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Detail stage: bridge and reservoir

Short answer

For bridges, the detail stage includes boreholes at each pier and abutment, geophysical profiles for bedrock depth, in-situ tests for bearing capacity, and scour assessment. For reservoirs, it involves rim mapping, core drilling with Lugeon permeability tests, slope stability analysis, and evaluation of leakage paths and sedimentation.

Describe the details stage of engineering geological site investigation of bridge and reservoirs.

The detail stage gives the exact ground data needed for design after the bridge site or reservoir has been selected.

Bridge

  • Large-scale mapping of both banks and the river bed.
  • Boreholes at every pier and abutment position, and core drilling at least 3 m into sound rock; SPT in soil; undisturbed samples.
  • Geophysical profiles across the river for bed rock depth.
  • In-situ and laboratory tests for bearing capacity, shear strength, and permeability.
  • Study of scour depth, flood levels, bank stability, and river training needs.
  • Seismic and liquefaction assessment; materials for aggregate and fill.

Reservoir

  • Detailed mapping of the reservoir rim, dam and abutments, with special attention to leakage paths: faults, solution cavities in limestone, permeable layers, and low saddles in the rim.
  • Core drilling and water-pressure (Lugeon) tests to get permeability of foundation and rim.
  • Groundwater table, springs and water divide study.
  • Slope stability of reservoir banks and landslides which may enter the reservoir.
  • Sedimentation estimates and silt load.
  • Seismic study (reservoir-induced seismicity) and construction material survey.

✓ Answer checked by Claude Opus 5.5 (high effort)

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