ABSTRACT:

When conducting an experiment in which quantitative measurements of displacements are required it is important that these are obtained with the highest accuracy possible. Often these experiments may require data to be collected remotely. For example, centrifuge model studies where the experiment cannot be accessed for direct measurement or the long term monitoring of slopes and structures where regular measurements are required. The power of modern computers and the development of software means that using digital images to monitor displacements accurately has become economically viable. This paper presents the development of an automated image analysis system using the software package MATLAB and KODAK digital cameras, which has been tested using centrifuge experiments, and has many further applications to geotechnical problems.

INTRODUCTION

When conducting an experiment in which quantitative measurements of displacements are required it is important that they are obtained to a high accuracy. Often these experiments may require data to be collected remotely. For example, centrifuge model studies where the experiment cannot be accessed for direct measurement or the long term monitoring of slopes and structures where regular measurements are required. The nature of centrifuge modelling precludes direct measurement of displacements during the test procedure. There are various methods to achieve this remotely, such as using displacement transducers and a data logger to monitor deformations. However, this only provides information of surface movements, and is limited to a few discrete points. Geotechnical engineers are also interested in displacements and strains developing at depth. An effective technique that can provide surface and deep-seated displacements is image analysis. Figure 1 shows a typical plane strain centrifuge model in a strong box (Jones 1999). On the side face of the model there is a regular pattern of markers, which are assumed to have good contact with the soil.

This content is only available via PDF.
You can access this article if you purchase or spend a download.