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�r k Cdr �- .� 'L ��y1, ,.- w n . fi +: A :>✓.,` � '"P ti-�.` ?. 's`i5„ ..<�- a <br /> i <br /> �- 2,1.5 Qu£allty Control <br /> Quality control procedures include calibration of the electric friction cone, checking for <br /> and remediating probe defidencses, maximizing the safe achievable penetration depth, and <br /> deterring loss of the plezometric response (if applicable). The following paragraphs <br /> describe these procedures. <br /> Calibration of the electric friction cone probes is performed by imparting a series of <br /> known loads on the cone tip,fiction sleeve,and pore pressure transducer, and comparing <br /> the known loads with the output signals from the probe. Dev,aticns are corrected by <br /> adjusting the calibration settings of the DAS. The calibration is, conducted over the full <br /> _ range of the probe's output, but particular attention is devoted to the lower end of the <br /> measurement range, where any deviations tend to be more critical. Changes in the <br /> calibration constants of each probe are monitored over time to provide performance <br /> histories,which help determine replacemeat intervals. <br /> Calibrations spanning tha full range of measurements are conducted every 3,000 lineal feet <br /> of penetration. Zero-load readings of thu cone tip and sleeve friction are recorded <br /> before and after each test, while the prof:a is suspended vertically in the air. These <br /> readings provide a direct indication of the data quality. Significant non-zero outputs <br /> could result from mechanics! factors preventing proper load cell response, as well as <br /> instability or malfunction of the OAS or strain gauges. Previous overloading of the load <br /> cells or severe temperature fluctuations can also cause zero drifts. <br /> The cone tip and friction sleeve diameters are measured daily to monitor the wear due to <br /> - soil abrasion. These components are replaced when their dimensions drop below the ASTM ,k <br /> (1986) specified tolerances. The friction sleeve diameter is always larger than that of <br /> the cone tip, so as to avoid a tficially low friction sleeve readings. The roughness of <br /> the cone tip and friction sleeve surfaces are also monitored and maintained within ASTM <br /> specifications. The rubber fillers (quad rings) separating the cone tip and friction <br /> T sleeve from each other and the stationary parts of the probe (see Figure 2) ars:checked <br /> before each test, and replaced if necessary, to ensure correct load transfer from the cone <br /> tip and friction sleeve to the respective load cells. <br /> f 6 <br /> kit <br /> i <br /> 10 <br /> gin IN min HERE <br />