Rockfall is an extremely rapid process involving long travel distances. Due to these features, when an event occurs, the ability to take evasive action is practically zero and, thus, the risk of injury or loss of life is high. Damage to buildings and infrastructure is quite likely. In many cases, therefore, suitable protection measures are necessary. This contribution provides an overview of previous and current research on the main topics related to rockfall. It covers the onset of rockfall and runout modelling approaches, as well as hazard zoning and protection measures. It is the aim of this article to provide an in-depth knowledge base for researchers and practitioners involved in projects dealing with the rockfall protection of infrastructures, who may work in the fields of civil or environmental engineering, risk and safety, the earth and natural sciences.

In 2009, the European Guideline for Flexible Rockfall Protection Kits European Technical Approval Guideline 027 (ETAG 027) became valid. The aim of the guideline was to approve and certify steel barriers available on the market according to a common standard. In 2018, ETAG 027 was replaced by a so-called European Assessment Document (EAD). This contribution summarizes results and experiences that were obtained through the type testing, approval and assessment procedures of 66 protection systems evaluated between 2009 and 2018. Apart from the common main task of the barriers to stop falling blocks successfully, the different test conditions and constructions of barriers result in different performance characteristics. Some of these characteristics follow certain trends, whereas others show a wide range without any trend. In such a case, this contribution helps to classify a single system compared to the others.

Numerical simulations of rockfall trajectories are a standard procedure for evaluating rockfall hazards. For these simulations, corresponding software codes must be calibrated and evaluated based on field data. This study addresses methods of repeatable rockfall tests, and investigates whether it is possible to produce traceable and statistically analysable data. A testing series is described extensively covering how to conduct rockfall experiments and how certain elements of rockfall trajectories can be measured. The tests use acceleration and rotation sensors inside test blocks, a system to determine block positions over time, surveying measurements, and video recordings. All systems are evaluated regarding their usability in the field and for analyses. The highly detailed description of testing methods is the basis for sound understanding and reproducibility of the tests. This article serves as a reference for future publications and other rockfall field tests, both as a guide and as a basis for comparisons. First analyses deliver information on runout with a shadow angle ranging between 21 and 45 degrees for a slope consisting of homogeneous soft soil. A digital elevation model of the test site as well as point clouds of the used test blocks are part of this publication.

In determining rockfall trajectories in the field, it is essential to calibrate and validate rockfall simulation software. This contribution presents an in situ device and a complementary Local Positioning System (LPS) that allow the determination of parts of the trajectory. An assembly of sensors (herein called rockfall sensor) is installed in the falling block recording the 3D accelerations and rotational velocities. The LPS automatically calculates the position of the block along the slope over time based on Wi-Fi signals emitted from the rockfall sensor. The velocity of the block over time is determined through post-processing. The setup of the rockfall sensor is presented followed by proposed calibration and validation procedures. The performance of the LPS is evaluated by means of different experiments. The results allow for a quality analysis of both the obtained field data and the usability of the rockfall sensor for future/further applications in the field.

Flexible debris flow protection barriers consist of a combination of steel ropes and high tensile steel wire nets following certain design criteria to provide a reliable protection against the sudden impact of a debris flow with flow heights of up to 2 m and middle front velocities of around 10 m/s in channelized river beds with widths and heights up to 30 m and 6 m. However, to go beyond the above described typical application range special design is required. In the actual case a debris retention basin with a height of 14 m and a width of 40 m was created. The contribution shows the precedent research on flexible debris flow barriers consisting of field tests and laboratory experiments, leading to the validated numerical simulations. Main focus then is the design process of the special purpose barrier, its construction together with the experiences gathered within the project leading to a not only remarkable but also elegant way to protection from impressive debris hazards.