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Details of Grant 

EPSRC Reference: EP/M015483/1
Title: Rapid Prototyping of High Strength Geosynthetic Interfaces
Principal Investigator: Fowmes, Dr G
Other Investigators:
Researcher Co-Investigators:
Project Partners:
Geofabrics Limited Golder Associates (International) International Geosynthetics Society
URS Infrastructure & Environment UK Ltd
Department: Civil and Building Engineering
Organisation: Loughborough University
Scheme: First Grant - Revised 2009
Starts: 01 May 2015 Ends: 31 July 2016 Value (£): 99,434
EPSRC Research Topic Classifications:
Ground Engineering
EPSRC Industrial Sector Classifications:
Manufacturing Construction
Related Grants:
Panel History:
Panel DatePanel NameOutcome
03 Dec 2014 Engineering Prioritisation Panel Meeting 3rd December 2014 Announced
Summary on Grant Application Form
Construction using geosynthetics offer savings both in terms of cost and embodied carbon. However, their application is limited by poor understanding of geosynthetic soil interaction, resulting in at best over conservative designs and at worst failures resulting in uncontrolled contamination and loss of life. This fifteen month project will use digital imaging and rapid prototyping to create higher strength interaction between geosynthetics and adjacent materials, allowing steeper, higher and safer slopes to be constructed, thus facilitating sustainable construction using these materials.

In barrier systems, geomembranes are typically placed, as part of multilayer systems, over low permeability clay to create a composite barrier benefiting from the low permeability of the geomembrane and attenuation properties of the clay. The geomembrane is then overlain by a geotextile or sand to project it from puncture and damage from the overlying material. This project will allow design of geomembrane surfaces for interaction with these adjacent materials. The designed interfaces will have greater peak strength and allow designers to understand and specify the characteristics of interface shear strength beyond simply the height of the surface texturing (asperity height). In practical terms it will allow higher and steeper slopes when using geomembrane barrier systems, offering improved project profitability and safer use across all applications.

The upper bound interface shear strength is controlled by the material adjacent to it. For a geosynthetic-soil interface this is the strength of the soil. For a geomembrane-geotextile interface the maximum strength will be controlled by the internal bond and fibre strength of the geotextile. The role of the texturing is to transfer the stresses into the adjacent material. The "one size fits all" approach of 0.25mm asperity results in the same texturing being used for interactions with fine grained soils, coarse grained soils and geotextiles and also at low and high confining stresses.

The main gaps in knowledge to be addressed are as follows:

1. What are the physical mechanisms that develop peak strength in geomembrane-soil and geomembrane-geosynthetic interfaces?

2. How do these mechanisms differ for interactions with geotextile, coarse grained soil and fine grained soils?

3. Can the nature of the geomembrane surface be designed to better transfer and distribute load, to produce an interface with higher strength?

The project will use scanning electron and optical microscopes to study material interaction to determine how peak strength is mobilised and from these studies produce CAD models of high strength interfaces. The CAD models shall be converted into physical models through 3D printing allowing their interaction with soils and geotextiles to be observed and quantified.

The work will allow design of geomembrane surfaces for interaction with typically used materials. The designed interfaces will have greater peak strength and allow designers to understand and specify the characteristics of interface shear strength beyond simply asperity height. In practical terms it will allow higher and steeper slopes when using geomembrane barrier systems offering improved project profitability.

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Organisation Website: http://www.lboro.ac.uk