Out-of-plane analysis of dry-stone walls using a pseudo-static experimental and numerical approach in natural-scale specimens

On the slopes of some Andean cities, the population is at high seismic risk due to their informal homes, built without technical advice, based on non-compacted backfill, and supported by dry stone retaining walls (pircas). In this work, we aimed to evaluate the out-of-plane performance of the typical retaining walls of the city of Lima, Peru, located on the slopes of the central Andes. In this first study, the effect of the backfill has not been considered because only the behavior of the wall was studied. Three walls of height 1 m and three of height 1.5 m were built and tested. The construction was carried out by local workers, following their traditional practices, and tests were carried out on a tilting platform to generate out-of-plane gravity loads. Delamination and overturning were the most frequent types of failure. From the experimental tests, we found that the average ultimate resistance to displacement was 31 % and 24 % of the weight for the 1 m and 1.5 m walls, respectively. The discrete element method was used for the numerical models, and the contact parameters of stiffness and friction angle corresponding to the Coulomb model were calibrated using the experimental results. The effects on the mechanical behavior of the use of through stones and overlaps between wall elements were studied. It was concluded that the pircas could be improved to a limited extent with better construction practices, and further studies are therefore required with the aim of improving current construction practices. In a later study, the interaction between the wall and the backfill will be studied numerically and experimentally.