| S.No. | Checkpoint | IS Requirement | Status |
|---|---|---|---|
| A. Geotechnical Investigation Phase | |||
| A1 | Geotechnical investigation report review — Verify report completeness: stratum profile, soil parameters (c, φ, γ, E), bearing capacity, settlement analysis, water table, founding recommendations Acceptance: Report dated and approved; stratum layers with thickness and description; SPT N-values; lab test results; bearing capacity calculation with factor of safety ≥3.0 for SBC; settlement ≤25 mm; founding depth and type recommended | IS 1892 Clause 7 (Report); IS 1904 Clause 2.2 (Investigation data) | OK NC NA HOLD |
| B. Excavation Phase | |||
| B1 | Excavation setting out — Verify pile/footing grid layout, RL bench marks, survey markers established Acceptance: Excavation perimeter marked with paint/chalk; RL bench marks fixed at ≥2 locations and verified by independent survey; offsets recorded from permanent structures; level of precision ±50 mm | IS 1904 Clause 10.1 (Setting out); IS 3764 Clause 5.2 (Preliminary work) | OK NC NA HOLD |
| B2 | Excavation depth/level verification — Final excavation level checked against design RL ±25 mm before PCC placement Acceptance: Survey level taken at ≥4 locations in pit; depth tolerance ±25 mm (e.g., design RL 100.00 m = 99.975 to 100.025 m acceptable); surface firm and level; no soft soil remaining; level report documented | IS 1904 Clause 3.1 (Foundation preparation); IS 3764 Clause 6.2 (Excavation) | OK NC NA HOLD |
| B3 | Bearing stratum verification — Geotechnical engineer inspects pit base; stratum type (color, consistency, SPT), bearing capacity adequate Acceptance: Geotechnical engineer on-site inspection; stratum matches bore log (e.g., 'dense sand, fine to medium, SPT N~35'); bearing capacity per geotechnical report confirmed adequate; rock socketing checked if required; approval certificate issued | IS 1904 Clause 3.2 (Approval of excavation); IS 1892 Clause 6 (Field identification) | OK NC NA HOLD |
| B4 | Shoring and slope stability — Daily inspection of temporary support (if any), slopes within IS 3764 Table 1 limits, no signs of failure Acceptance: Slopes (if any) follow IS 3764 Table 1 angles (1H:1V for clay, 1H:1.5V for sand); props and lagging inspected daily for cracks, bowing >50 mm not acceptable; settlement/inclinometer data reviewed; daily inspection log maintained | IS 3764 Clause 7 (Support systems); IS 3764 Clause 9 (Monitoring) | OK NC NA HOLD |
| B5 | Dewatering adequacy — Water level maintained ≥500 mm below working level; sump pump functioning, no flooding Acceptance: Daily water level measurement from standpipes; level ≥500 mm below excavation base (e.g., base at RL 100 m, water ≤100.5 m); pump capacity adequate for inflow; sump pit clean; discharge location noted | IS 3764 Clause 8 (Dewatering management); IS 1904 Clause 4 (Groundwater) | OK NC NA HOLD |
| B6 | PCC blinding placement — Grade M10, thickness ≥75 mm, level surface, test cubes taken Acceptance: PCC M10 (or per design); thickness ≥75 mm verified at ≥4 locations; surface level ±20 mm; cubes cast (1 set per 50 m²); curing for 7 days before loading; strength test results ≥10 MPa at 7 days | IS 456 Clause 11 (Foundation concrete); IS 1904 Clause 3.2 (Blinding) | OK NC NA HOLD |
| C. Backfill and Compaction | |||
| C1 | Backfill material approval — Grading per IS 2720 Part 4, free from organics, clay fines <15% (for granular backfill) Acceptance: Material grading checked (sieve analysis per IS 2720 Part 2); no organic matter, roots, or debris; clay fines <15% for sand/gravel backfill; approved source documented; material sample retained | IS 2720 Part 4 (Grain size analysis); IS 1904 Clause 5 (Backfill) | OK NC NA HOLD |
| C2 | Compaction testing — Field density test per IS 2720 Part 28 (sand replacement) or Part 29 (core cutter); ≥95% Modified DD (MDD) Acceptance: Field density test (sand replacement or core cutter) per layer (300 mm lift typical); density ≥95% MDD; moisture content within ±2% of optimum (from lab proctor test); test results documented per location | IS 2720 Part 28/29 (Compaction testing); IS 1904 Clause 5.2 (Compaction control) | OK NC NA HOLD |