Agent-based modeling and simulation of earthmoving operations

Discrete-Event Simulation (DES) models are constructed from sequential duration-based activities. DES is used in modeling several construction operations including earthmoving. Current earthmoving models cannot accommodate equipment units with different specifications performing the same task. In addition, activity durations are calculated based on primitive methods such as interpolating existing durations of similar activities in previous projects. Finally, model elements behave in a predetermined manner, ignoring special operational real-life scenarios that occur due to resource constraints. These limitations often lead to inaccuracies in calculating productivity and equipment utilization. This paper applies Agent-Based Modeling and Simulation (ABMS) as an effective bottom-up tool to modeling earthmoving operations. An Agent-Based (AB) earthmoving model consisting of smart, adaptive agents is developed. Each agent is assigned a state chart and a set of static and dynamic properties (attributes and variables) to direct its interactions with the environment and with other agents. This framework proves how modeling earthmoving from the agent's prospective and basing agents' interactions on their properties allow for modeling equipment units with different specifications performing the same task (e.g. trucks of different capacities), as well as for an accurate representation of activity durations, resource handling and resource constraint scenarios. A Java-based application named Agent-Based Simulator for Earthmoving Operations (ABSEMO) is developed as an implementation of the proposed model. ABSEMO will be helpful to contractors in planning earthmoving operations according to the AB approach. A real-life case study of a riverbed excavation in a dam construction project is simulated using ABSEMO, and the results are compared with those obtained from existing simulation models to verify ABSEMO's logic. A percentage difference of 0.42% from the existing results is obtained, indicating that the model's flow of resources is indeed accurate.