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CONETtC ConeTec <br /> —1-71 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 /> 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 /> Table 1 CPT Interpretation Methods <br /> Interpreted Description Equation Ret <br /> Parameter <br /> Depth mid layer depth <br /> AvgQt Averaged corrected tip(Qt) AvgQ1= Qt, <br /> n - -- <br /> E _ <br /> AvgFs Averaged sleeve friction(Fs) I _ <br /> AvgFs=-1 RFs, <br /> n <br /> AvgRf Averaged faction ratio(Rf) AvgFs <br /> AvgRf=100%• <br /> Avgo <br /> AvgUd Averaged dynamic pore pressure(Ud) 1 <br /> Avg Ud=-�fid, <br /> SBT Sal Behavior Type as defined by Robertson and Campanella 1— <br />