Aug 27, 2020
Geohazards are areas of danger created by unstable geology. Some geohazards form naturally over thousands of years, however, some are created by construction or excavation work—where failures can happen within minutes, potentially destroying property and threatening life. Geohazards are typically dormant until they are triggered by a geologic event. Where population density is high, or where valuable transportation infrastructure is located, that event can be catastrophic. Monitoring ground deformation is a proactive way to mitigate the risks associated with these disasters.
A landslide is a common geohazard caused by slope failure that triggers soil, sediment, rock and debris to move down a slope. Landslides can threaten infrastructure and public safety. According to the Government of Canada, Slope failures in Canada create $200 to $400 million in direct and indirect costs annually.
Where unstable slopes exist next to important infrastructure like roads, railways, and pipelines, geotechnical sensors that collect data can reduce the risk posed by geohazards.
Measurand designs and manufactures ShapeArray, an innovative and patented geotechnical deformation monitoring instrument. ShapeArray is an inclinometer-style instrument made of rigid stainless-steel segments and flexible joints. Within each rigid segment is a micromachined electromechanical systems (MEMS) accelerometer and temperature sensor that measures tilt and inclination to detect changes in shape. ShapeArray is the only geotechnical instrument with a patented cyclical installation method that makes using the ShapeArray easy. Simply insert ShapeArray directly off the reel into nearly any diameter casing without requiring grout or field-based calibration. With its narrow bend radius and diameter, ShapeArray can be installed where other inclinometers cannot, making it extremely versatile.
In general, a ShapeArray can be installed in three orientation to measure different type of movements:
Data collection can be automated to provide engineers and key stakeholders with the real-time information they need to make better decisions based on observable measurement.
Measurand’s ShapeArray can measure the movement of structures like tunnels, retaining walls, dams, and buildings in real-time, which is ideal for transportation infrastructure monitoring:
In 2008, the ShapeArray detected deeper than expected subsurface movements along a stretch of highway in Minnesota. Data was automatically collected for remote analysis and traffic was diverted to another route. Ten days later, a large progressive landslide dropped a 150 m section of the roadway down three metres—an event that could have resulted in catastrophic failure.
The ShapeArray has proven its worth in rail applications, monitoring precise ground movements (lateral deformation) during tunnel boring machine (TBM) excavations for two multi-billion dollar rail projects in California and Edmonton.
Overseas, ShapeArray supported two large British rail infrastructure projects: the Crossrail and the Northern Line Extension. Monitoring settlement and tunnel convergence, ShapeArray reduced onsite risk, creating a safer work environment during the construction of retaining structures, by reducing the need for technicians to access the sites to collect data.
Called Britain’s biggest environmental project and the largest infrastructure decision since World War Two, the ambitious HS2 high-speed rail network is designed to be a sustainable and ecologically important transportation infrastructure project.
To hit carbon emission net-zero by 2050, the HS2 invested heavily in the ecological landscape along the tracks: woodlands, wildlife bridges and underpasses, and planting over 7 million trees. The train will travel at speeds of 400 kph emitting 8 g of carbon every kilometre, making it 17 times more efficient than air travel, seven times more efficient than road travel, and twice as efficient as the current overburdened rail system (HS2 media).
On the human side, the HS2 will cut travel time by almost half from London to Birmingham, improve bottlenecks on existing lines, reduce commuter delays, and improve the rush hour experience.
The design phase of the HS2 spanned a decade, detailing the environmental and technological innovations required to preserve the natural environment and protect passenger safety. Government approval came in February 2020, after extensive public and private consultation.
In April, the Department for Transport told the four Main Works Civils Contractors (MWCCs) to proceed. Phase One will link London to Birmingham between 2020 and 2031. Phase Two extends the track to Leeds with a projected end date of 2040. The approval has been met with some criticism:
“HS2 Ltd has been widely criticised for not factoring-in enough risk and uncertainty into its calculations…One of the big unknowns, which was underestimated on the first phase, was ‘ground conditions.’”
“HS2: Six reasons why the rail route is so expensive”—(BBC)
Transportation infrastructure of this magnitude, winding across and under a crowded landscape with miles of underground tunnels, requires real-time monitoring to protect assets, environmental benchmarks, onsite contractors, and the dense population surrounding the project.
During site preparation, risk reduction should be a priority—one that the ShapeArray is well-positioned to handle with state-of-the-art sensors and real-time responsiveness. Manual monitoring using visual onsite observations could be cost-prohibitive and time-intensive.
ShapeArray would be an indispensable instrument as HS2 stakeholders launch one of the most environmentally-focused infrastructure projects in the world.
Measurand is a trusted geotechnical instrumentation company that provides fast, simple, and precise monitoring of geohazards. ShapeArray delivers real-time data collection for transportation infrastructure projects where mitigating risk and increasing safety is a priority.
To learn more about ShapeArray, contact Measurand today.