The conventional design approach of any type of passive protection work aiming at reducing the risk associated with rockfall is energy-based: the total kinetic energy of the falling block in a given position of its trajectory (action, in Limit State Design (LSD) terminology) must be compared to the maximum energy absorption capacity of the protection work (resistance, in LSD terminology). The LSD approach, implemented in Eurocode 7 (EC7), shows some limitations in the case of unconventional geotechnical problems such as rockfall phenomena, since the main parameters of these systems are not considered. To overcome these limitations, one proposed solution is the application of Reliability Based Design (RBD) approaches through the definition of a reliability index, a useful and complementary tool to provide geotechnical structures with a uniform probability of failure. The RBD approach deals with the relationship between the loads that a system must support and the system's ability to support those loads. The RBD therefore shifts the analysis towards a fully probabilistic one, in which each parameter is considered a variable expressed by a known Probability Density Function (PDF). In this work, attention has been given to innovative rockfall protection structures such as hybrid barriers and/or attenuators: they do not stop the block by capturing and retaining it in a deformable net, but by dissipating its kinetic energy (up to 0 for hybrid barrier) and forcing it along a trajectory close to the ground or guiding it towards a collecting area. Therefore, in ideal conditions, the block does not stop within the net itself. Considering the applicability of a RDB approach, the paper will focus on the description of the rockfall phenomenon, namely the action on the hybrid barrier/attenuator. To describe the process of a moving block impacting it, two main parameters are identified: the Total Kinetic Energy (E_k) and the position of the impact location with regard to the structure. Assuming a 2D simplification of the problem, the second parameter corresponds to the height of bounces (H) in a given position along a slope. This works shows how, by employing a robust statistical approach and a suitably large set of numerical simulations, it is possible to define the Cumulative Distribution Functions (CDFs) of these parameters. From these two curves, it is possible to identify, through the use of proper statistical tests, the best-fitting PDFs and, therefore, use them as input for a probabilistic design approach such as RBD.

El Caminito del Rey, a renowned hiking trail located in the province of Malaga, Spain, is not only celebrated for its breathtaking beauty, but also for its notable susceptibility to rockfalls. The trail traverses a rugged terrain characterized by towering cliffs comprised of various rock formations, including limestone and conglomerate. The structural integrity of these rocks is gradually compromised over time due to weathering processes such as freeze-thaw cycles and erosion. When coupled with the influences of gravity, vibrations arising from human and wildlife activity, as well as natural seismic events, the stability of the cliffs becomes compromised, resulting in frequent occurrences of rockfalls along the trail. Despite persistent efforts to mitigate these risks, such as regular inspections and the installation of protective barriers, the inherent geological nature of the gorge renders the complete prevention of rockfalls an intricate challenge. In light of these circumstances, this study aims to take the initial steps towards implementing an advanced safety system on El Caminito del Rey with regards to rockfall hazards. The primary component of this undertaking involves the development of a susceptibility model based on rockfall simulations. The process unfolds in three key stages. Firstly, a comprehensive virtual 3D model of El Caminito is generated. Secondly, ancillary data and meticulous characteristics of the rocks constituting the gorges are compiled and incorporated. Lastly, utilizing the aforementioned information, rockfall events are simulated. This abstract will expound upon the challenges surmounted during the course of the project, as well as provide an overview of the principal findings. Furthermore, the forthcoming research agenda for the area will be outlined, seeking invaluable feedback from the interested audience. This feedback will play a crucial role in guiding future research efforts in El Caminito, with the ultimate objective of enhancing the safety of the trail. While the allure of El Caminito del Rey's awe-inspiring scenery remains undeniable, the trail managers are diligently prioritizing visitor safety by proactively preparing for potential rockfall hazards. Through the implementation of an advanced safety system informed by the findings of this study, the aim is to strike a balance between preserving the enchanting experience offered by El Caminito and ensuring the well-being of its visitors.

The Aurunci and Riviera di Ulisse Regional Parks are known for their cultural landscape and related trails that, every year, are hiked by thousands of visitors. The “San Michele Arcangelo” historic trail is the most important trail of the Aurunci Regional Park (central Italy) and forms the cultural asset of the park. The trail is located along the southern slope of Mt. Altino, prone to rockfalls, and is hiked every year by thousands of faithfuls on pilgrimage who are exposed to such kind of instabilities. The trail of Punta Cetarola in the Riviera di Ulisse Regional Park is a significant example of coastal trail, corresponding to a segment of the ancient “Flacca” road and, similar to the “San Michele Arcangelo” historic trail, is developed along a slope prone to rockfalls. To contribute to a better understanding of the condition of development and evolution of rockfalls in these two areas, providing a susceptibility scenario able to support the adoption of mitigation measures, a specific analysis was completed on the basis of field and literature data. Photogrammetric reconstruction of accessible slope sectors and scan-line-based field outcropping analyses were completed to derive geomechanical features of rocks and estimate potential detaching block volume. Possible mechanisms of detachment were analyzed using the reduced complexity Markland test method. Susceptibility to rock block detachment, rockfall propagation and block deposition was analyzed using GIS processing and deterministic/probabilistic propagation analyses. In particular, adopting the Rockyfor3D software, results of slope analyses and simulations indicated: i) the potential for rock blocks detachment by wedge and planar sliding or toppling, ii) the localization at higher elevations over the whole study area of slope sectors susceptible to block detachment, iii) the moderate susceptibility to both propagation and deposition of rock blocks along the trail, iv) the control exerted by the hydrographic network on rockfall propagation, v) the control exerted by screes and slope angle on rockfall deposition.

Coastal communities face recurring erosion problems and flooding. It is complex to carry out a technical-economic balance, which allows for finding an effective solution. With increasing risks and associated management costs a congruent solution designed, which consists of the conformation of modules, composed of an exoskeleton of rhomboidal meshes of high yield strength (>1650MPa) stainless steel duplex, rock block fill, which can be executed in place or precast. This solution designed by gravity, in which the structure's weight plays an essential role, is efficient when faced with certain significant wave height and slope inclination conditions. For its design, in addition to the demands in energy and uplift terms, the abrasion generated in the components, the sediment dragging process that causes both the entry and exit of the water from its bracing, only the use of stainless steel as the only material, guarantees the effectiveness.

Coal Pillars are important structural elements in underground mining. Unstable pillars can result in collapse of roof and walls and even coal burst; hence its reliability analysis is of great importance. This paper presents a novel probabilistic framework to assess system reliability of section pillar. The variation of coal mass parameters, such as UCS, friction angle, cohesion and Young’s modulus, are considered. Two different failure modes, with respect to pillar stress and strain, are investigated to obtain reliability indices using FLAC3D, Stochastic response surface (SRSM) and First-order reliability method (FORM), then Bimodal bound and Linearization methods are adopted to compute system failure probability. Finally, coal mass parameters from a typical coal mine are employed and results suggest that both stress and strain limit states could have significant influence on the system reliability. The approach proposed in this paper could be a useful tool on the risk management of underground pillar.

Secured drapery systems with meshes have been used for years to stabilize the surface material in slopes and ensure the safety in different infrastructures. Historically, one of the first materials used as a mesh was double-twisted mesh. Over time, the need for materials with higher performanc-es arose, leading to the installation of steel cables or rope panels over the mesh, which was a slow and labor-intensive process. Furthermore, it is necessary to verify the use of meshes in the design, as geomechanical models are often complex and unrealistic. Key mechanical characteristics for de-sign are the tensile strength, punch resistance, and punch deformation. However, the transverse ten-sile strength is often overlooked, despite evidence showing its relevance. This article presents a re-liable numerical model calibrated using laboratory tests. It demonstrates the influence of transverse tensile strength on deformation and punch resistance, enabling the optimization of bolt design with-in secured drapery systems.