Pressure to Alter a Stockpile Report
Late Friday, a contractor's superintendent asks you to reissue a soils report for retaining-wall backfill. The original report states that the sample from the stockpile had 38% passing the No. 200 sieve and a PI of 16, which fails the specification limit of PI 12. The superintendent says the sample was taken from the top of the stockpile, which had fines from rain washing, and offers a new sample from the "good part" of the stockpile. He also asks you to change the sample location on the report to "random stockpile sample" so the owner will not reject the pile, and to backdate the report to before wall backfill started. You are the technician who collected the original sample. Your field log says the sample was from the north face, 2 ft below the top, and the report is accurate.
1. How should you respond to the requests to change the sample location and backdate the report?
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I would refuse both requests. Changing the documented sample location would falsify the record, and backdating the report would misrepresent when the test result was available. My field log shows the sample was 2 ft below the top of the north face, not at the surface, so the superintendent's premise does not match the record. The original report is accurate and should not be altered. If a new sample is taken, it must be a new report with its own sample identification, location, date, and results. I would explain the refusal to the superintendent, notify my supervisor, and keep the original field notes and report unchanged. The owner or engineer can then decide acceptance based on truthful information.
2. Is the superintendent's claim about rain-washed fines technically plausible, and how would you investigate it without altering the original report?
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The claim is plausible in a general sense: stockpiles can segregate, and rainfall can wash fines downward or create a fine-rich crust. But plausibility does not justify changing an existing sample location or suppressing a failing result. The correct response is to investigate variability. I would collect a properly composited sample from multiple locations and depths around the stockpile, log each location, and split the sample with the contractor. The new sample should be tested for gradation and Atterberg limits, and the results compared with the original. If the new composite passes, the report should show both sets of results and note the variability; it should not rewrite the first sample. Additional random sampling may be needed before the engineer accepts the pile.
3. What should a defensible reissued or supplemental report contain?
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A defensible supplemental report should identify the project, the sample identification, the exact sampling location and depth, the sampling date and method, the testing standards, and the results. It should compare the results with the specification limits and state clearly whether the sample passes or fails. It should reference the original report and explain why the additional sample was taken, without changing the original data. The report should include the limitations of a stockpile sample, the chain of custody, and the name and signature of the responsible technician or engineer. If the original report is reissued for format reasons, it should be marked as a new revision with a new date, not backdated. Any communication with the contractor about the failing result should be factual and documented.