CAVU Aerospace UK Ltd

GeoTech survey with Space Data

Space data can complement geotechnical (geotech) investigations but cannot fully replace them, primarily because geotech involves subsurface analysis, which satellites cannot directly measure. However, space data provides valuable insights that enhance or inform geotechnical studies.

Here's a detailed breakdown

What Space Data Can Offer for Geotech

1. Surface Topography
– DEM/Digital Surface Models (DSM): Provides terrain elevations and features for preliminary site assessment.
2. Soil and Rock Type Estimation
– Spectral Imaging: Satellites like Landsat, Sentinel-2, and hyperspectral systems can identify soil and rock types based on their spectral signatures.
– Use Case: Preliminary identification of materials, erosion-prone areas, or geological structures.
3. Slope Stability and Landslide Analysis
– Synthetic Aperture Radar (SAR): InSAR can detect ground movement with millimeter accuracy, indicating slope instability or subsidence.
– Use Case: Early warning systems for landslides or monitoring of infrastructure like dams and roads.
4. Flood and Waterlogging Potential
– Hydrological Analysis: Space data aids in floodplain mapping, groundwater potential assessment, and surface water flow dynamics.
– Use Case: Identifying areas at risk of waterlogging before construction.
5. Seismic and Tectonic Activity Monitoring
– Deformation Monitoring: Satellite SAR tracks tectonic plate shifts and ground deformation caused by earthquakes or subsurface changes.
6. Vegetation and Land Use Analysis
– Land Cover Maps: Helps assess vegetation cover, which can influence soil stability and erosion.
7. Global Soil Moisture Data
– SMAP and Sentinel-1: Provide surface soil moisture levels, which are critical for understanding soil behavior.

What Space Data Cannot Do

1. Subsurface Analysis
– Soil Strength and Composition: Requires in-situ testing like Standard Penetration Test (SPT) or Cone Penetration Test (CPT).
– Stratigraphy: Space data cannot directly identify soil layers, groundwater tables, or bedrock depth.
2. Load-Bearing Capacity
– Space data cannot determine the mechanical properties of soil or rock, which are critical for foundation design.
3. Contamination Studies
– Detection of subsurface pollutants requires on-ground sampling and chemical analysis.
4. Site-Specific Customization
– Space data provides broad-scale information, but detailed geotech studies tailored to specific site requirements need localized, physical measurements.

Hybrid Approach: Enhancing Geotech with Space Data

While satellites cannot fully replace geotech investigations, they can enhance their efficiency and scope:

1. Site Selection:
– Use satellite data for preliminary screening to identify viable locations and eliminate unsuitable ones (e.g., flood-prone or unstable areas).
2. Risk Mitigation:
– Employ space-based deformation monitoring and seismic activity mapping to anticipate risks like landslides or subsidence.
3. Efficient Field Planning:
– Optimize fieldwork by using satellite-derived maps to pinpoint critical investigation zones.
4. Remote Monitoring:
– Monitor construction-induced ground movements or post-construction settlement using InSAR.

Applications of Space Data in Geotech-related Fields

1. Mining: Mapping ore deposits, monitoring ground deformation, and assessing slope stability in open pits.
2. Infrastructure Projects: Assessing terrain for highways, dams, and bridges.
3. Urban Planning: Identifying stable grounds for construction and monitoring ground subsidence in cities.
4. Disaster Management: Landslide susceptibility and monitoring post-earthquake ground deformation.
5. Agriculture: Soil moisture mapping and erosion potential assessment.

In brief, Space data cannot fully replace geotech investigations due to its inability to measure subsurface properties. However, it serves as a powerful tool for preliminary analysis, risk assessment, and monitoring, significantly improving the efficiency and scope of geotechnical projects. A hybrid approach, integrating space data with traditional geotech methods, is the most practical and effective solution.