Geotechnical Laboratory Testing Symposium

Geolabs, Garston, Watford, Building 19

Day 1 will concentrate on the more commonly used tests and will look at what type of samples are required, how the test is performed and the results calculated. Some time will be spent on looking at the interpretation of the test results and some of the commonly held misconceptions.

This very full day will include the practicalities of the tests, how to decide what testing is required and what you need to look for in the results. During the day visits will be made to the various parts of the Geolabs facilities to look at the test equipment and testing in action in a commercial environment.

Day 1 is an absolute must for anyone who is responsible for obtaining samples, procuring or designing investigations, The day will include much of the theory which has either been forgotten or is taken for granted in accepting the results the computer produces.
After day one we would expect delegates to have much more confidence in the testing they schedule and be able to decide what is required to produce the results they will be relying on for their design.

The day will culminate with a brief overview of the effect of the Eurocode on testing and will introduce the concept of more specialist testing which will form the programme on Day 2.

Topics on the agenda will include:

Classification testing

• the importance of moisture content
• Plasticity index - understanding the parameters
• Particle size - limitations of the tests

Earthworks testing

• Compaction theory
• The CBR - what does this measure?
• The MCV - understand what is used for.
• Soil Stabilisation.

Understanding Strength testing

• Triaxial and its many variants
• Quick undrained
• Basics of effective stress testing
• Total stress vs effective stress
• Drained vs Undrained
• Misconceptions

Shear box testing

• Conventional shear box
• Ring shear
• Other Tests
• Oedometer testing understanding the results of the test
• Permeability tests – it many variants which one do we need?

Day 2

The second day will focus on the more sophisticated/specialist tests which are becoming readily available to the industry and commonplace in the more specialist commercial laboratories. These often provide the parameters which computer solutions require and until recently have been taken from text books.

Topics to be discussed will include:

What parameters do the tests give us?
Why should we do them?
When should we do them.?

These topics will be presented by leaders in the field and include Dr Lianne Gasparre , Dr Mike Rattley, Dr John Powell, Dr Andrew Ridley, Karl Snelling

They will include the more advanced aspects of the triaxial test. These tests provide the parameters needed for many of our design calculations and computer analysis, however do you know what can be actually achieved, and what the results mean. How are the results controlled by the quality of the sample obtained for testing.

• Stress path
• Small strain, axial and radial small Strain measurements.

Through the day you will be able to witness these tests being set up and will get an appreciation of the skill required in just setting up the test. You be able to see the test being run and the data measured.

• Bender element. - A few years ago this was only found in universities now it is appearing in the larger commercial laboratories
• CIU or CAU - which variant of the Triaxial test do you need for your application?
• Extension vs compression - which will give a more realistic result.

Other tests and their instrumentation will also be presented – these are all now found in the commercial laboratories and provide essential parameters for the design of structures both offshore and onshore these include:-

• Simple shear
• Constant rate of strain oedometer
• Cyclic loading
• Resonant column
• Soil suctions - is this the way to determine if we have a class 1 sample

During day two tests which have yet to appear in the commercial environment such as hollow cylinder will also be discussed.

When utilising tests which measure to higher accuracy it is essential to consider the quality of the sample being tested, examples will be given of the effect on results. The various techniques and their limitations will be considered. There will also be ample time for discussion.

Similar to day one there will be a visit to the small strain and bender element testing facilities within the Geolabs complex. This will include a demonstration of a sample preparation for an advanced test with various configurations of equipment

Attendees on day 2 will gain a working appreciation of what can be expected from these more advanced tests and how they can produce quality results for use in the design process. The day will highlight that in order to produce good results it is necessary to consider the quality of the investigation.