We measure subsidence for underground transportation network expansion including tunneling for the metro, highway, and railway lines.
Transportation tunnels are usually built close to the surface and near populated areas leading to a risk of tunneling induced subsidence that can cause structural damage on the surface and claims for damage compensation. Furthermore, tunneling can modify hydrologic conditions around the excavation area.
Assessment of the influence of tunneling on the above ground structures has therefore become a crucial issue to predict deformation and avoid or mitigate potential damage.
The advantage of InSAR technology is that we measure subsidence over large areas at affordable costs, guaranteeing that the reference point is located beyond the subsidence bowl. With piezometric data, we analyze correlations between subsidence and piezometric data to predict subsidence that occurs as a consequence of planned water pumping activities.
Ground subsidence is one of the key factors damaging transport facilities such as railway, highway and subway networks. Subsidence along transportation networks impairs the sustainability and stability, thus resulting in a great risk for traffic safety.
Subsidence on transportation networks can be caused by excessive groundwater exploitation (especially in areas with increasing industrial production), by heavy loads from vehicles, by unstable ground (soft soil, loose rock, clay, etc.) or by unstable surroundings (e.g. landslides in mountainous areas). Global subsidence analysis with radar satellites combined with in situ data enables transportation companies to identify vulnerable areas and assign different levels of risk to each part of the tracks. This allows for optimal allocation of maintenance budget and guarantees the best traffic safety at a minimum cost.
Bridges and overpasses represent one of the most vulnerable parts of highway and railway networks.
Monitoring ground deformation over bridges and overpasses helps to understand their behavior over time and to detect degradation or subsidence risk at an early stage.
When monitoring deformation over bridges, mostly mid- and long-term deformation patterns are the most useful.
Therefore, seasonal deformation (thermal expansion and contraction) as well as punctual vibrations (caused by heavy trucks) have to be filtered out during the deformation analysis.
Radar satellite analysis allows us to measure deformation for bridges and overpasses in the past (from 1992 on) and in the present.
Dam failures can have a horrible impact on the environment as well as the population.
Concrete, earthen, or rock-filled dams are put at risk of failure by foundation subsidence. This can be caused by pressure changes of the water contained within the dam, seismic activity, or an unstable environment (e.g. landslides).
Monitoring subsidence provides an early warning of reduced dam safety and a record of structural health. Warning signs of dam failures are identified on the dam itself as well as in its surroundings.
Dam stability is monitored directly after construction to quantify dam settlement as well as during the entire dam lifecycle to anticipate failures ahead of time.
Ports and airports are key infrastructure elements for large urban cities. It is very important to monitor them in order to ensure long-term operability of. Monitoring of ports and airports is especially important when they are located in subsidence prone areas (seismic active areas, unstable geological ground, permafrost areas etc.)
Ports often are located on land claimed from the sea, in new areas with high risk of subsidence. Initial subsidence can be several meters, slowing down as time passes after land claiming.
Airports are always expanding with new and recently constructed areas. Monitoring ground deformation for airport areas is crucial for safety of operations, especially on the runway where millimetric changes might lead to fatalities.
Subsidence of a group of buildings (or even a single building) can be interesting when the building has a specific value (skyscraper or value due to historical importance) or when subsidence risk is high.
Since costs are decreasing for subsidence studies and radar satellite data are available partly for free, it makes sense, economically speaking, to measure subsidence over single buildings.
The methodology consists of first measuring building settlement, then deriving the maximum angular distortion, and finally defining the building limit states to identify structural risk level for each building.
Monitoring of buildings stability enables owners and construction companies to forecast, prevent and mitigate future buildings damages.