Construction, management and maintenance of embankments used for road and rail infrastructure: implications of weather induced pore water pressures

Abstract

S. (2014) 'Construction, management and maintenance of embankments used for road and rail infrastructure : implications of weather induced pore water pressures.', Acta geotechnica., 9 (5).pp. 799-816. Further information on publisher's website:http://dx.doi.org/10.1007/s11440-014-0324-1Publisher's copyright statement:The nal publication is available at Springer via http://dx.doi.org/10.1007/s11440-014-0324-1Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. beneath the shoulders of the embankment in response to weather events that were imposed upon its surface by both natural and artificial means. Significant differences were observed in pore water pressure behaviour across the embankment, which were influenced by compaction level, aspect and presence of a granular capping material on the crest. Permeability was also observed to vary across the embankment both spatially and with depth, and temporally, being dependent on degree of saturation and macro-scale effects, particularly within a 'near surface zone'. A conceptual model of an engineered embankment is proposed which encapsulates the above behaviour so as to assist in the modelling and monitoring of road and rail embankments.

Challenges in monitoring and managing engineered slopes in a changing climate

“…It is well understood that increasing ground water decreases soil strength and can lead to swelling of some clay soils [4] and that conversely drying increases soil strength but causes shrinkage and desiccation cracking [5]. These moisture-driven changes have the potential to increase the incidence of failure across a range of earth structures [6,2] affecting road and rail networks. Whilst the magnitude of these impacts is not yet fully understood, engineers and asset managers require reliable and cost effective systems to monitor the condition of these assets and direct maintenance activities at the most vulnerable parts of the network.…”

“…If ERT is to fulfil its potential in geotechnical monitoring then it is necessary to understand how soil suction and resistivity interact when subjected to seasonally varying water content, in order to be able to interpret geophysical information gathered from electrical resistivity tomography arrays. To this end, an experimental programme integrating field monitoring and multi-scale laboratory tests has been undertaken on a Glacial Till clay material obtained from a full-scale test embankment in Northumberland, United Kingdom, which forms part of the BIONICS field research project [2,6]. The experiments have been designed to establish the relationships between soil water content, resistivity and pore water pressure, with a particular focus on whether these relationships remain constant over time.…”

“…Major transport infrastructure asset managers have progressed investigations into geotechnical risk through the use of morphological and geotechnical characteristics and a variety of research consortia collaborate with asset managers to progress the science underpinning management, maintenance and intervention strategies [1,2,8,9,14,41]. Coupling system with near-future weather data (e.g.…”

“…Climate change projections across Europe are varied and there will be important regional differences in how this is manifested and how this will impact on the performance of engineered slopes for transport infrastructure. One of the important regional examples that requires further investigation includes an increased likelihood of summer drought leading to drying/cracking of soil which will in turn lead to increased macro permeability and hence more rapid ingress of water during extreme precipitation) [1,2].…”

Soil water retention behaviour for an instrumented embankment

“…Glendinning et al [12] describe field measurements of suction and water content measured in the BIONICS embankment. Suctions were measured using MPS-1 dielectric water potential sensors produced by Decagon Ltd.…”