Flow Chart - Construction of Embankment & Subgrade

flowchart TD A(["Start"]) --> B["Checking of Original Ground Level\nBy Contractor & CSC"] B --> C{"Is soil clayey / black / marshy?"} C -- Yes --> D["Remove & replace with suitable material"] D --> E["Check levels\n(tolerance ±25 mm for embankment base)"] E --> F{"Levels OK?"} F -- No --> E F -- Yes --> G["Approved borrow earth"] C -- No --> G G --> H["Watering and loosening earth surface\nwith sprinkling"] H --> I["Rolling 8–10 passes\n(+2% to -1% of OMC)"] I --> J["Field moisture content test"] J --> K{"Rolling at OMC ±2%?"} K -- No --> H K -- Yes --> L["Field density test (FDT)"] L --> M{"Meets required density?\n(≥97% embankment / ≥98% subgrade)"} M -- No --> H M -- Yes --> N["Check levels\n(tolerance ±25 mm / ±15 mm)"] N --> O{"Field dry density ≥ required % of MDD?"} O -- Yes --> P["Approve layer for next lift"] O -- No --> H P --> Q["Check CBR at MDD & OMC"] Q --> R{"CBR ≥ required value?"} R -- No --> S["Sieve analysis\n + Atterberg limits\n + Classification"] S --> T{"Soil satisfactory?"} T -- No --> D T -- Yes --> U["Ready for next layer"] R -- Yes --> U U --> V["Spread next layer\n(≤ 250 mm thick)"] V --> H U --> W(["End"]) %% styling classes (Mermaid supports classDef) classDef process fill:#e7f0fd,stroke:#4682b4,stroke-width:1px; classDef decision fill:#fff5b7,stroke:#b8860b,stroke-width:1px; classDef action fill:#d4f8e8,stroke:#2e8b57,stroke-width:1px; classDef remove fill:#fcd5ce,stroke:#d22b2b,stroke-width:1px; class A,B,G,H,I,J,L,N,P,Q,U,V process; class C,F,M,O,R,T decision; class D,S remove;