Canada’s railway system is an integral component of our economy, transporting people and goods safely and efficiently across the country, to and from global markets. Maintaining a safe and efficient transportation network is a top priority for Canada’s railway industry and Transport Canada. A key factor in railway safety is managing the risk from ground hazards.
Phase 2 Research Objectives
1. Perform scientific research and investigations to better understand the mechanisms that cause various ground hazards, develop guidelines to manage the risks, and develop and identify tools and technologies to mitigate the hazards.
2. Produce a manual for railway geotechnical engineers and consultants to identify the ground hazard, its causes and risks, along with recommended risk management and mitigation tools, technologies, and strategies.
Ground Hazard Risk Identification and Analysis
In order to properly assess and reduce the risks posed by ground hazards, the railways must be able to track the hazard and the associated risk. This can only be accomplished if the ground hazards are classified and described using a consistent technical process. The purpose of this work is to establish Ground Hazard Terminology and Scenarios for documenting and reporting ground hazards and ground hazard events. The results to date have been a detailed classification system for all railway related ground hazards base on mechanism and triggers. Ongoing work includes the development of an industry standard for ground hazard reporting and documentation.
Ground Hazard Event Triggers
In order to properly assess and reduce the risks posed by ground hazards, the railways must also understand the conditions which trigger ground hazard events. Ground hazards can be triggered precipitation, seismic events, freeze-thaw cycles, river scour and erosion, rapid snowmelt, and dynamic loading conditions as trainloads increase. To date, an evaluation of the environmental factors which influence risk has been conducted, drawing correlations between meteorological and ground hazard events from 122 years of records.
Technology for the Monitoring & Evaluation of Ground Hazards
The purpose of this project is to evaluate new and emerging technologies for the monitoring of ground hazards, such as large slopes and rock faces, which may pose threats to the railway. Several technologies are currently being evaluated, including:
• Static laser scanning (LiDAR) for the analysis of rock faces and rock slopes to assess stability and associated risk. This includes the development of progressive scans to measure movement and changes in surfaces due to rockfalls.
• Terrestrial base InSAR (satellite radar interferometry) for the stability of large rock slopes and cuts along railway corridors. This technology can measure millimeter movements from distances of over a kilometer.
• A comparison of several rockslide monitoring technologies at a large-scale instrumentation installation where the CN line crosses the large active Gascons rockslide on the Gaspé Peninsula.
• Ground Penetrating Radar (GPR) to evaluate soft soil foundations to determine mechanisms resulting in track alignment degradation.
The current method for monitoring rockfall events is with a trip wire system. While this system is reliable in detecting rockfalls, it is prone to false alarms and requires time to reset once triggered, during which trains must run at very low speeds. The purpose of this work is to develop a seismic rock fall detector that can replace existing trip-wire detectors (or rock slide fences) to decrease the time required to reset systems and return to normal train speeds and line capacity. The system is currently being tested for reliability and ability to differentiate quantity and proximity of fallen rocks to rails. The result of this work will improve train reliability, safety, and on-time performance.
Heavy Axle Loading over Soft Subgrades
Both CN and CP railways are experiencing continuing problems with large stretches of embankments built over peat. These problems range from excessive settlements requiring increased amounts of maintenance to sudden failures of these embankments.
The purpose of this work is to study the impact of heavy axle loading on aging track infrastructure and the soft peat foundations under these structures. Several sites have been investigated and extensively instrumented. This instrumentation has included the development of new Micro Electro Mechanical Systems (MEMS) base technology to measure cyclic displacement of soil with depth during the passage of trains.
Risk Mapping of Sensitive Clays
A large portion of the railway lines in Eastern Canada are built over thick deposits of soft sensitive clays and are vulnerable to sudden landslides. The purpose of this work is to use new understanding of sensitive landslides and new mapping and monitoring technology to pinpoint areas of concern along tracks in relation to sensitive clays. The results of this work to date have included comprehensive maps and guidelines to help prevent activation of disastrous slides. The goal is to provide operators with developed maps and guidelines to reduce hazard levels which can be also used to protect other types of transportation corridors (pipelines, roads, etc).
Fouling of ballast (the layer of crushed rock or gravel upon which railway track is laid) is a process by which ballast is filled with fine-grained material. The result of this is a reduction in the ability to drain and a reduction of shear strength. The purpose of this work is to develop a field sampling methodology and analysis of the mechanism and source for fouling. In addition to sampling, the future goals of the project are to: evaluate the use of Ground Penetrating Radar (GPR) for determining the degree of ballast fouling on sites; evaluate the effectiveness undercutting as a ballast remediation technique; and evaluate the effectiveness of mitigation techniques such as drainage and reinforcement on fouling mechanisms.