01. – The importance of site investigation Page 2 – 4
1.02 – Trial PitsPage 4
1.03 – Auger holesPage 4 – 5
1.04 – BoreholesPage 5 – 7
1.05 – Soil samplingPage 7
1.06 – In-situ testingPage 8
1.07 – Quasi-static cone penetration testingPage 8 – 9
1.08 – Dynamic probingPage 10
1.09 – The Standard Penetration TestPage 11
1.10 – Field vane testPage 12
1.11 – Classifications of SoilsPage 13
1.12 – Size range of grainsPage 13 – 14
2.00 – Walk over survey Report Page 15 – 19
2.01 – SummaryPage 19 – 20
Appendix ‘A‘ Walk over site drawingPage 21
Appendix ‘B’ Site photos and Site PositionPage 22
1.01 -The importance of site investigations
Any site investigations should be carried out following code of practice for site investigation ‘BS 5930’ according to the British Standards. The building standards provide us with the best practice and provide a good guide on how to proceed and complete a building project.
Site investigation is the gathering of all the information on ground conditions which might be relevant to design and construction on a particular site. A desk study is the first stage of investigation. This involves checking existing records, such as geological maps of the site. The desk study, and a walk over survey, will indicate the probable ground and groundwater conditions and the problems they might pose.
A desk top survey can be done at the office with little expense, you an find the information from the following places:
Local council – will provide information on any development restrictions close or near to the site.
Utility companies / water board - will provide information on existing water sources, provisions, existing sewers and their location. Previous structures made up ground, quarries and ground mines.
Land registry – will provide information on boundaries / ownership / responsibility and maintenance.
National Geological society of Great Britain – from this you will be able to establish the land of the proposed site.
Local library – will be able to provide books containing maps and detailed history of the land usage.
All the above are very essential to be able to obtain information that will cost very little and take up little time. From this you will then do a walk-over survey.
The walk-over survey is an important part of the site investigation process which should always be carried out. Used in conjunction with a good desk study, it provides valuable information which cannot be obtained in any other way.
The object of the survey is to check and make additions to the information already collected during the desk study.
At an early stage, a thorough visual examination should be made of the site. The extent to which ground adjacent to the site should also be examined is, in general, a matter of judgementThe site and its surrounding area should be visited and covered carefully on foot. This stated in BS 5930 page 4, paragraph 6.3 Site reconnaissance.
Local authorities, local inhabitants and people working in the area, such as builders, electricity and gas workers, should be questioned to obtain the benefit of their local knowledge. A structured report is then produced from the information gathered at the site and from local enquiries. The site inspection involves walking across the whole site, making full use of the information obtained during the desk study. It is useful to have available maps and photographs that have been obtained and it is necessary to prepare a special site map, at a suitably large scale. On this should be marked by hand the geology and other features of special interest that have been noticed during the desk study. During the site inspection the position of any further features (e.g. trees, hedges, pits, exploratory holes) can be marked on the map, and the existence of previously identified features can...