Small-scale modelling of plant root systems using 3D printing, with applications to investigate the role of vegetation on earthquake-induced landslides

Abstract

Small-scale modelling of plant root systems using 3D printing, with applications to investigate the role of vegetation on earthquake-induced landslides.

Newmark sliding block model for predicting the seismic performance of vegetated slopes

“…The impacts of vegetation on seismic performance of slopes subjected to earthquake ground motions are generally overlooked in preliminary design. As observed by recent physical modelling studies [7][8][9], vegetation could highly improve the seismic performance of slopes (in terms of crest settlement) especially for the case of slopes of modest height (e.g. small embankments).…”

“…The sand was pluviated in air around suspended model root clusters with realistic 3-D geometry that were fabricated at 1:10 and 1:30 scales using a Stratesys Inc. uPrint SE Acrylonitrile Butadiene Styrene (ABS) prototyper (also known as a 3-D printer)following the procedures outlined in[9], in each case penetrating into the slope to the same rooting depth (1.5 m). The ABS plastic root analogues were validated to be highly representative of the mechanical behaviour of real roots (in terms of Young's Modulus and tensile strength) after a series of uniaxial tension and bending tests, reported in[7],[9]. In the out-of-plane direction, model root clusters were uniformly distributed at a spacing of 1.4 m. The models were each subjected to eight successive earthquake motions, comprising three different records with distinct peak ground acceleration (PGA), duration and frequency content.…”

“…) due to the presence of the roots in this particular test and is incorporated by multiplying the input motion by a factor of 0.85 to obtain a new input motion[9]; case (d) considers the combined effects of case (b) and case (c). It can clearly be seen that case (a) without consideration of the acceleration reduction effect highly under-estimates the contribution of the roots in reducing the slope crest deformation response.…”

Numerical techniques for fast generation of large discrete-element models

“…Centrifuge lab tests are widely used in geomechanics and, by imposing an increased 'gravitational' acceleration to the physical model, it is possible to reproduce in the lab self-weight stress profiles comparable to the ones in the field. In this way, it possible to obtain accurate data to help solve complex geotechnical problems (Bolton et al, 1999;White and Lehane, 2004;Liang et al, 2017). Centrifuge tests however are expensive and time consuming, so accurate DEM models may be useful in helping to design the experiments themselves.…”

Physical modelling of structural and biological soil reinforcement

“…For simplicity, the model uses just four different root diameters. Further information about the detailed design process and the shear strength contribution that the model can make within rooted soil can be found in Liang et al (2017). Figure 16 shows a different model for a Pine (Pinus pinaster) root system which has a greater amount of lateral rooting material.…”