Finite radius penetrometers

Relations may be developed to represent the steady pore fluid pressures that develop around a penetrometer under steady penetration, at penetration rate, U. These rtKxlels necessarily employ simple linearized constitutive relations, but incorporate the important influence of a porous medium migrating past the penetrometer tip, albeit in a simplified form. Dislocation models (Elsworth, 1991 1993) may be applied to represent a penetrometer of infinitesimal-radius, but suffer the disadvantage that penetration-induced pressures become singular at the assumed penetrometer tip. The approximate solution for a finite radius penetrometer avoids this shortcoming, as explored in the following. 

This defines a relation between B -Q, that is plotted in Figure 3(a) for a variety of magnitudes of the non-dimensional parameter, Kd, directly proportional to permeability. This is similar to Figure 2, but is representative of a finite-radius penetrometer tip, where dilation or compaction of the tip process zone is accommodated. 

Figure 3 Contoured plots of (a) B Q,. (b) Fr-Q and (c) B -Fr contoured for Kd for a penetrometer of finite radius. Values ofK are shown forA=I and O, 0=100 kPa. The empirical results of Olsen (1994) are shown dashed in Figure (b).

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