Experimental and Theoretical Studies to Improve Rock Fall Analysis and Protection Work Design

Giani, G. P.; Giacomini, A.; Migliazza, M.; Segalini, Andrea

doi:10.1007/s00603-004-0027-2

Cited by 134 publications

(91 citation statements)

References 5 publications

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“…Furthermore, simulations show that rebound trajectories require higher values of the two coefficients of restitution for dolomitic-limestone than for pyroclastic soil (0.48 vs. 0.25 and 0.73 vs. 0.55, respectively) to reproduce the rebound sequence observed in the study area. These values are generally consistent with those suggested in the scientific literature (Richards, 1988;Chau et al, 2002;Giani et al, 2004), demonstrating that boulders bounced on the soil slope with greater energy loss than on the dolomitic-limestone cliff.…”

Section: Resultssupporting

confidence: 89%

Rockfall-induced impact force causing a debris flow on a volcanoclastic soil slope: a case study in southern Italy

Budetta

2010

Nat. Hazards Earth Syst. Sci.

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Abstract. On 10 January 2003, a rockfall of approximately 10 m 3 affected a cliff some 25 m high located along the northern slopes of Mt. St. Angelo (Nocera Inferiore, province of Salerno) in the southern Italian region of Campania. The impact of boulders on the lower sector of the slope, along which detrital-pyroclastic soils outcrop, triggered a small channelled debris flow of about 500 m 3 . Fortunately, no damage nor victims resulted from the landslide. Several marks of the impacts were observed at the cliff toe and outside the collapsed area, and the volumes of some fallen boulders were subsequently measured. By means of in-situ surveys, it was possible to reconstruct the cliff's geo-structural layout in detail. A rockfall back-analysis was subsequently performed along seven critical profiles of the entire slope (surface area of about 4000 m 2 ). The results of this numerical modelling using the lumped-mass method were then used to map the kinetic iso-energy curves. In the triggering area of the debris flow, for a falling boulder of 1 m 3 , the mean kinetic energy was estimated at 120 kJ, this value being equivalent to an impact force, on an inclined surface, of some 800 kN. After landing, due to the locally high slope gradient (about 45 • ), and low angle of trajectory at impact (about 23 • ), some boulders slid down the slope as far as the endpoints. The maximum depth of penetration into the ground by a sliding block was estimated at about 16 cm. Very likely, owing to the high impact force of boulders on the saturated soil slope outcropping at the cliff base, the debris flow was triggered under undrained loading conditions. Initial failure was characterized by a translational slide involving a limited, almost elliptical area where the pyroclastic cover shows greater thickness in comparison with the surrounding areas.

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Section: Resultssupporting

confidence: 89%

Rockfall-induced impact force causing a debris flow on a volcanoclastic soil slope: a case study in southern Italy

Budetta

2010

Nat. Hazards Earth Syst. Sci.

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“…Ainda dentro do laboratório, Dias e Barroso (2006) determinaram o ε normal de um gnaisse por intermédio do registro sonoro de sucessivos impactos de uma esfera rochosa em uma superfície horizontal, de acordo com método acústico proposto por Bernstein (1977). Testes in situ foram executados por Giani et al (2004), em que blocos de rocha foram lançados do topo da encosta no Apeninos (Itália) e câmeras posicionadas ao longo do percurso gravaram a trajetória do bloco. A partir da análise das imagens, parâmetros como velocidade, ângulo de rotação dos blocos e os coeficientes de restituição foram definidos.…”

Section: Conhecimento Do Problemaunclassified

Influência do grau de saturação no módulo de elasticidade dos solos: aplicação à previsão do alcance em quedas de blocos de rochas

Castro

Ribeiro

Barroso

et al. 2018

Geol. USP. Sér. cient.

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Disponível on-line no endereço www.igc.usp.br/geologiausp -139 -Resumo O processo de queda de blocos rochosos é um dos mais destrutivos movimentos de massa em encostas. Considerando a baixa previsibilidade da sua deflagração, tem sido dada atenção à determinação das trajetórias dos blocos como método para redução de riscos. O coeficiente de restituição (ε) é o principal parâmetro físico envolvido na análise do alcance dos blocos, pois representa as perdas de energia após os choques do bloco de rocha com diferentes materiais geológicos em sua trajetória. Trata-se de um parâmetro ainda pouco conhecido na literatura geológica e geotécnica, sobretudo quando se considera a interação dos blocos de rocha com solos em diferentes umidades. Este artigo teve a finalidade de avaliar o efeito da umidade do solo sobre o módulo de elasticidade (E), parâmetro elástico que afeta a rigidez no contato entre rocha e solo no momento do choque e, por conseguinte, o próprio ε. Para fins de comparação, um solo derivado de rocha ácida e outro de rocha básica foram coletados na região serrana do Estado do Rio de Janeiro. Procedeu-se à caracterização da mineralogia das rochas de origem e dos solos derivados, bem como dos índices físicos dos solos. Após a determinação da curva característica, os solos foram moldados em diferentes teores de umidade e submetidos a ensaios de compressão triaxial do tipo não adensado e não drenado. Os resultados mostraram variação de mais de uma ordem de grandeza do (E) em função da umidade do solo, indicando que esta tem considerável influência na rigidez do contato entre o solo e a rocha, tornando os alcances dependentes da variação sazonal de umidade nas encostas.Palavras-chave: Módulo de Elasticidade; Umidade do Solo; Rigidez nos Contatos. AbstractRock falls are one of the most destructive mass movements in hillslopes. Considering the low predictability of its triggering, attention has been paid in determining the paths of the blocks as a method to reduce risks. The coefficient of restitution (ε) is the primary physical parameter involved in the analysis of the reach of the blocks. It represents the loss of energy after each shock of a rock block with different geological materials in its trajectory and it is still little known in geological and geotechnical literature, especially when considering the interaction of rock blocks with soil at different humidities. This article aimed to evaluate the effect of soil moisture on the elasticity modulus, an elastic parameter that affects the stiffness at the contact between rock and soil at the time of shock and, therefore, the actual coefficient of restitution. For comparison purposes, soils derived from acid rock and from basic rocks were sampled in the mountainous region of the State state of Rio de Janeiro. The procedure was to characterize the mineralogy of source rocks and its derived soils, as well as the physical indices of the soils. After determining the characteristic curve, the soils were molded at different moisture contents and subjected to unconsoli...

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“…Protective flexible wire net and embankment are typical in such design (Giani et al, 2004;Labiouse, 1996;Peila et al, 1998). There is normally a strong collision behaviour when the rockfall impacts the protection measures.…”

Section: Introductionmentioning

confidence: 99%

Impact of rockfalls on protection measures: an experimental approach

Yuan

Huang

et al. 2015

Nat. Hazards Earth Syst. Sci.

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Abstract. The determination of rockfall impact force is crucial in designing protection measures. In the present study, laboratory tests are carried out by testing the weight and shape of the falling rock fragments, drop height, incident angle, platform on the slideway, and cushion layer on the protection measures to investigate their influences on the impact force. The test results indicate that the impact force is positively exponential to the weight of rockfall and the instantaneous impact velocity of the rockfall approaching the protection measures. The impact velocity is found to be dominated not only by the drop height but also by the shape of rockfall and the length of the platform on the slideway. A great drop height and/or a short platform produces a fast impact velocity. Spherical rockfalls experience a greater impact velocity than cubes and elongated cuboids. A layer of cushion on the protection measures may reduce the impact force to a greater extent. The reduction effects are dominated by the cushion material and the thickness of the cushion layer. The thicker the cushion layer, the greater the reduction effect and the less the impact force. The stiffer the buffer material, the lower the buffering effect and the greater the impact force. The present study indicates that the current standard in China for designing protection measures may overestimate the impact force by not taking into consideration the rockfall shape, platform, and cushion layer.

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Experimental and Theoretical Studies to Improve Rock Fall Analysis and Protection Work Design

Cited by 134 publications

References 5 publications

Rockfall-induced impact force causing a debris flow on a volcanoclastic soil slope: a case study in southern Italy

Rockfall-induced impact force causing a debris flow on a volcanoclastic soil slope: a case study in southern Italy

Influência do grau de saturação no módulo de elasticidade dos solos: aplicação à previsão do alcance em quedas de blocos de rochas

Impact of rockfalls on protection measures: an experimental approach

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