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1 CONETEC <br /> QmHeTec <br /> Geotechnical and Environmental Site Investigation Contractors <br /> ConeTec CPT Interpretations as of January 7, 1999 (Release 1.00 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) o Ud <br />' where Qt is the corrected tip load <br /> Qc is the recorded tip load <br /> 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 distnbution 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 />' Table 1 CPT Interpretation Methods <br /> Interpreted Descnpbon Equation Ref <br /> 1 Parameter <br /> Depth mid layer depth <br /> AvgQt Averaged corrected tip(Qt) /4v t <br /> gQ = 1 E Qt, <br /> AvgFs Averaged sleeve friction(Fs) AvgFs=1 21 Fs <br /> n -1 <br /> - <br /> AvgRf I Averaged friction ratio(Rf)1 AvgFs AtigRf-100%0 <br /> AvgQt <br /> AvgUd Averaged dynamic pore pressure(Ud) t i <br /> AvgUd Ud, <br /> In <br /> SBT Soil Behavior Type as defined by Robertson and Campanella � <br />