Drystone retaining walls: Ductile engineering structures with tensile strength

Abstract

Drystone retaining walls are sustainable engineering structures constructed with locally obtained natural stone. They were commonly built with very slender profiles compared with modern massmasonry structures, leading to a common belief among engineers that they have very low margins of safety. These structures remain critical to the transport infrastructure in many parts of the world, and have proven to be very durable, yet very few new drystone retaining walls are built, and walls which do fail are usually replaced with concrete constructions. We show that these walls are ductile even though their components are brittle, and in having tensile strength through the interlocking of their stones, even though they are assembled without any cohesive material such as mortar. These properties are critical to a proper understanding of their behaviour and durability. Full-scale testing of five drystone retaining walls has shown that bulging, most commonly regarded as a sign of incipient failure, begins as a ductile adaptation of the geometry to the loads imposed on it. Localised bulging can be a consequence of small defects in construction or foundation conditions, or concentrated loading, and may be sustained indefinitely in a wall which is in general wellconstructed. These insights into the behaviour of walls allow the design of new walls which use materials efficiently, and enable existing walls to be kept in service, and may inspire new ways of achieving ductility in engineering materials.

Implications of climate change for railway infrastructure

“…Upgrading drainage, rock bolting/anchoring, regrouting (McCombie et al, 2012; O'Reilly & Perry, 2008)…”

Assessing the Three-Dimensional Behaviour of Dry Stone Retaining Walls by Full-Scale Experiments

“…Only two full-scale experimental campaigns have been performed in order to assess the 3D behaviour of dry stone retaining walls. The first one took place at the University of Bath (UK), comprising 5 tests on 2.5 m high walls (McCombie et al, 2012;Mundell et al, 2010). Walls were built in limestone or slate, backfilled with crushed gravel, and loaded with a hydraulic jack applied on a plate placed on the surface of the backfill.…”

“…Distinct element modelling has been developed to understand the bulging pathologies in existing walls (Claxton, Hart, McCombie, and Walker, 2005;Harkness, Powrie, Zhang, Brady, and O'Reilly, 2000;Powrie, Harkness, Zhang, and Bush, 2002;Walker, McCombie, and Claxton, 2007), based on the experimental data from (Burgoyne, 1853). On the other hand, limit equilibrium (Mundell, McCombie, Bailey, Heath, and Walker, 2009;Villemus, Morel, and Boutin, 2007), yield design Garnier, 2010, 2013), and distinct element (Oetomo, Vincens, Dedecker, and Morel, 2015) analyses have been performed to assess the stability of new or existing structures, calibrated and validated on dedicated full-scale tests (Colas et al, 2010;McCombie, Mundell, Heath, and Walker, 2012;Mundell, McCombie, Heath, Harkness, and Walker, 2010;Villemus et al, 2007). Numerical and theoretical developments have been exclusively performed in 2D on wall cross-sections.…”

“…Numerical and theoretical developments have been exclusively performed in 2D on wall cross-sections. Only one full-scale (McCombie et al, 2012;Mundell et al, 2010) and one recent scale-down (Quezada, Vincens, Mouterde, and Morel, 2016) experimental campaign have been performed in 3D, to assess the effect of traffic on dry stone walls.…”

Dynamic behaviour of drystone retaining walls: shaking table scaled-down tests

“…In other European countries, the behaviour of slope DSRWs is also a new field of research (Walker et al, 2007;Alejano, Veiga, Gómez-Márquez, & Taboada, 2012;Alejano, Veiga, Taboada, & Díez-Farto, 2012;Pulatsu et al, 2020). In addition, other experimental (Mundell et al, 2009(Mundell et al, , 2010McCombie et al, 2012;Le et al, 2019), analytical (Le et al, 2016) and numerical (Quezada et al, 2016) studies have been carried out on 3D failure of DSRWs induced by a concentrated load on backfill top.…”