Drone Mapping for Geotechnical Investigation and Slope Monitoring

Geotechnical engineering often involves working in difficult, hazardous terrain — steep slopes, unstable ground, and active landslides. Traditional investigation methods require field crews to access these areas, creating safety risks and limiting the scope of investigation.

Drone mapping is changing this. High-resolution imagery and precise terrain data can be collected from a safe distance, providing geotechnical engineers with the information they need without putting field crews at risk.

Rock faces — natural cliffs, cut slopes, and quarry walls — are challenging to characterize with traditional methods. Accessing a steep rock face for detailed mapping requires rope access or scaffolding — expensive, time-consuming, and potentially dangerous.

Drone photogrammetry can produce a detailed 3D model of a rock face from a safe distance. This model supports:

• Discontinuity mapping — identifying joints, faults, and other structural features
• Rock mass classification — characterizing rock mass quality for engineering design
• Kinematic analysis — assessing the potential for planar, wedge, or toppling failures
• Volume estimation — estimating the volume of potentially unstable rock

For soil slopes — natural hillsides, embankments, and cut slopes — drone mapping provides:

• Slope geometry — precise measurement of slope angles, heights, and extents
• Surface condition — documentation of erosion, seepage, and vegetation conditions
• Failure feature mapping — identifying tension cracks, scarps, and other failure indicators

Active landslides move continuously or episodically. Monitoring this movement is essential for understanding the hazard and managing the risk. Drone surveys at regular intervals — monthly, quarterly, or after significant rainfall events — document surface deformation:

• Surface displacement — comparing DEMs from successive surveys to measure movement
• Crack development — documenting the development and widening of tension cracks
• Scarp progression — tracking the upslope progression of the failure scarp

This monitoring data supports hazard assessment, early warning systems, and engineering design for stabilization.

Embankments and dams are critical infrastructure that require monitoring for deformation. Drone surveys can detect subtle surface changes — settlement, lateral movement, and cracking — that may indicate developing problems.

For large embankments where traditional survey monitoring is impractical, drone surveys provide comprehensive coverage at reasonable cost.

Open pit mine walls are subject to slope instability. Drone surveys can monitor pit wall conditions, detecting movement or deterioration before it becomes a safety hazard.

When a slope failure occurs — landslide, embankment failure, rock fall — drone mapping provides rapid documentation of the failure:

• Failure geometry — the extent, depth, and volume of the failure
• Failure mechanism — evidence of the failure mode (rotational, translational, flow)
• Runout — the extent of debris deposition
• Infrastructure damage — damage to roads, buildings, and utilities

This documentation supports forensic investigation, insurance claims, and design of remediation measures.

Many geotechnical investigation sites are in difficult terrain — steep slopes, dense vegetation, or active construction areas. Drone mapping provides data from these sites without requiring field crew access:

• Remote sensing — collecting data from a safe distance
• Hazardous areas — documenting conditions in areas too dangerous for field crews
• Active construction — collecting data without disrupting construction operations

Drone mapping data integrates with standard geotechnical analysis tools:

• Slope stability analysis — using drone-produced terrain data as input for stability models
• Kinematic analysis — using rock face mapping data for discontinuity analysis
• Numerical modeling — using 3D terrain models as input for finite element and discrete element models

Drone mapping is a valuable tool for geotechnical engineers working in difficult terrain. The ability to collect detailed spatial data from a safe distance — and to monitor deformation over time — makes drone surveys an essential complement to traditional geotechnical investigation methods.

Contact Blackridge Geospatial to discuss drone mapping services for your geotechnical project.