An Uncoupled Approach for the Design of Rockfall Protection Tunnels

Calvetti, Francesco; Prisco, Claudio di

doi:10.2749/101686609788957892

Cited by 7 publications

(2 citation statements)

References 4 publications

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“…Among them, in the case of RC/PC rock shed (Figure 1), a soil material (sand, locally generated soil, etc.) is installed as a cushioning material on the top slab to reduce the impact force caused by falling rocks [5][6][7][8][9]. When it is necessary to improve the impact resistance of the rock shed, a method has been applied in which the cushioning material on the top plate is replaced with a material having a high cushioning performance such as a foam material from a soil material [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Impact Absorption Capacity of Various Expanded Materials for Rock Shed

Kurihashi

Kogure²,

Nitta³

et al. 2020

Shock and Vibration

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In recent years, there has been a continuous increase in the intensity of natural disasters. Slope disasters such as rock falls occur along coastlines and in mountainous regions. Rock shed structures are implemented as measures to prevent rock fall damage; however, these structures deteriorate over time, and their impact resistance also decreases. As a supplementary measure, a method employing foam material as a cushioning material has been used in practical applications. However, the effect of the compressive strength characteristics on the cushioning performance of foamed materials has not been studied thus far. Therefore, in this study, falling-weight impact-loading tests involving various fall heights were performed to examine the absorption performance of various expanded materials. Moreover, we examined the case where core slabs were layered to effectively exploit the absorption performance of the expanded materials. The results of this study are summarized as follows: (1) the transmitted impact penetration stress-strain curves right under the loading points of various expanded materials exhibit properties similar to those obtained from the results of material testing. However, in the case of expanded materials with high compressive strengths, the compressive stress from the results of material testing tends to be lower. (2) In the case of expanded materials with high compressive strengths, with and without core slabs, the distribution of the transmitted impact stress is large, and the energy absorption capacity is high. (3) In this experiment, the energy absorption capacity was found to double when core slabs are layered, regardless of the type of expanded material used. This suggests that expanded materials with high compressive strengths may contribute towards a higher improvement in energy absorption capacities, by using layered core slabs.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on Impact Absorption Capacity of Various Expanded Materials for Rock Shed

Kurihashi

Kogure²,

Nitta³

et al. 2020

Shock and Vibration

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“…e Japanese Road Association developed a semiempirical and semitheoretical calculation method for rockfall impact force using model experiments (hereinafter referred to as the Japanese method) [16]. Calvetti and Prisco analyzed the design method for shed tunnel structures based on the uncoupled calculation method [17]. Ye and Chen performed a comparative study on rockfall impact force values by employing the Japanese, Swiss, and Hertz methods in conjunction with an engineering model [18].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Analysis of Rockfall Impacts on the Soil Cushion Layer of Protective Structures

Wang

Xia

Zhou

2018

Advances in Civil Engineering

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During the Wenchuan Earthquake, with a magnitude of 5.12, collapses and rockfall hazards persisted for a long time after the initial investigations carried out by research fellow S. M. He and his team at the scene of the disaster in October 2008. It is possible that additional incidents of rockfalls in large quantities may continue in the same areas over the next ten to fifteen years. Furthermore, in the vast mountainous region of western China, the topographic relief is evident, and earthquakes occur frequently. Therefore, it is difficult to effectively defend against rockfall hazards. When designing protective structures, the key issue is the analysis of the mechanical response mechanism of the soil cushion layer of the upper cushion when subjected to the impact of rockfall. As such, a theoretical method was used to perform such an analysis. The cavity expansion and energy conservation model were adopted. Analytical solutions for the impact force and penetration depth were then derived. Furthermore, the impact force and penetration depth of rockfall were studied with the LS-DYNA software to obtain values for the impact forces and the penetration depth. Finally, the reliability of the theoretical method was evaluated using the cavity expansion, energy conservation, numerical simulation, Hertz, Japanese, Swiss, Australian, B. S. Guan, tunnel manual, and subgrade methods based on an engineering model. The results show that the cavity expansion and the energy conservation methods yielded consistent results. Meanwhile, the cavity expansion and the energy conservation methods also yielded consistent results with the numerical simulation, Japanese (obtained by laboratory experiment), Swiss (obtained by laboratory experiment), and Australian (obtained by field experiment) methods. The relevant methods and conclusions shall therefore be applied to the design of rockfall protection structure in future investigations.

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