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A large-scale experimental investigation was carried out on the specimen of reinforced concrete (RC) wall which was fitted with a gabion cushion cover and was fixed at its base. The objective of the investigation was to determine the flexural capacity of the wall when subjected to the impact of a fallen boulder. The RC wall specimen which was 1.5 m tall, 3 m wide and 0.23 m thick was cast on top of a 0.5 m thick RC base slab which was in turn anchored rigidly onto a 1 m thick strong floor of the laboratory. A steel object (the impactor) weighing 280 kg was released from a range of pre-determined heights to deliver two impact energy levels: 1.37 kJ and 3.85 kJ. The layer of gabion which was used as cushion cover to protect the RC wall was 300 mm, 500 mm or 1000 mm thick. The experiment was carried out in a fully controlled laboratory environment involving over 60 pieces of instrumentation to record the behaviour of the specimen responding to the impact actions. In this paper, details of the impact experiments including its setup will be presented along with key observations and measurements. It was found that the impact response behaviour of the stem wall varied significantly with the thickness of the gabion cushion, and that localised failure of concrete was completely eliminated even with a 300 mm thick gabion cushion.