Stability of granite drystone masonry retaining walls: II. Relevant parameters and analytical and numerical studies of real walls

This paper applies the analytical limit-equilibrium technique described in the accompanying Part I of this article to the design of granite drystone masonry retaining walls. Particular attention has been paid to estimating relevant parameters for the materials used. The friction angle between the stone blocks was studied by means of full-scale tests, and an empirical method was used to estimate the backfill strength properties. The dip of the base of the part of the wall tending to overturn was also studied. The technique was tested by back-analysing three wall failures, and was compared with numerical results from the UDEC code, suggested as an appropriate approach for assessing analytical results. Analytical factor of safety results for the design of a 20 m-high wall compared well with the numerical approach used in combination with the shear strength reduction technique. The results confirm the suitability of the limit-equilibrium approach for analysing these traditional, cost-effective and environmentally friendly structures.