Experimental investigation of the pull-out resistance of simplified root system architecture models in dry sand

The interaction of plant roots with the soil is of importance for the mechanical and hydraulic behaviour of soils world wide. Due to mechanical reinforcement by a living root network, soil is strengthened to resist erosive forces caused by rain or wind and also by external loads, either natural or man-made. Furthermore, living roots influence the soil moisture distribution due to their effect on soil suction which is driven by the plants’ metabolism and evapotranspiration in the canopy of leaves, also causing cooling effects. All those effects, many of which are still poorly understood, make rooted soils an interesting topic for soil science, geomechanics, and geotechnical engineering. Rooted soil has developed into a relevant research topic in recent years because technical designs can be derived from nature’s plan within the framework of bio-inspired (geotechnical) engineering, also known as bionics. Within the scope of this contribution, we present experiments on the mechanical interaction of simplified tree root models in order to find new designs for nature-inspired foundation systems. Results of a series of pull-out tests on root models with varying geometries indicate that the pull-out resistance of the studied “root piles” can be much increased as compared to a standard cylindrical tension pile.