Verify Bore Clean-Out: Sediment, Cleanliness, Tremie Ready

Definition: Verify bore clean-out helps inspectors measure sediment thickness, confirm base cleanliness, and assess tremie readiness for bored piles prior to concrete placement, ensuring consistent quality control without covering drilling parameters.

Measure sediment thickness at multiple locations to verify acceptance limits.
Confirm base cleanliness and absence of loose debris before concreting.
Check tremie assembly, sealing, and embedment planning for uninterrupted pour.
Interactive, commentable, export options with QR code verification.

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Checklist

Verify bore clean-out is a targeted quality-control step that confirms sediment thickness, base cleanliness, and tremie readiness for bored piles. This borehole cleanout verification focuses strictly on the final cleanliness of the base and the practical readiness of the tremie system prior to concrete placement. It excludes drilling parameters, tooling, and slurry or polymer design controls. By methodically measuring sediment thickness at several points, documenting base condition, and checking that the tremie pipe is clean, sealed, and able to remain embedded, you reduce risks of soft bases, inclusions, and post-pour defects. The outcome is a uniform, sound pile base that supports durable structural performance. This checklist guides inspectors, site engineers, and foremen to capture evidence with photos, measurements, and approvals aligned with approved project specifications and authority requirements. Use the interactive features to tick off steps, add comments, and export your record as PDF/Excel with an embedded QR for fast retrieval.

Confirm bore base cleanliness and sediment thickness using repeatable methods such as weighted tapes and flat plates. Capture photos, timestamps, and instrument IDs so your records show what was measured, where, and when—all aligned with approved project specifications and authority requirements.
Reduce defects by validating the base is free of loose cuttings and debris, and that measured sediment thickness is within project limits. Re-clean and re-measure if thresholds are exceeded, then document the corrective cycle to close quality loops before any concrete is placed.
Verify tremie readiness without touching drilling parameters: check internal cleanliness, joint gaskets, watertightness, plug fit, and embedment planning. A short dry run confirms alignment and reach, minimizing delays and ensuring uninterrupted tremie placement once concreting starts.
Interactive online checklist with tick, comment, and export features secured by QR code. Instantly attach photos, sign digitally, and share acceptance status with stakeholders. Export as PDF/Excel and archive with unique QR authentication for traceable, tamper-evident project records.

Pre-Verification Safety & Access

1. Establish an exclusion zone around the bore with barriers and signage; verify the permit-to-work is active. Acceptance: zone established and permit valid. Evidence: photo of setup and recorded permit ID/time.
2. Confirm safe access: stable platform, guardrails, fall protection, tool lanyards. Acceptance: platform rated and inspected today. Evidence: photo of platform tag and supervisor initials.

Measurement Tools Calibration & Setup

3. Check weighted tape/sounding rod against a certified steel rule. Acceptance: length accuracy within ±5 mm over 10 m. Evidence: calibration photo and certificate number.
4. Verify flat plate sediment disk (150–300 mm diameter) is flat, clean, and labeled with instrument ID. Acceptance: no warping or damage. Evidence: photo with scale and ID.
5. Function-check echo-sounder/depth logger (if used) in a known-depth tank. Acceptance: reading within ±5 mm at 1.00 m; battery >50%. Evidence: screenshot/readout and test setup photo.
6. Tag all instruments with unique IDs and log them in the checklist. Acceptance: IDs recorded for traceability. Evidence: instrument list saved to record.

Bore Base Cleanliness Verification

7. Lower a transparent bailer/core sampler to ~0.5 m above base; retrieve a sample. Acceptance: sample free of debris/organics; turbidity per approved project specifications. Evidence: photo of sample against reference scale.
8. Use a downhole camera or illuminated mirror (when safe/dry) to view the base. Acceptance: no loose cuttings, cobbles, or laitance. Evidence: photos/video of base condition.
9. Record the time since last clean-out and method used (airlift/pump). Acceptance: verification conducted within the project’s allowable window. Evidence: log entry with method and timestamp.

Sediment Thickness Measurement

10. Measure depth to firm base with a weighted tape until firm contact is felt. Acceptance: repeat reading within ±10 mm. Evidence: photo of tape reading and timestamp.
11. Gently lower the flat plate disk; note depth where it rests on soft sediment. Calculate sediment thickness = (soft surface depth − firm base depth). Acceptance: thickness within project limit (record mm). Evidence: calculation in log.
12. Repeat sediment measurement at four locations 90° apart using a positioning template or marked cage. Acceptance: each point within limit. Evidence: sketch/grid with point readings.
13. For bores >1.2 m diameter, include a center reading and additional quadrants. Acceptance: maximum recorded thickness within limit. Evidence: tabulated results highlighting maximum.
14. If any reading exceeds the limit, require re-clean-out and re-measure all points. Acceptance: all re-measurements within limit. Evidence: nonconformance record and closure sign-off.

Tremie Readiness Checks

15. Inspect tremie pipe interiors for cleanliness; check gaskets/clamps; assemble and hold a 1.0 m water head for 5 min. Acceptance: leak-free joints. Evidence: photos and test time noted.
16. Confirm tremie internal diameter versus mix aggregate size. Acceptance: compliance per approved project specifications. Evidence: caliper measurement photo and mix design reference.
17. Verify planned tremie length and embedment so the tip remains immersed during placement. Acceptance: embedment per approved project specifications. Evidence: length calculation sheet attached.
18. Check start plug/foam pig and bottom valve/trumpet shoe fit. Acceptance: plug intact, correct diameter, free movement. Evidence: component photos with dimensions.
19. Perform a dry run lowering the tremie to 100–200 mm above the base without contact. Acceptance: vertical alignment; no kinks or obstructions. Evidence: photo/video and supervisor initials.

Documentation & Acceptance

20. Upload measurements, photos, and approvals; set status Accept/Reject with rationale. Export PDF/Excel and apply QR. Acceptance: complete, traceable record. Evidence: exported file link and QR screenshot.

Why bore clean-out verification matters before tremie placement

Clean-out verification ensures a sound base for tremie concrete, minimizing soft spots, laitance inclusions, and repair risk. The focus is narrow and practical: measure sediment thickness, confirm base cleanliness, and prove tremie readiness—without touching drilling parameters. This discipline protects load transfer at the pile base and reduces defects that are costly to remediate. By using simple, repeatable methods (weighted tapes, flat plates, bailers, and optional cameras), crews capture objective evidence. Acceptance is defined by project specifications and authority requirements, typically expressed as maximum allowable sediment thickness and a clean, debris-free surface. Verifying readiness also addresses the tremie’s ability to start watertight and remain embedded, preventing segregation during the pour. Real-world examples show that a few millimetres of extra sediment can markedly reduce base resistance; timely re-clean and re-measure avoids that outcome. The result is a confident green light for concreting with thorough, traceable documentation.

Limit verification to sediment, cleanliness, and tremie readiness.
Capture repeatable measurements with instrument IDs and timestamps.
Use photos/video to document base condition objectively.
Trigger re-clean and re-measure if limits are exceeded.

Practical methods to measure sediment thickness and cleanliness

A reliable sequence is: establish safety, validate instruments, take a base sample, then measure depths. Weighted tapes determine firm base depth; flat plate disks indicate the soft sediment top. Subtracting these values yields thickness in millimetres. Take multiple readings around the circumference and at the centre for larger diameters. Bailer samples and optional downhole cameras give objective views of cleanliness. Acceptance criteria come from the approved project specifications; record them in the checklist alongside your measured values. Repeat any measurement with a variance greater than the allowed repeatability, and document both attempts. If any location exceeds the sediment limit, require re-clean-out via airlift or pumping, then re-measure all points. This closed-loop approach prevents isolated nonconformances from slipping through and ensures the entire base meets the same standard before authorization to pour.

Measure firm base and soft surface depths independently.
Record at least four circumferential points; add center on large bores.
Re-clean and re-measure if any point exceeds limits.
Attach photos of instruments, readings, and sample clarity.

Proving tremie readiness without mixing in drilling parameters

Tremie readiness is about the equipment and the start sequence, not slurry design. Inspect pipe interiors, joints, and seals; assemble and hold a small water head to confirm watertightness. Verify the diameter against the aggregate size per the approved project specifications, and plan the initial embedment so the tremie tip stays immersed throughout the pour. A brief dry run confirms reach and alignment while staying above the base to avoid disturbance. Check the start plug or foam pig fits correctly and moves freely. These checks prevent washouts, cold joints, and flow interruptions during placement. Close by consolidating all evidence—photos, measurements, calculations, and sign-offs—into a single, traceable record so authorization to pour is defensible and auditable later.

Leak-check assembled tremie for watertight joints.
Confirm internal diameter against mix aggregate size.
Plan and record tremie embedment calculations.
Dry-run placement to confirm alignment and reach.

How to Use This Bore Clean-Out Verification Checklist

Preparation: Gather weighted tape, flat plate disk, transparent bailer, optional camera, PPE, and tremie components. Brief the team on scope: sediment thickness, base cleanliness, tremie readiness—no drilling parameters.
Open the interactive checklist on your device and enter project, bore ID, and instrument IDs. Set acceptance limits per approved project specifications and authority requirements.
Perform measurements and observations in sequence. Tick each item, attach photos/videos, and add comments to clarify locations, depths, and time since clean-out.
Review results against acceptance criteria. If any point exceeds limits, raise a nonconformance, trigger re-clean, and re-measure until compliant.
Sign-Off: Capture digital signatures from the inspector and contractor representative. The system time-stamps and locks entries for traceability.
Export and Archive: Export the record as PDF/Excel, auto-generate a QR, and share with stakeholders. Store the file and QR for audit retrieval.

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Miguel Garcia GeoMiguel

Jan 06, 2026

249

FAQ

Question: How much sediment is acceptable at the bore base before tremie concreting?

Acceptance limits are defined per approved project specifications and authority requirements. Many projects use a maximum sediment thickness threshold at multiple locations. Measure firm base and soft surface depths, calculate the thickness in millimetres, and accept only if all points are within the stated limit.

Question: What if I cannot visually inspect the base due to fluid conditions?

Use objective methods: bailer samples taken ~0.5 m above the base, flat plate depth measurements, and, where feasible, echo-sounder readings. Combine multiple lines of evidence. If clarity is inadequate to confirm cleanliness, require additional clean-out and re-measure until evidence supports acceptance.

Question: Do I need an echo-sounder, or is a weighted tape sufficient?

A weighted tape and flat plate disk are usually sufficient for measuring firm base and soft surface depths. An echo-sounder can supplement or cross-check readings, especially in large diameters. In all cases, verify instrument calibration and document repeatability before accepting measurements.

Question: When should I take measurements relative to final clean-out?

Measure promptly after the final clean-out, within the project’s allowable window, to limit re-sedimentation. Record the time since clean-out and method used. If delays occur or readings exceed limits, instruct re-clean and re-measure before authorizing tremie concreting.

Question: What documentation is required to approve the bore for concreting?

Provide instrument IDs, depth readings, calculated sediment thickness at all points, base condition photos or video, tremie leak check evidence, embedment calculations, and digital signatures. Export the checklist as PDF/Excel with a QR code to ensure traceability and quick audit retrieval.