Theoretical soil mechanics and implement design

Abstract

The fast few decades have seen the steady assimilation of developments in theoretical soil mechanics into the repertoire of analytical techniques for investigating complex soil-machine interactions. This paper attempts to review the contribution made by this knowledge in reinforcing the inherently empirical nature of tillage-implement design and development. The estimation of both quasi-static and dynamic tool forces, the evaluation of soil-disturbance patterns and problems of scouring and vibratory soil cutting have been approached from the point of view of classical soil-mechanics theory. The discussion also shows that the way tillage tools alter the physical environment of plant roots falls within the scope of critical-state soil mechanics and plant biomechanics. It has been shown that failing soil in tension is both a draught and energy-efficient form of loosening soil, and this points to new and challenging directions for the design and development of the next generation of primary-tillage implements.