Introduction to Ground Modelling
The purpose of a site investigation is to identify the ground conditions which may affect a particular development and to arrive at an understanding of the site and immediate surroundings which will allow safe and economic development. (AGS Guidelines for Good Practice in Site Investigation (Issue 2) Published by the Association of Geotechnical and Geoenvironmental Specialists)
GroundModels provides a unique interactive learning system designed to raise the competence of those in Ground Engineering who have to arrive at an understanding of the site and immediate surroundings.
Learning of this kind was initiated by Dr Herbert Lapworth in his original course of Geology for Engineers for the Institution of Civil Engineers in London in 1907; Dr Lapworth was awarded the Institution’s Gold Medal for this work. His course was then transferred to what is now Imperial College London where it formed the roots for Engineering Geology.
Making such exercises inter-active was later developed at Delft University by Prof. David Price who incorporated the means of “purchasing” ground investigation data. The exercises were tested, used and developed at Imperial and proved to be immensely powerful instruments for teaching.
- The answers to the questions require the maps of the sites to be printed and the graphical solutions required to be superimposed either directly onto the maps or onto tracing paper overlays; these then provide the paper basis for a hard-copy file of work demonstrating the competences of the user.
- The hard-copy file of work can usefully be augmented by print-outs of the Resources provided including the Questions and the Answers, as the latter demonstrate the correctness of the user’s constructions and calculations based on them.
- Use of the Geo-browser (the inter-active part of the exercises) can also be tabulated by downloading the vertical profiles obtained by using it and the notional cost of that data; a correct answer at low cost will reflect either a good understanding of both the problem and its means of solution, or luck. It is very unlikely that luck will play a significant part of the 4 problems in each of the three Modules.
- Answers to the Self Assessment Questions should also be printed together with the evidence used to answer the question.
- Each Module will probably take 8 hours of effort; the three Modules taken together will probably require 24hours work for most users. The learning curve is steep but the problems increase in severity both within a Module and between one Module and the next.
Member of revision committees and working parties for NERC, BSI, CIRIA , IAEG and Geological Society.
Andrew W Thompson
A geographer and cartographer since 1980, Andrew Thompson has managed geographic and mapping projects for central government departments, urban redevelopment corporations, and numerous geographic information publishers.
In his work for Groundwork Maps he specialises in project planning, geospatial analysis and geovisualisation. Recent work includes street networks, analysis for infrastructure planning, cartography (his maps have won a British Cartographic Society's Design Award medal) and the production of atlases, and ground modelling training courses.
He is a long-time Fellow of The Royal Geographic Society, and The British Cartographic Society.
- Read, understand and interpret geological maps and stratigraphical successions.
- Integrate topographic and land use information of different ages with the geology.
- Incorporate data on rivers and springs into the geology.
- Relate borehole data and vertical profiles to the local geology.
- Interpret vertical profiles from borehole records.
- Form an informed view of water tables on site.
- Construct vertical cross sections in different directions so as to define basic site geology in 3D.
- Develop a working knowledge of the concepts of dip and strike.
- Construct 3-point solutions for defining and predicting geological and hydrogeological surfaces across a site in 3D space.
- Use 3-point solutions for predicting sub-outcrop maps for the geology on site including those of mined coal
- Detect the likely presence and location of faults and assessment of their likely displacement.
In order to do well it is advised that you check your ability with the following competences before starting a test. You can do that by reading the notes below.
If you are unsure of some competence then return to the CPD work if needed – there’s no hurry; this is personal study. The test questions are extensions of the exercises you have completed so the more you study the site in question and its geology the better prepared you will be to cope with the questions asked.
Test for the Basic level
The questions will expect you to be able to:
- Read a simple geological map
- Interpret a simple geological map and stratigraphic succession
- Draw vertical cross sections to display geology
- Create a three-point solution to determine dip and strike from BH locations you have chosen
- Integrate subsurface data with data from geological maps to provide the basis for a conceptual model of the ground on site.
Ground models are inter-disciplinary tools for ground engineering. The exercises therefore cater for:
- Civil Engineers (including geotechnical and geoenvironmental engineers and hydrogeologists) who need to understand how such models are made and thus the sensible limits to their use.
- Geoscientists and geologists who need to be able to justify and verify for the purposes of design, construction and risk, the model they have proposed and to present their model in terms that are useable for geotechnical, geoenvironmental and hydrogeological practice.