Cabadbaran Hydroelectric Power Project – Geotechnical Investigation for Detailed Engineering Design

Our contribution

Services provided

• 14 exploratory boreholes with a maximum depth of 32.50 meters
• 3 boreholes along the proposed dam axis
• 1 borehole at the proposed desander
• 1 borehole at the proposed surge tank
• 8 boreholes around the surge tank–powerhouse area and/or alignment
• 1 borehole at the proposed pipe bridge/gallery site
• 12 exploratory test pits along the conveyance alignment
• Test pit excavation up to 3 meters deep
• 15 Standard Penetration Tests (SPT)
• 9 in-situ packer permeability tests
• Soil classification – ASTM D2487
• Technical Capabilities:
• Specific gravity of soil solids – ASTM D854
• Soil moisture content determination – ASTM D2216-92
• Grain size analysis – ASTM D422
• Atterberg limits determination – ASTM D4318
• Unconfined compression testing of rock samples
• Approach:
• Review the proposed hydropower development layout and identify geotechnical investigation locations at the dam axis, desander, surge tank, powerhouse, pipe bridge/gallery, and conveyance alignment.
• Conduct exploratory borehole drilling at 14 designated locations to investigate subsurface soil and rock conditions, reaching a maximum depth of 32.50 meters.
• Excavate 12 test pits along the conveyance alignment to examine near-surface materials and document subsurface conditions.
• Perform 15 Standard Penetration Tests at designated powerhouse, pipe bridge, and surge tank locations to assess soil penetration resistance.
• Conduct nine packer tests within the weir and powerhouse areas to assess the permeability characteristics of subsurface rock formations.
• Collect representative soil and rock samples for laboratory classification and engineering property testing.
• Compile and evaluate field investigation findings and laboratory results to support the detailed engineering design of the proposed hydropower structures.
• Regulatory Context:
• The geotechnical investigation was undertaken to provide technical information supporting the detailed engineering design of the proposed Cabadbaran Hydroelectric Power Project.
• Laboratory testing included soil classification under ASTM D2487, specific gravity determination under ASTM D854, moisture content determination under ASTM D2216-92, grain size analysis under ASTM D422, and Atterberg limits determination under ASTM D4318, together with unconfined compression testing of rock samples.
• The investigation findings provide engineering inputs for evaluating subsurface conditions, foundation characteristics, and design considerations for the proposed dam and associated hydropower infrastructure.