Execute Dynamic Compaction Checklist

Definition: Execute dynamic compaction using this field checklist for contractors and inspectors, confirming grid layout, drop energies, crater backfilling, settlement monitoring, and acceptance per approved project specifications and authority requirements.

Confirms compaction grid, energy delivery, and drop sequence accountability.
Controls crater backfilling with density and moisture acceptance limits.
Tracks settlement trends to validate improvement and trigger escalation.
Interactive, commentable checklist with export and QR code for sign-off.

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Checklist

Execute dynamic compaction with a focused, field-ready checklist that aligns crews, validates grid spacing, and controls drop energy from start to acceptance. Also known as dynamic soil densification and drop weight ground improvement, this process relies on measured energy input, disciplined crater backfill, and systematic settlement monitoring to deliver uniform improvement. This checklist excludes foundations and concentrates solely on ground improvement execution within the designated treatment area. By standardizing grid confirmation, energy calculations, pass control, and density testing, it reduces risks of soft pockets, differential settlement, excessive vibration, and costly rework. Real-time documentation, photos, and readings create a defensible record for consultants and owners, supporting timely approvals. Use this interactive tool to tick tasks, attach comments, and capture evidence; then export as PDF/Excel with an embedded QR code for secure verification.

Provide a repeatable process for confirming grid layout, energy delivery, crater reinstatement, and settlement monitoring, ensuring predictable ground improvement outcomes and minimizing variability between shifts, crews, and rigs across changing soil conditions and weather windows.
Reduce rework and claims by defining measurable tolerances, drop counts, density targets, and monitoring intervals. Evidence-based decisions emerge from structured data: survey files, logger reports, test certificates, and photos anchored to coordinates and timestamps.
Interactive online checklist with tick, comment, and export features secured by QR code.
Accelerate acceptance by compiling a clean dossier of plans, approvals, energy logs, test results, and as-built surveys, enabling sign-off per approved project specifications and authority requirements without scope creep into foundations.

Pre-Works Verification

1. Confirm treatment limits exclude foundations and match IFC drawings; set out boundary with survey to ±0.10 m; capture geo-referenced photos and upload survey file (DWG/CSV).
2. Verify approved method statement and dynamic compaction plan (grid, passes, energy); record approvals and release hold point per approved project specifications and authority requirements.
3. Inspect crane, drop system, and tamper; confirm certification dates valid; weigh tamper (scale photo) to verify mass within ±2% of design.
4. Establish site control and QA survey; calibrate instruments; record atmospheric/temperature corrections; verify closure error ≤ 1:10,000; upload calibration report.

Compaction Grid Setup

5. Set out grid points at designed spacing (e.g., 3–6 m); check 10 random intervals within ±0.10 m; attach as-built file and point photos.
6. Create sequence plan and unique IDs for each grid point; post route map at rig and upload PDF to checklist.
7. Mark buried utilities and exclusion zones with fencing at ≥3 m offset; add utility mark-out sketch and locate scan report.
8. Install signage and barricades defining exclusion radius ≥1.5× drop height; photo verification each shift before works commence.

Energy and Drop Control

9. Confirm energy per drop E = m×g×h meets design within ±5%; record tamper mass (kN), height (m), and energy (kN·m) with calculations.
10. Fit drop counter and inclinometer; maintain verticality ≤ 1:100; log drops per point and export automatic logger file daily.
11. Control drop count per pass (e.g., 5–15); stop when rebound/penetration stabilizes; capture final drop count and rig operator sign-off.
12. Measure crater depth after each pass with survey staff; if depth exceeds design (e.g., >1.5 m) seek approval before continuing; record readings.
13. Observe rest/stand time between passes (≥1–2 h or per plan) to dissipate pore pressure; log start/stop times and ambient conditions.

Crater Backfill and Passes

14. Backfill craters with well-graded granular material; moisture at OMC ±2%; compact in 0.20–0.30 m lifts to ≥95% MDD; attach density and moisture test results.
15. Record backfill source, lot numbers, and delivery dockets; photograph materials and stockpiles; reject contaminated or oversize material.
16. Reinstate surface level at each point within ±20 mm of surrounding grade; verify with survey and upload level shots.
17. Apply dust suppression and manage runoff; maintain silt controls; document water usage (L) and weather; photo evidence of controls in place.

Settlement Monitoring

18. Install settlement plates or survey benchmarks before first pass; baseline to ±5 mm; record coordinates and photos of installations.
19. Survey settlement after each pass and at 24/48 h; compare to design envelope; trigger alert if deviation exceeds ±20%; escalate to engineer.
20. Monitor adjacent assets with seismograph and crack gauges; maintain PPV within project limits; attach PPV time history and inspection photos.
21. Update heatmap of drops, energy, and settlement by grid point; export daily dashboard (PDF/CSV) and share with stakeholders.

Acceptance and Documentation

22. Perform post-treatment tests (e.g., CPT/SPT/PLT) per plan; compare to acceptance thresholds; attach raw data, interpreted profiles, and locations.
23. Verify final surface RL matches design within ±30 mm; provide as-built survey (DWG/PDF) and coordinate list (CSV).
24. Compile dossier: approvals, daily reports, energy logs, density/moisture tests, settlement surveys, photos; obtain digital signatures (contractor/consultant/client) and archive.
25. Issue acceptance certificate per approved project specifications and authority requirements; close hold points and distribute final package.

Grid and Energy Control: The Core of Dynamic Compaction

A reliable outcome starts with a correctly established grid and verified compaction energy. Grid spacing governs overlap of influence zones; tight control (±0.10 m) reduces untreated pockets and improves uniformity. Energy delivery depends on tamper mass and drop height; verifying E = m×g×h within ±5% keeps the design intent intact across passes and shifts. Use a calibrated drop counter and inclinometer to maintain verticality and record every hit. Measure crater depth after each pass to confirm the soil response is within the expected envelope; excessive penetration may signal loose fills or organics requiring plan adjustments. Enforce rest times to dissipate pore pressure and allow settlements to manifest before subsequent passes. An on-rig sequence map with unique point IDs ensures systematic coverage and makes reconciliation with logs straightforward, producing traceable records for review and swift acceptance.

Hold grid spacing within ±0.10 m tolerance.
Calculate and log energy in kN·m per drop.
Maintain rig verticality to 1:100 or better.
Measure crater depth after each pass.
Use a sequenced, uniquely labeled grid.

Crater Backfill Done Right: Material, Moisture, and Density

Crater backfilling reinstates the surface and transfers energy effectively into the next passes. Select a clean, well-graded granular material; reject oversize or contaminated loads. Control moisture to the Optimum Moisture Content within ±2% to achieve compaction efficiently without pumping or segregation. Place in 0.20–0.30 m lifts and compact to at least 95% of Modified Proctor Maximum Dry Density, verified by field density tests. Document lot numbers, tickets, and stockpile photos to maintain material traceability. Trim the surface flush to surrounding grade within ±20 mm to support safe rig movement and accurate subsequent drops. Good backfill practice reduces rework, minimizes settlement scatter, and accelerates acceptance by proving that every pass is set up for success and that energy transfer is consistent across the grid.

Use clean, well-graded granular backfill.
Control moisture to OMC ±2%.
Compact lifts to ≥95% MDD.
Keep surface level within ±20 mm.
Record material lots and tickets.

Settlement Monitoring and Acceptance Pathway

Settlement behavior confirms soil densification and highlights areas needing attention. Establish settlement plates or survey benchmarks before the first pass and baseline them precisely. Measure after each pass and at 24–48 hours to capture delayed consolidation. Compare results against the design envelope; deviations beyond ±20% should trigger an engineering review, possible grid refinement, or additional passes. Protect neighboring assets by tracking vibrations with a seismograph and inspecting for cracking. Acceptance is built on objective evidence: energy logs, density/moisture results, settlement trends, and post-treatment tests such as CPT or SPT showing improved resistance. Finalize with an as-built surface survey and a consolidated dossier that stakeholders can review quickly. This disciplined monitoring and documentation route leads to confident approvals without drifting into foundation scope.

Baseline settlements before first pass.
Survey after each pass and at 24–48 h.
Escalate deviations exceeding ±20%.
Monitor PPV to protect adjacent assets.
Compile a complete acceptance dossier.

How to Use This Dynamic Compaction Checklist

Preparation: Gather approved plans, method statement, survey control data, logger setup, density/moisture test kits, PPE, barricades, and signage; brief the crew on grid, energy targets, passes, and safety zones.
Project setup: Create a checklist instance, enter grid spacing, pass counts, energy targets, tolerances, and required evidence types (photos, CSV, PDFs) to standardize field capture.
Using the Interactive Checklist: Start interactive mode on a tablet; tick tasks as completed, attach photos, upload survey/logger files, and record readings at each grid ID.
Collaboration: Tag responsible roles, leave time-stamped comments for clarifications, and request engineer approvals at defined hold points directly in the checklist.
Quality control: Review auto-flagged out-of-tolerance entries (e.g., energy ±5%, spacing ±0.10 m); create corrective actions and link them to affected grid points.
Export and sharing: Export the commentable record as PDF/Excel with an embedded QR code; share with stakeholders for daily reviews and sign-offs.
Sign-Off and Archiving: Collect digital signatures from contractor, consultant, and client; lock the record, store in the project archive, and reference the QR for audits.

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Elijah Johnson SmartGridElijah

Dec 18, 2025

115

FAQ

Question: How much compaction energy should we apply at each grid point?

Follow the geotechnical design. Compaction energy per drop is E = m×g×h, commonly resulting in 100–400 kN·m per blow depending on soil type and improvement target. Verify tamper mass and drop height each shift, record calculated energy, and adjust pass counts when penetration or settlement trends indicate diminishing returns.

Question: What is the best approach to crater backfill moisture and density control?

Use clean, well-graded granular backfill at Optimum Moisture Content within ±2%. Place in 0.20–0.30 m lifts and compact to at least 95% MDD (Modified Proctor). Confirm with field density and moisture tests at prescribed frequency. Reject wet, segregated, or contaminated material and record lot numbers and test results.

Question: How should settlement be monitored between passes and after treatment?

Install settlement plates or benchmarks before work, baseline them, and measure after each pass and at 24–48 hours. Compare to the design envelope; trigger escalation if deviation exceeds ±20%. Monitor adjacent assets using seismographs and crack gauges to ensure vibrations remain within project limits and no damage occurs.

Question: When can the treated area be accepted and released for subsequent works?

Acceptance follows evidence: energy logs within tolerance, density/moisture results meeting targets, settlement trending stable, and post-treatment tests (CPT/SPT/PLT) achieving design criteria. Provide an as-built surface survey and a complete dossier. Final sign-off is issued per approved project specifications and authority requirements.