Abstract Various mechanical excavators have been used for rock cutting. The cutting drum of an excavation machine normally consists of a large number of cutting picks. Accurate calculation of cutting force on individual picks is important to machine design and control. In rock cutting, cuts between picks can interact with each other. If a cutting force model has not considered the cutting interactions properly, the forces predicted by this model could significantly overestimate the “actual” force. On the other hand, many empirical cutting force models are developed based on laboratory test results using small Depth Of Cut (DOC) without significant cutting interactions. How to correctly applying these models to predict cutting force with large DOC is a challenge. This paper presents an approach for quantitatively analyzing the influences of cutting interactions on cutting force of a pick. The research results can help optimally select excavation machines and/or cutterhead motors, and optimize pick and drum design.