Re-assessing a soil nailing design in heavily weathered granite after a strong earthquake

Abstract

Soil nailing is increasingly adopted in potentially unstable slopes and steep excavations in Concepción, Chile. The paper presents a study of soil nailing design and construction in Maicillo, a heavily weathered granite. The stability of the soil nailed wall was analysed using a limit equilibrium block method. The lowest factor of safety was obtained when the nailed wall was 8 m high but without the bottom row of nails. This was followed by the global seismic case using an acceleration factor k h= 0.15. The occurrence of a strong earthquake (magnitude 8.8) 2 weeks after completion of the projected allowed a re-assessment of the soil nailing design. Despite registering a maximum acceleration of 0.63 g near the project site, the nailed wall did not present any damage, probably due to the use of undrained shear strength parameters