Experimental study on rockfall fragmentation: in situ test design and first results

• Main Authors: Gili Ripoll, José Antonio, Ruiz Carulla, Roger, Matas Casado, Gerard, Corominas Dulcet, Jordi, Lantada Zarzosa, Maria de Las Nieves, Núñez Andrés, María Amparo, Mavrouli, Olga Christina, Buill Pozuelo, Felipe, Moya Sánchez, José, Prades Valls, Albert, Moreno, Sjædric
• Format: Publication
• Language: English
• Published: 2016
• Subjects: Enginyeria civil; Geotècnia; Mecànica de roques; Rock mechanics; Àrees temàtiques de la UPC
• ISBN: 1138029882; 9781138029880

Fragmentation is a common feature of rockfalls that exerts a strong influence over the trajectories of the generated blocks, the impact energies and the runout. Real scale rockfall tests have traditionally been designed to evaluate the parameters of rockfall motion. In this contribution we present the results of a set of tests carried out in a limestone quarry that will be used to calibrate and support rockfall propagation models. A total of 56 blocks ranging between 0.2 and 4.8 m3 were dropped from two slope profiles with different morphology and falling height (16.5 and 27.5m total fall). Trajectories of the blocks and velocities were tracked with three high-speed video cameras. Some 43% of the blocks fragmented upon impact with the ground. Most of the blocks were massive limestone although a small percentage displayed a varying amount of finite fissures. The characteristics of the blocks, in particular the size and the Schmidt L hammer rebound were measured before the tests. The results show a lack of correlation between the Schmidt L hammer rebound and the disintegration of the blocks. Finally, it has been observed that the volume (size) distribution of the fragments resulting from the disintegration follow a power law with negative exponents ranging between 0.18 and 0.69. These results are consistent with the observed volume distributions in several natural rockfall events inventoried in limestone environments.