Abstract
The theory of a moving point dislocation is applied to the rational determination of permeability and consolidation coefficients from piezocone-sounding data. Motion of the process zone in following the penetrometer tip is shown to result in important differences in behavior between static and undrained analogs to penetration. A distinction is drawn between pressure buildup and postarrest dissipation behaviors recorded both at the tip and along the shaft. Tip pressures are shown to become steady within approximately 1 s following drivage initiation at a standard rate of 2 cm/s. Shaft pressures within 10 radii of the tip equilibrate within 10 s. Postarrest pressure dissipation at the tip enables consolidation coefficient, c, to be determined independently. Nonuniqueness in pressure-dissipation response along the shaft is shown to preclude independent determination of consolidation behavior for consolidation coefficients less than about 20 cm2/s, under standard penetration. Hydraulic conductivities, k, are directly evaluated from induced pore pressure magnitudes recorded either at the tip or along the shaft, given a priori knowledge of consolidation coefficient, c. Piezocone-derived magnitudes of consolidation coefficient enable conductivities to be determined independently of laboratory or material-specific empirical determinations. Relationships are developed for net cone end bearing (qn) as a linear function of elastic parameters and for pore pressure ratio (Bq). Pore pressure ratio is shown to be an insensitive index in low c soils. Results from well-documented field investigations in both normally consolidated and overconsolidated materials are used to independently establish the applicability of the proposed parameter determination techniques. Satisfactory correspondence is obtained.
Original language | English (US) |
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Pages (from-to) | 1601-1623 |
Number of pages | 23 |
Journal | Journal of Geotechnical Engineering |
Volume | 119 |
Issue number | 10 |
DOIs | |
State | Published - Jul 1993 |
All Science Journal Classification (ASJC) codes
- General Environmental Science
- General Earth and Planetary Sciences