Proposed rockfall rating system based on system safety

• Main Author: Lee, Hui Jie.
• Other Authors: School of Civil and Environmental Engineering
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Civil engineering
• Online Access: http://hdl.handle.net/10356/53837
• Institution: Nanyang Technological University

Rockfall is a natural hazard which may result in various detrimental effects such as economic loss and human casualties. In the light of the negative impacts of rockfall events, some organizations have devised Rockfall Hazard Rating System (RHRS). Rockfall rating is a risk assessment tool that provides insights to decision makers so that informed decision can be made to adopt other possible control and mitigation measures. There are numerous rockfall rating systems currently adopted in different parts of the world, each rating system varying slightly from one another. However, for most rating systems, little information is given as to what to do with the rating scores. The inadequate approach to fully make use of rating scores to assess risk is a major motivation for this research. This paper reports on the authors’ efforts in improving the existing rockfall rating system in which the relative importance of rockfall parameters and system safety would be taken into account. The validations of rockfall parameters are examined and industry survey was conducted to find out the relative importance of rockfall parameters. The proposed rockfall rating table consists of two parts, namely the probability of rockfall and the consequences of a rockfall event. A risk matrix with guided rating scores is also presented to show the relationship between rating scores and the four risk classes which are High, Serious, Medium and Low. Furthermore, about 20 case studies were used to validate the proposed rating system and making comparison to the existing Oregon RHRS. The author hopes that the proposed rockfall rating system and other relevant findings would be useful for assessing rock slopes in Singapore and further studies relating to rockfall rating system and rockfall risk assessment. Keywords: Rockfall rating system, rockfall hazard system, risk assessment, system safety