The Use of Tactile Sensor Technology for Measuring Soil Stress Distribution

Abstract

The commonly existing methods of evaluating stress distribution in soils rely on the use of buried or surface mounted load cells. These measurements are difficult to perform and are limited in their ability to capture the stress variation. A relatively new technology, which makes use of flexible, grid-based, tactile pressure sensors, allows to measure stresses at a large number of points in proximity to one another, hence providing a realistic normal stress distribution. Their thin (0.1mm) flexible film overcomes the effect of stiffness variation introduced by rigid load cells and thus allows for measurements that better represent the existing stress conditions. The application of the tactile pressure technology to soils requires adaptation and calibration due to its innovative principle of operation. Examples of work carried out over the past ten years are provided. The presented research addresses three subjects in soil mechanics: (i) the effect of grain size on stress distribution measurement along a boundary with a solid surface, (ii) the pressure dip under the sand heap, and (iii) the contact stresses under a rigid strip footing.