Small-scale Geotechnical Testing Using a Six-axis Robot

Abstract

Single-gravity (1-g) small-scale testing is a widely used method to investigate geomechanics problems that involve the interactions between soils and objects (e.g., structures or machine parts). This letter presents a new approach for performing 1-g model tests where a six-axis industrial robot functions as a versatile actuator capable of moving objects along virtually arbitrary trajectories, while simultaneously tracking multiple components of force and moment acting on the objects. A performance evaluation confirms that the robot's motion control and force measurement are sufficiently accurate for geotechnical model tests. This assessment is completed through two benchmarking exercises: (1) determining the failure envelope of a strip foundation subjected to combined loading and (2) quantifying the force-displacement history for the soil cutting process (e.g., for applications in soil-machine interaction).