraphic knowledge arising from this work was coupled with thirty party and historic borehole data to produce an initial long section along the Crossrail alignment to illustrate the likely geological conditions. This long section was updated towards the end of the main construction works with later Crossrail and 3rd party borehole data. This updated section is the subject of this report.

    The purpose of these sections was to provide an overview of the geological setting of the whole of Crossrail; they were not used directly in design or for construction.

    The locations of strata boundaries shown on the section are based on GCG’s interpretation of the available borehole logs. The scale of the section, the variable borehole density and the use of boreholes offset from the tunnel alignment all mean the strata boundary locations shown on the section are only indicative. In highly faulted zones individual faults are not shown. Faults are shown as planar and vertical, this is unlikely to be the case in practise.

    The Harwich Formation and Lambeth Group boundary has been re-interpreted and reclassified in some areas and this re-interpretation may differ from other earlier published works. These new findings are presented and discussed in detail in Appendix A and B of the report.

    The report also contains a series of explanatory notes for the long section. These are set out in Section 2.  Key findings from the revised Section are presented in Section 3.

  • Document Links

  • Authors

    Photo of John Davis

    John Davis EurGeol CGeol MSc DIC - Geotechnical Consulting Group

    John was seconded to the Chief Engineers Group within Crossrail from Geotechnical Consulting Group LLP from 2009 until July 2016.

    Within the Chief Engineers Group John was responsible for all Crossrail geotechnical matters east of Farringdon. Whilst at Crossrail John was also closely involved with the production of Geotechnical Baseline Reports for all the major Civils contracts. Prior to Crossrail John spent 20+ years as a geotechnical designer working on a diverse range of structures across the world, these included deep basements, embankments, tunnels, slopes and retaining walls. John was seconded to London Underground for a couple of years in the mid 90’s where he led a research programme on the impact of rising groundwater on the tube network.