A Laboratory-Scale Evaluation of Smart Pebble Sensors Embedded in Geomaterials

Area of Science:

• Geotechnical Engineering
• Materials Science
• Sensor Technology

Background:

• Geomaterial deformation monitoring is crucial for infrastructure stability.
• Existing methods for measuring internal deformations can be limited.
• Mechanically stabilized aggregates with geogrids present complex stress-strain behaviors.

Purpose of the Study:

• To introduce and validate the 'Smart Pebble' sensor for measuring deformations in unbound aggregates stabilized with geogrids.
• To assess the Smart Pebble's ability to track resilient behavior and local stiffness enhancements.
• To compare Smart Pebble measurements with traditional bender element sensor data.

Main Methods:

• Integrating Smart Pebble sensors into triaxial test specimens of geogrid-stabilized unbound aggregates.
• Utilizing an aggregate particle/position tracking algorithm with Kalman filtering for sensor data processing.
• Simultaneously recording resilient deformations and shear wave velocities using bender elements.
• Analyzing linear vertical acceleration trends for geomaterial configuration and stress state assessment.

Main Results:

• Smart Pebbles successfully tracked position coordinates and indicated geomaterial configuration and stress states.
• Resilient deformations measured by Smart Pebbles showed close agreement with bender element sensor data.
• Smart Pebbles effectively quantified local stiffness enhancement in the geogrid-stabilized specimen.
• The sensors demonstrated the ability to describe the resilient behavior of aggregate materials under repeated loading.

Conclusions:

• The Smart Pebble sensor presents a viable novel approach for monitoring internal deformations in geomaterials.
• The sensor technology accurately captures the resilient behavior of geogrid-stabilized aggregates.
• Smart Pebbles offer a promising tool for enhancing geotechnical engineering analysis and design.