Keywords: geotechnical, soil mechanics, consolidation test, simulation, multimedia, courseware.

This paper will discuss the simulation techniques used to develop CTM, a novel computer based learning package on consolidation. The package includes a video segment in combination with interactive software designed to offer a comprehensive learning medium for students as well as for engineering professionals involved in soil testing. The video offers background information, animations on consolidation, help function, and the test environment. The software simulates the consolidation experiment and poses a number of content oriented multiple-choice questions on the theoretical and professional aspects of the test. To simulate real-life situations a student can choose a soil sample from a location-sensitive map of the Netherlands with options for randomly generated parameters. Test results and individual students performance is recorded for each test session for assessment. The main objective of a standard consolidation test is echoed by CTM: to obtain fundamental consolidation parameters that are used in foundation design. Users of CTM are given instructional tasks in steps after activating the software. The steps are: viewing of the video, instructions, performing the simulated test, calculation of parameters, M-C and calculation type questions, and a design problem based on the measured parameters.

Video segment: The video shows the whole process from taking test samples to the laboratory test environment using self-made captions and animations. The importance of the consolidation test is demonstrated by showing problems that may arise when consolidation is not properly considered. in the design of buildings. The animations are effective in explaining the process of consolidation and the significance of test parameters in practice. To provide optimal video display quality on the computer screen, the video has been digitised in MPEG-I.

Simulation Software: The software part was designed to simulate the entire experiment and to provide plotting and interpolation means of the test results. Databases containing soils data and topical questions together with answers are linked to the package. An assessment report of each individual student performance and a summary test-results report (log-files) are also produced. This provides excellent opportunity for feedback to users otherwise not possible during lecturing. To simulate real testing situations a student can choose a soil sample from a location-sensitive consolidation map of the Netherlands with options for randomly generated sample types and parameters. Each sample is picked up at a certain ground depth from a clay layer of known thickness. The generated samples deviate from each other each time a sample is selected. This, together with per-user randomly posed multiple-choice questions ensure that no two students are subjected to the same test conditions just as two soil technicians are not likely to test the same material. The most intensive part of the software is the generation of the consolidation curves and the manipulation of these curves to derive consolidation parameters and other useful plots (void-ratio-consolidation and rebound curves). Help tool, pop-instructions and formulas for calculations are made accessible at the appropriate points of the simulation to facilitate these tasks.

To write the package we preferred the use of a standard courseware development environment, not programming from scratch in, for example, C of Java. The main 'shell' has been developed in Macromedia Authorware Professional. In the background, we use Microsoft Excel as calculation tool. Real running time for the software part is dependent on the users speed of responding to the instructions and was estimated to take on average 1.5 hours to complete.

Features in CTM and the apparent users satisfaction[1] demonstrate that multimedia computer simulation is an effective tool in replacing and addressing the shortcomings associated with this laboratory test.

1

U. F. A. Karim, "CBL in Soil Mechanics", Proc. Int. conf. on CBL in Science, ISBN 80-7042-144-4, D13, the Netherlands 1998.

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