Abstract
A key problem experienced when soils liquefy during earthquakes is that gently sloping ground can translate downslope. Most recently, this lateral spreading was seen to affect large portions of coastline around Palu Bay in the 28 September 2018 Indonesia earthquake. Soil observed to experience lateral spreading frequently contains plant roots that in principle should have a reinforcing effect on the soil. However, field data is difficult to interpret due to the many uncontrollable variables, so there has not previously been an attempt to quantify roots effects on lateral spreading. Physical modelling offers an opportunity to test soil in real site conditions with controlled variables (soils, slopes, stratification etc.). In this study, a small scale model with the potential to undergo lateral spreading is created and tested on the geotechnical centrifuge. Considerations of how the model could exhibit lateral spreading without boundary interaction, and how both fibrous roots (like grass) and more woody roots (like a shrub) could be modelled in a
small scale model, are discussed. The model is shown to recreate a lateral spread during centrifuge testing when the soil contains no roots. When tested in moderate-sized earthquake events, the lateral displacement was reduced by ~60% by fibrous root analogues and 70% by woody root analogues. However, in stronger events where liquefaction occurred to greater depths, then the near-surface roots offered less resistance to displacement. These results indicate that without roots, spreading could be worse, but the roots alone may not be enough to prevent damage completely, particularly in larger earthquakes.
small scale model, are discussed. The model is shown to recreate a lateral spread during centrifuge testing when the soil contains no roots. When tested in moderate-sized earthquake events, the lateral displacement was reduced by ~60% by fibrous root analogues and 70% by woody root analogues. However, in stronger events where liquefaction occurred to greater depths, then the near-surface roots offered less resistance to displacement. These results indicate that without roots, spreading could be worse, but the roots alone may not be enough to prevent damage completely, particularly in larger earthquakes.
Original language | English |
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Title of host publication | SECED 2019 Proceedings |
Place of Publication | United Kingdom |
Publisher | Society for Earthquake and Civil Engineering Dynamics |
Pages | 1-9 |
Number of pages | 9 |
Publication status | Published - 29 Sept 2019 |
Event | SECED 2019 Conference: Earthquake risk and engineering towards a resilient world - University of Greenwich, London, United Kingdom Duration: 9 Sept 2019 → 10 Sept 2019 https://www.seced.org.uk/index.php/2019-home |
Conference
Conference | SECED 2019 Conference |
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Country/Territory | United Kingdom |
City | London |
Period | 9/09/19 → 10/09/19 |
Internet address |