Numerical and experimental pseudo-static study on block arrangement effects in traditional dry-stone walls for out-of-plane mechanical behavior evaluation

In Lima's slopes, the absence of urban planning has led to housing built on backfills contained by traditional dry-stone retaining walls, called “pircas,” which pose high seismic risk. A previous study [1], which combined numerical and experimental analyses, evaluated pircas through pseudo-static tests that reflected common construction methods in Lima's eastern region. One recommendation from that study was to explore effective stone arrangements to enhance the seismic performance of pircas. Consequently, this study aims to examine how the construction process, particularly the arrangement of stones, impacts the out-of-plane behavior of pircas. The research focuses on identifying construction-feasible configurations that can effectively improve their seismic performance. For this purpose, natural-scale pseudo-static experimental studies and numerical modeling using the Discrete Element Method (DEM) were carried out. The experimental campaign consisted of nine pseudo-static tests on different wall arrangements. The pseudo-static numerical study included seventy wall arrangements. The geometry of the blocks was simplified to eliminate this component from the analysis, which focused on the arrangement of the wall. The numerical and experimental results showed the same trend. The study has demonstrated that the current construction technique can be significantly improved by regularly incorporating through-stones—tie stones that pass through the entire cross-section of the wall—and considering a cross-section with overlap. This approach leads to an increase of up to 50% in lateral strength compared to current practices, verifying the effectiveness of through-stones. The study does not intend to endorse the use of pirca for urban habitation in high seismic sectors. However, these traditional walls can be recommended for slope stability, environmental mitigation, urban agriculture, and protection of natural areas.