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Lecture

Bringing vegetation-based solutions into geotechnical engineering design: how do we make it happen?

Event organised by ICE

Date
14 November 2023
Time

This event has now ended

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Overview

Join us on 14 November as Professor Alessandro Tarantino, professor of experimental geomechanics from the University of Strathclyde, explains how you can get ‘climate-smart’ by adopting a more nature-based approach when building or maintaining earth infrastructure.

Climate change will affect our aging transportation and flood defence earth infrastructure (embankments, cuttings, slopes adjacent to transport corridors). Infiltrating rainwater/floodwater increases pore-water pressure leading to a reduction in soil shear strength eventually triggering slope instability. Dry/wet periods cause shrink/swell behaviour of clayey geostructures and may contribute towards these geostructures reaching the serviceability limit state.

Ground-atmosphere hydraulic interaction is almost always mediated by a vegetated interface. If adequately ‘engineered’, it can be transformed into a valuable climate change adaptation measure for long linear infrastructure subjected to climatic hazard. Vegetation-based solutions are:

  • relatively easy to implement over long distances,
  • ‘climate-smart’ due to plant phenotypic plasticity in a changing climate
  • carbon neutral/negative.

This lecture will present experimental and numerical evidence showing that transpiration-induced suction (hydrological reinforcement) and lateral drainage promoted by the higher hydraulic conductivity of the root zone (hydraulic reinforcement) can considerably affect the stability of slopes. It is also shown that increasing (e.g., due to vegetation growth) or decreasing transpiration (e.g., due to clearing) can lead to excessive deformations of the clayey geostructure.

These processes occur in the Soil-Plant-Atmosphere Continuum (SPAC) and can possibly be amplified or attenuated via the biotic and abiotic manipulation of the SPAC. This is an approach commonly adopted in agriculture and forest management and the event will discuss the lessons we can learn from plant science to develop geotechnical solutions.

Vegetation and soil microbiota live in a complex evolving ecosystem, and post-intervention field monitoring is required to assess the performance of any nature-based adaptation measure (i.e., the observational method is an intrinsic part of ‘designing with nature’). Field monitoring is also key to characterise the SPAC. We cannot bring large ‘representative’ samples of vegetated interface to the laboratory, instead we need to move our laboratory to the field. The lecture will address the challenges and opportunities in the monitoring of the SPAC.

Finally, the lecture will highlight the problem of designing hydrological reinforcement of slopes via a transpiration model designed to be physically-based in order to guide the choice of suitable plant functional traits.

Organised with

The British Geotechnical Association

The British Geotechnical Association

The BGA is the principal association for geotechnical engineers in the United Kingdom and organises a number of high profile events each year.

Programme

19:00 – 19:05

Welcome by Dr Andrew Ridley, managing director, Geotechnical Observations Ltd and chair, British Geotechnical Association

19:05 – 20:00

Keynote address by Professor Alessandro Tarantino, professor of experimental geomechanics, deputy head of department and director of research and teaching laboratories, University of Strathclyde

20:00 – 20:25

Q&A session

20:25 – 20:30

Closing remarks by Dr Andrew Ridley

Speakers

Dr Andrew Ridley

Dr Andrew Ridley

Geotechnical Observations Ltd

managing director & owner

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Dr Andrew Ridley

Dr Andrew Ridley is Chair of the British Geotechnical Association and managing director of Geotechnical Observations Limited which he founded in 2000.

With over 40 years’ experience within the geotechnical sector of the civil engineering industry, he is known for his work on the measurement of soil suction (in situ and laboratory) for which he received a PhD from Imperial College London.

Andrew is currently the UK's representative on ISO TC182 WG2, which is writing international standards for geotechnical monitoring, a member of the British National Committee for standards in geotechnics B_526_3, Chair of ISSMGE TC220 Field Monitoring in Geomechanics and was Chair of the local organising committee for the 11th International Symposium on Field Monitoring in Geomechanics held at Imperial College London in September 2022.

In addition, Andrew was a member of the Steering Committee for CIRIA 550 Infrastructure Embankments – Condition Appraisal and Remedial Treatment, on the Editorial Panel of Geotechnical Engineering (Proceedings of the Institution of Civil Engineers) from 1998 to 2001 and was a member of the sub-committee to the Advisory Panel of Géotechnique for the 2011 Symposium in Print on Partial Saturation in Compacted Soils.

Prof. Alessandro Tarantino

Prof. Alessandro Tarantino

University of Strathclyde

professor of experimental geomechanics

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Prof. Alessandro Tarantino

Professor Tarantino joined the University of Strathclyde in 2010 as professor of experimental geomechanics to establish a research group in geomechanics and geohydraulics specialised in laboratory and field investigation of multiphase geomaterials.

The common denominator of his research is the presence of at least two fluid phases (liquid and gas) in the medium pore space. Under these conditions, different physical processes with high level of coupling (liquid flow, vapour flow, heat transfer, and solid matrix deformation) control the hydraulic and mechanical behaviour of the porous medium, which is therefore relatively complex to investigate and model.

In civil and environmental engineering, multiphase (unsaturated) porous media are typically encountered in the upper portion of the soil profile, between the ground surface and the ground water table/phreatic surface. Processes occurring in this zone are therefore the focus of my research, and includes rainwater infiltration, groundwater recharge, pollutant transport, soil shrinkage and heave, surface cracking, soil subsidence, and subsurface water flow and runoff (i.e. flood formation), and shallow landslides. Most of these processes have an interaction with the atmosphere and are therefore strongly affected by climate changes.

Multiphase (unsaturated) porous media are also encountered in several geo-infrastructures, including road, railway and flood embankments, dams, and tunnels where mechanical and hydraulic response (stability, deformation, hydraulic conductivity) is controlled by the interaction of the ground with the atmosphere.

For more information please contact:

Shelly-Ann Russell