Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 243 Site investigation and information required on soil conditions 10 An introduction to pipe jacking and microtunnelling 3 SITE INVESTIGATION AND INFORMATION REQUIRED ON SOIL CONDITIONS SITE INVESTIGATION: GENERAL When designing and costing works to be carried out by pipe jacking, a thorough site investigation, both factual and interpretative, and report is required in order to determine the characteristics of the soils likely to be encountered, together with details of the water table in the vicinity. The site investigation should follow the guidance given in: • Eurocode 7: Geotechnical design - Part 1: General rules and Eurocode 7: Geotechnical design - Part 2: Ground investigation and testing • UK Specification for Ground Information (ICE Site Investigation Steering Group) • BTS Tunnel Lining Design Guide, Chapter 3, Geotechnical characterisation • All exploratory hole work, associated sampling, in situ testing and logging shall be carried out in accordance with techniques outlined in BS 5930:2015, BS EN ISO 14689-1:2003, BS EN ISO 14688-1:2002, BS1377:1990 and BS EN ISO 22476/3: 2005 as appropriate. • Closed-Face Tunnelling Machines and Ground Stability, produced by the British Tunnelling Society and the Institution of Civil Engineers (Thomas Telford Publishing), 2005 • Joint Code of Practice for Risk Management of Tunnel Works, prepared by the International Tunnelling Insurance Group, 2012 (supercedes BTS/API JCoP, 2003) DESK STUDY For all schemes a desk study should be carried out, assessing the available literature, maps, aerial photographs, utility plans and existing site investigations. The desk study is essential to help understand the broader geological and geotechnical issues, and should be used to determine the scope of any intrusive investigations. 3a) Typical ground information required for design and costing PROPOSED PIPE JACK Fill Fill Loose coarse sand and ballast Clay Sandstone Firm sand and gravel Clay Sandstone BOREHOLE BOREHOLE WATER WATER Rate of inflow slow Rate of inflow fast 1 3 2 2 3 1 4 0 5 6 7 8 9 10 11 12 13 Metres