A new artificial root system to simulate the effects of transpiration-induced suction and root reinforcement

Vegetation is increasingly recognised as an eco-friendly method for slope stabilisation, through mechanical root reinforcement and transpiration-induced soil suction. Several centrifuge tests have been carried out to investigate failure mechanism of slopes mechanically reinforced by roots. However, the effects of transpiration-induced soil suction were ignored, and hence any of its contribution to stability enhancement is not well-understood. This paper aims to develop and verify a new artificial root that is capable of simulating both the effects of transpiration-induced suction and mechanical reinforcement for physical modelling, including centrifuge at high-g. The artificial root was made of a high air-entry value (AEV) porous filter and supplied with vacuum pressures. The function of the porous filter is to maintain hydraulic gradient between soil and the system. Any reduction of soil moisture due to applied vacuum hence induces suction. In order to verify this newly developed system, mechanical properties and suction distribution influenced by the new artificial root and selected living tree were tested and compared in an atmospheric controlled room. The comparisons of test results showed that the suction distributions induced by the artificial root and the living tree were reasonably close, during both transpiration and a rainfall event.