## Abstract

Limits are defined for the transition from partially drained to undrained penetration during uCPT testing. These limits prescribe the range of cone metrics for which coefficient of permeability magnitudes may be recovered from peak pore pressure data, on the fly. The transition from partially drained to undrained behaviour is defined through the traditional non-dimensional metrics of cone resistance Q_{t}, sleeve friction F_{r} and pore pressure ratio B_{q}, together with the undrained shear strength S _{u}, normalised by shear modulus G and in situ effective stress, σ′_{v0}. For plausible ranges of S_{u}/ σ′_{v0} and G/ S_{u}, the lower bound for transition from partial drainage is defined by the uCPT metric products and ratios of B_{q}Q_{t} = 1-2, Q_{t}F_{r} = 0-3, and B _{q}/F_{r} = 4, with the first and last proving the best determinants of drainage condition. Standard (2cm/s and 10 cm^{2} face area) uCPT data together with independently measured permeabilities identify the transition from partially drained to undrained conditions at permeability magnitudes of the order of 10^{-5} m/s. These results are used to define limits of partial drainage where peak tip pore pressures may be used to recover in situ permeability profiles. For conditions of partial drainage, a non-dimensional permeability K_{D} is defined independently in terms of cone metrics as K_{D} = 1/B_{q}Q_{t} (with B _{q}Q_{t} < 1.2), enabling permeability to be recovered during standard penetration for K > 10^{-5} m/s. Where undrained data are excluded, non-dimensional permeability K_{D} is optimally defined as K_{D}, = 0-62/(B_{q}Q_{t})^{1.6}.

Original language | English (US) |
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Pages (from-to) | 679-685 |

Number of pages | 7 |

Journal | Geotechnique |

Volume | 57 |

Issue number | 8 |

DOIs | |

State | Published - Oct 2007 |

## All Science Journal Classification (ASJC) codes

- Geotechnical Engineering and Engineering Geology
- Earth and Planetary Sciences (miscellaneous)