Geotechnical Investigation and Slope Stability Analysis
Jimma-Chida Road Project
- Desk Study and Preliminary Assessment
- Collected and reviewed all available geological, topographical, and geotechnical data relevant to the road corridor.
- Interpreted aerial photographs, satellite imagery, and existing maps to identify geomorphological features and potential slope instability zones.
- Conducted a site walkover survey to observe surface conditions, drainage patterns, vegetation cover, signs of distress, and historical slope failures.
- Detailed Geotechnical Investigation
- Borehole Drilling and Test Pits: Subsurface conditions were investigated through strategically located boreholes and test pits to identify soil and rock stratigraphy, groundwater conditions, and the depth of weathering.
- Sampling and Laboratory Testing: Representative soil and rock samples were collected and tested to determine key engineering properties such as shear strength, unit weight, cohesion, angle of internal friction, Atterberg limits, and permeability.
- In-Situ Testing: Performed field tests such as Standard Penetration Test (SPT), Cone Penetration Test (CPT) to evaluate in-place strength parameters and consistency of soils.
- Slope Geometry and Material Characterization
- Surveyed slope geometry using total station and drone-based photogrammetry to generate accurate slope profiles and cross-sections.
- Characterized materials along the slope—differentiating between colluvium, residual soils, weathered rock, and intact rock—to define engineering zones and interfaces.
- Groundwater and Drainage Assessment
- Identified seepage zones and shallow groundwater conditions that could affect slope behavior.
- Assessed the adequacy of existing drainage systems and potential impacts of water infiltration on slope stability.
- Slope Stability Analysis
- Developed geotechnical models for representative slope sections using appropriate analytical and numerical methods.
- Conducted both limit equilibrium analysis (Morgenstern-Price methods) and numerical modeling (FEM ) where complex ground conditions required more detailed simulation.
- Evaluated Factor of Safety (FoS) for various slope configurations under static and seismic loading conditions.
- Assessed the impact of road cuts, embankments, and potential loadings on slope performance.
- Stabilization and Design Recommendations
- Identified sections requiring stabilization
- Proposed suitable mitigation measures, such as:
- Regrading or flattening slopes
- Installation of retaining structures (gabion walls, reinforced earth)
- Drainage improvement (surface drains, sub-horizontal drains)
- Reinforcement techniques (soil nails)
- Provided design parameters and construction guidelines for slope protection works.
- Reporting and Documentation
- Prepared a detailed geotechnical investigation report, including test results, slope stability analyses, and engineering recommendations.
- Included maps, cross-sections, and stability charts to support design decisions and inform construction planning.
Geomechanical & Geotechnical Studies – Discontinuity Mapping, Settlement Identification, and Remedial Measures
Gondar Fasiledas Conservation Project
- Discontinuity Mapping and Analysis
- Field Survey and Geological Mapping: conducted detailed structural mapping of exposed rock faces, surfaces, and buildings within the conservation area to identify and record all relevant discontinuities, including joints, bedding planes, foliations, and fractures.
- Measurement and Characterization: Key parameters such as orientation (dip and dip direction), spacing, persistence, roughness, aperture, infilling material, and weathering conditions were measured and documented.
- Kinematic Analysis: using stereographic projection techniques, performed kinematic assessments to evaluate potential failure mechanisms (e.g., planar, wedge, toppling) in relation to slope geometry and discontinuity orientations.
- Settlement Identification and Assessment
- Visual Inspection and Monitoring: identified surface signs of settlement including cracks in masonry, tilting structures, ground depressions, and displacement of blocks or stone elements.
- Subsurface Investigation: used data from geophysical investigations
- Historical Comparison: compared current deformation patterns with archival data, historical images, or previous survey records to understand the progression of settlement phenomena over time.
- Remedial Measures Recommendations. Based on the findings of the geomechanical/geotechnical assessment, site-specific stabilization and conservation recommendations were developed, including:
- Structural Stabilization
- Installation of rock bolts or anchors to reinforce unstable rock blocks or fractured masses.
- Use of tie rods, buttresses, or stainless-steel anchors in heritage masonry to counteract displacement or separation.
- Surface Protection
- Application of compatible grouting to fill open joints and stabilize fragmented sections without compromising heritage value.
- Use of protective mesh or netting in rockfall-prone zones.
- Ground Improvement
- Compaction grouting or underpinning of foundations where differential settlement was observed.
- Installation of micro-piles or soil nails to enhance bearing capacity and control settlement in weak or loose ground.
- Drainage and Water Control
- Improvement of surface and subsurface drainage to reduce water ingress that could trigger instability or accelerate settlement.
- Diversion of runoff from sensitive areas through gutters or perimeter drains.
- Monitoring and Maintenance Plan
- Development of a long-term monitoring and maintenance plan including periodic inspections, instrumentation checks, and condition assessments to track the performance of remedial measures and respond to new risks.
- Structural Stabilization
Geotechnical Study – Alternative Transportation Solutions (Underground Crossings and Underground Terminals)
Piassa-Megenagna-Bole-Arat Kilo Corridor Development Project
- Preliminary Site Assessment and Data Collection
- Conducted a comprehensive desk study compiling existing geological maps, utility records, topographic data, and prior investigations within the corridor.
- Identified feasible zones for underground solutions through alignment studies, taking into account land use, environmental constraints, urban density, and projected transportation demand.
- Geological and Geotechnical Investigation
- Feasibility Analysis for Underground Transportation Structures
- Assessed the geotechnical feasibility of proposed underground solutions
- Geotechnical Risk Identification and Mitigation Planning
- Identified geohazards such as soft ground, fault zones, high water table, swelling/shrinkage soils, and ground contamination.
- Development of Alternative Engineering Solutions. Based on the geotechnical findings, multiple underground infrastructure alternatives were proposed
- Shallow vs. Deep Underground Terminals
- Cut-and-Cover vs. Bored Crossings
- Provided geotechnically informed decision support tools to stakeholders to optimize route alignment and infrastructure type.
- Reporting and Integration into Corridor Development Master Plan
- Produced a detailed geotechnical report summarizing all investigation findings, engineering analyses, and design recommendations.
- Ensured that the proposed underground solutions were fully integrated into the broader transportation and urban development strategy of the Piassa-Megenagna-Bole-Arat Killo Corridor.
Geotechnical Investigation – Geological and Structural Mapping, Strata Modeling, Fault Zone Identification, and Remedial Measures Recommendations
Ayat Kazanchis Private Public Partnership Project
- Geological and Structural Mapping
- Conducted detailed surface geological mapping across the project footprint to identify and record the distribution of rock types, weathering patterns, and structural features.
- Structural Mapping involved systematic identification and measurement of discontinuities such as joints, bedding planes, faults, folds, shear zones, and fracture systems.
- Mapped features were digitized and integrated into a GIS environment for spatial correlation with project components (e.g., alignment, structures, utilities).
- Subsurface Stratigraphic Modeling (Strata Modeling)
- Developed a 3D geological model of the subsurface using borehole logs, geophysical survey data, and outcrop information to represent the vertical and lateral variation of soil and rock layers.
- Stratigraphic units were interpreted and correlated across the site, allowing for the accurate delineation of:
- Lithological boundaries
- Interfaces between soil and bedrock
- Depth of competent strata suitable for foundations
- The model served as a critical input for design planning, construction method selection, and geohazard risk evaluation.
- Fault Zone Identification and Characterization
- Mapped fault zones within the project area through integration of field data, desktop study, and regional tectonic studies.
- Assessed fault characteristics including:
- Width and orientation of fault zones
- Nature of fault gouge and damage zone materials
- Evidence of recent activity (e.g., surface rupture, offset features)
- Evaluated the seismic and geotechnical implications of fault proximity, including potential for ground rupture, differential settlement, and shear displacement.
- Remedial Measures Recommendations. Based on the identified geological and structural risks, remedial and mitigation measures were recommended to ensure safe, cost-effective, and resilient project development:
- For Fault-Affected Areas:
- Realignment of structures and infrastructure to avoid surface fault rupture zones where feasible.
- Design of flexible foundation systems or seismic joints for structures intersecting fault zones.
- Reinforcement of subgrade materials using deep foundation systems, ground improvement, or geosynthetics in shear-prone areas.
- For Unfavorable Strata and Weak Zones:
- Ground improvement techniques such as grouting, jet grouting, or deep soil mixing.
- Excavation stabilization through temporary supports and staged construction.
- Reporting and Integration with Engineering Design
- A comprehensive geotechnical report was prepared summarizing:
- Geological and structural maps
- Borehole and lab test data
- 2D/3D strata models
- Fault hazard zones and risk ratings
- Engineering recommendations and mitigation strategies
- The geotechnical findings were integrated with design teams and stakeholders to inform safe foundation design, and construction planning under the Private Public Partnership (PPP) framework.
- A comprehensive geotechnical report was prepared summarizing:
More Accomplishments
Geomechanical Study – Anchor Spot Selection Based on Geomechanical Analysis
In addition, for various projects, comprehensive geomechanical investigation, involving detailed geological and structural mapping, field and laboratory testing, in-situ stress measurement and monitoring, numerical modeling as well as anchor spot selection based on geomechanical analysis was performed.
