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1 <br /> cT" ConeTec <br /> t �■ Geotechnical and Environmental Site Investigation Contractors <br />' ConeTec CPT Interpretations as of January 7, 1999 (Release 100 19) <br />' ConeTec's interpretation routine should be considered a calculator of current published CPT correlations <br /> and is subject to change to reflect the current state of practice The interpreted values are not <br /> considered valid for all soil types The Interpretations are presented only as a guide for geotechnical use <br /> and should be carefully scrutinized for consideration in any geotechnical design Reference to current <br />' literature is strongly recommended <br /> The CPT Interpretations are based on values of tip, sleeve friction and pore pressure averaged over a <br /> user specified interval (typically 0 25m) Note that Qt is the recorded tip value, Qc, corrected for pore <br /> pressure effects Since all ConeTec cones have equal end area friction sleeves, pore pressure <br /> corrections to sleeve friction, Fs, are not required <br />' The tip correction is Qt = Qc+ (1-a) .Ud <br /> where Qt is the corrected tip load <br /> Qc is the recorded tip load <br /> I Ud is the recorded dynamic pore pressure <br /> a Is the Net Area Ratio for the cone(typically 0 85 for ConeTec cones) <br /> Effective vertical overburden stresses are calculated based on a hydrostatic distribution of equilibrium <br /> pore pressures below the water table or from a user defined equilibrium pore pressure profile(this can be <br /> obtained from CPT dissipation tests) The stress calculations use unit weights assigned to the Soil <br /> Behaviour Type zones or from a user defined unit weight profile <br /> Details regarding the interpretation methods for all of the interpreted parameters is given in table 1 The <br /> appropriate references referred to in table 1 are listed in table 2 <br /> The estimated Soil Behaviour Type is based on the charts developed by Robertson and Campanella <br /> shown in figure 1 <br /> ITable 1 CPT Interpretation Methods <br /> Interpreted Description Equation Ref <br /> Parameter <br /> Depth mid layer depth <br /> AvgQt Averaged corrected tip(Qt) i - = <br /> AvgQt <br /> n - <br /> Av9Fs Averaged sleeve friction(Fs) i <br /> AvgFs=— Fs, <br /> n <br /> AvgRf Averaged friction ratio(Rf) • <br /> 100 Av9Fs <br /> AvgRf= °1° <br /> AvgQt <br /> AvgUd E Averaged dynamic pore pressure(Ud) 1 - -- Y <br /> AvgUd= Y—Ud, <br /> SBT Sod Behavior Type as defined by Robertson and Campanella 1 <br />