Correct Subgrade — Verification
Define the finished purpose, reference levels, underlying material condition and the evidence required by the receiving operation. Geometry alone does not establish structural or agronomic performance.
This reference assembles relevant extracts from the guide library. It is general project planning, not a local project report, verified specification or translated technical publication.
Uneven Subgrade
Uneven subgrade can create variable thickness in every layer above it. Correcting the surface is useful only if the underlying support is acceptable.
Before moving material
Identify soft areas and compare formation levels with design.
Receiving operation and checks
Complete compaction and specified acceptance checks. Check levels before base material conceals the subgrade.
A scraper does not replace proof testing or project-specific investigation.
Read the complete Uneven Subgrade guideHow to Prepare Subgrade for Road Base
Before road base is placed, the subgrade should be accepted for both level and condition. An uneven or weak supporting surface can lead to thickness variation and premature failure above it.
Before moving material
Confirm formation level and identify unaccepted areas.
Receiving operation and checks
Inspect and accept before spreading base aggregate. Record level and material checks for the same work area.
Adding more base material is not automatically a remedy for weak subgrade.
Read the complete How to Prepare Subgrade for Road Base guideWhat Verification Evidence Proves
Verification evidence should answer the acceptance question asked. Elevation measurements establish geometry; material records and relevant tests address layer condition. Neither should be silently substituted for the other.
Before moving material
Define the checks needed for the finished purpose.
Receiving operation and checks
Hand over accepted areas and clearly identify exceptions. Check that the evidence concerns the same layer and work zone.
An instrument display is not a complete acceptance record.
Read the complete What Verification Evidence Proves guideRecord the job inputs
Use this checklist to turn the scenario into a specific brief. Retain the design revision and agree who accepts each completed layer.
Checklist ticks apply only while this page is open. Include the completed brief in your project records.
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