Emma Britton

Project Title:  An experimental investigation into the arching mechanism in piled embankments

Student Name:  Emma Britton           

Supervisor: Dr. Patrick Naughton

Funding Body:  Strand 1 (Masters Degree funding, transferred to Doctorial register May 2009)

Abstract:

Soil arching is a natural phenomenon which occurs in all granular soils as a result of stress redistribution. In a piled embankment the soft soil between the pile caps settles under the weight of the embankment while the soil block above the pile cap does not thus shear stresses develop in the fill material between the yielding and unyielding zones.

This study investigates the arching mechanism in three sands (two well graded and a uniformly graded) in a 1:3 experimental model. The experimental model imitates a unit cell of a piled embankment, the base of the model consists of 4 plywood blocks each representing ¼ pile cap dimensions and a movable cruciform base which can be lowered either rapidly to represent the formation of a sudden void (sinkhole) or slowly to represent compression of the soft soil on which the embankment is constructed. A raining technique was constructed to allow repeatable sands to be prepared at different relative densities and heights. Instrumentation consisting of 4 no load cells and 3 no linear variable displacement transducers (LVDT’s) recorded the loads on the unyielding pile caps and the base and surface displacements as arching occurred.

Publications/Conferences attended:

The Arching mechanism in piled embankments under Road and Rail Infrastructure. 1st ISSMGE International Conference on Transportation Geotechnics (TC 3), Nottingham, UK, 25-27 August 2008.

An Experimental Investigation of Arching in Piled Embankments. 19th European Young Geotechnical Engineers Conference (19th EYGEC), Gyor, Hungary, September 2008.

An Experimental Investigation of arching in piled embankments and comparison with current design methods. 4th European Geosynthetics Conference (EuroGeo4), Edinburgh, UK, September 2008.

An Experimental Study to determine the location of the Critical Height in Piled Embankments. The first African regional conference on Geosynthetics (GeoAfrica), Cape Town, South Africa, September 2009.

An experimental study to determine the location of the critical height in piled embankments considering the angle of internal friction. The 9th International Conference on Geosynthetics (9th ICG), Guarujá, Brazil, May 2010.

Trap door investigations into the arching phenomena occurring in the granular fill material used in Piled Embankments. Geo –Frontiers 2011, Dallas, Texas. Abstract submitted