Hench Wang, Peter Hill, Sam Banzi, Muhammad Hameed
Dam owners can often struggle to demonstrate the dam safety risk benefits that can be achieved through non-structural risk reduction measures, such as adoption of smart technological solutions that improve the timeliness and quality of decision making. WaterNSW collaborated with HARC to develop a novel way of demonstrating benefits from improved data management. This paper discusses the use of HEC-LifeSim to demonstrate the reduction in life safety risk from improved monitoring through DamGuard for a case study dam in Sydney. DamGuard is a real-time dam safety monitoring system implemented by WaterNSW. This case study was the first time in Australia where a simulation model such as HEC-LifeSim was applied to quantify the life safety risk benefits pre and post the implementation of DamGuard. The implementation of DamGuard to the sample dam was estimated to reduce the life safety risk by 15%.
The confluence of several technological innovations including drones, photogrammetry, and thermal imaging has enabled the development of a novel approach to defect mapping and monitoring for large dams. A pilot project trialling the methodology was completed at a rockfill embankment dam with a concrete spillway and is presented as a potential means of improving the accuracy and reliability of condition monitoring. The pilot project included two main objectives: digital inspection and mapping of defects within the concrete spillway; and drone-based photogrammetric survey of the rockfill embankment. Defect mapping of the concrete spillway utilised drone-based photography and Structure from Motion (SfM) photogrammetry to develop a high-fidelity 3D model, from which visual defects could be identified and mapped in a virtual environment. Thermal infrared (IR) imagery of the structure provided an indication of potential shallow subsurface defects in the concrete. Photogrammetric survey of the embankment structure utilised drone-based photography, SfM photogrammetry and a network of precisely surveyed ground control and verification points to develop a georeferenced point cloud, digital elevation model and elevation contours. The results of the project were delivered via a web-based digital twin which included georeferenced results from defect mapping, aerial survey and tools for visualisation, measurement, and reporting.
Michael Ashley, John Phillips
New guidance and publications relating to tailings dams have been released recently by many jurisdictions across the world as an initial response to recent, well-documented, catastrophic tailings dam failures. The application of new guidelines retrospectively to existing tailings projects can introduce complex challenges, especially for sites with a long and often not well documented history. Challenges can be difficult to overcome while balancing time, cost and risk objectives.
This paper explores the impacts of changes between the 2012 and 2019 revisions of the ANCOLD Guidelines on Tailings Dams and potential implications for existing facilities.
The most significant update between the 2012 and 2019 revisions of the guidelines relating to design practices is the additional detail and guidance on seismic stability analyses and static liquefaction. Guidance on the application of new guidelines for tailings dam designers, owners and regulators is required to provide a consistent approach to manage the risk.
Richard M Robinson, Siraj Perera, Gaye Francis
Due diligence has become endemic in Australian legislation and in case law, to the point that it has become, in the philosopher Immanuel Kant’s terms, a categorical imperative. That is, our lawmakers seem to have decided that due diligence is universal in its application and creates a moral justification for action. This also means the converse, that failure to act demands sanction against the failed decision maker.
This applies to dam safety management which represents the archetypical high consequence – low likelihood event. It is now essential to have positively demonstrated safety due diligence in a way that can withstand post-event judicial scrutiny. Presently the only way this can be done is by using the notion of criticality and precaution, not hazard and risk. The test is not that of risk acceptability (as low as reasonably practicable or ALARP), rather it is that no further reasonably practicable precautions (so far as is reasonably practicable or SFAIRP) are available, and that what results is not prohibitively dangerous.
This paper will document the difference between the two approaches and how to positively demonstrate safety due diligence. It also discusses the definition of ALARP as stated in ANCOLD’s Guidelines on Risk Assessment 2003 and the relevance of the safety case principle for dam safety management.
Matthias WILD, James STEWART, Chris IRVIN, Sander Van Ameijde
The awareness of safe and sustainable utilisation of all forms of construction such as bridges, tunnels, dams or industrial buildings during its whole lifetime is increasing more and more. The safe operation of our dams is of critical importance to society. As our assets age, the focus on monitoring, control systems and lifespan management is of increasing importance. Communities need to have peace of mind these assets are not going to fail. To prevent failures of structures, a common method is for periodical or situational site visits to check the crucial points of construction. Site visits are cost intensive, subjective and non-continuous. This results in a global research focus on measurement devices and evaluation systems to generate a full structural health monitoring system which guarantees measurement and data evaluation adapted for the specific application over the full lifespan.
For important structures like the Hinkley Point nuclear power plant or Australian Dam structures it’s not just the inspection costs and a sustainably utilisation during service life that are important. The safety during operation of the nuclear power plant is also critical to its operation. To monitor the deep excavation at the power plant DYWIDAG provided geotechnical systems combined with measurement sensors and a monitoring concept for the lifespan of the structure. About 14,000 soil nails and bar anchors are stabilising the excavation. Movements of the retaining wall will lead to a change of stress in the geotechnical tension members. This change is monitored by DYNA-Force Sensors, which are used for load monitoring. This monitoring system has been used successfully in a range of critical structures like stadium roof-beams, staycables, dam-anchors with strands or bars.
A simple installation and read out of sensors is not a major facilitation compared to site visits. The implementation of sensors in a sophisticated monitoring system is the big advantage of structural health monitoring which guarantees a safe and sustainable utilisation of the construction. DYWIDAG is making infrastructure lifespan management smarter and offers a cloud-based online sensor management system (Platform Interactive) which enables processing of large volumes of sensor data and performing complex calculations. It provides real-time alerting, presenting the information in an innovative and interactive way, removing subjective interpretation and providing numerical data online in real time. Platform Interactive with plug and play pre-configured sensors, may also be adapted and applied for a range of SHM projects. It provides continuous reporting and the reassurance structures are performing as they should without the possibility of failure. At DYWIDAG we are making infrastructure lifespan management smarter, safer, stronger
Ryan Singh, Jiri Herza, James Thorp
Recent and continual failures of tailings storage facilities (TSFs), often resulting in catastrophic consequences, has led to calls for action from the industry, stakeholders and the public at large. Several standards and guidelines are being prepared at the time of writing, most notably a Global Industry Standard on Tailings Management (GISTM), with the overall objective to reduce the rate of TSF failures globally. While better guidelines are certainly necessary, there are requirements that must be carefully followed in developing a document that has the ambition to become a standard. If such requirements are not fulfilled, the document can become ineffective or potentially have the opposite result to that which was intended. This paper discusses whether or not the GISTM meets the requirements of the standards and analyses the potentially negative impacts of its implementation on the industry and wider society. Based on this analysis, this paper provides several recommendations for improvements that should be considered by the GISTM panel and other working groups preparing standards and guidelines.