DEEP ROTARY CORED BOREHOLES IN SOILS USING WIRELINE DRILLING

During early 1994 Soil Mechanics Limited carried out a site investigation for Nuclear Electric plc as part of the ongoing works for the proposed Sizewell C Power Station in Suffolk. The work included rotary cored boreholes put down to over 100m depth through shelly sands of the Crag deposits overlying clay and sand of the Lower London Tertiaries, and penetrating the underlying chalk bedrock. The purpose of the cored boreholes was to obtain a complete stratigraphic profile and obtain high quality core samples, suitable for subsequent small strain triaxial and dynamic laboratory testing. Some boreholes were logged by wireline geophysical methods and permanent plastic liners were also installed for cross hole seismic logging. The borehole construction techniques are discussed in detail, with particular reference to the drilling muds used to aid core recovery in the weak formations and provide interim stability of boreholes left uncased during geologging and installation of permanent grouted liners. The use of a semi-rigid plastic liner in the inner core barrel to assist in core handling is described, together with core sample selection, preservation and storage for subsequent transport and testing off site. (A) For the covering abstract see IRRD 883023.

Language

  • English

Media Info

  • Pagination: p. 269-80

Subject/Index Terms

Filing Info

  • Accession Number: 00729272
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 0-7277-2513-0
  • Files: ITRD
  • Created Date: Dec 12 1996 12:00AM