Analytically and experimentally based resistance factors for "full-flow" penetrometers

There are several geotechnical problems for which the formulation of large deformations is vital for their solution. Among these problems are in-situ penetration tests. In this paper, a new numerical approach is used to solve such problems efficiently with the aim to calibrate fundamental soil properties to fit the global penetration resistance obtained from experimental studies. The utilized numerical method treats the continuum as rigid plastic with a non-uniform strength field, where the spatial distribution of strength is determined by converting time changes into spatial distributions using the governing equation of steady state flow. For this purpose, the method employs an upstream weighting technique for determination of information flow within the domain. Using the suggested method, the resistance factors for in-situ T-bar and ball penetrometers were obtained under a various soil conditions. These included the rate effect on the soil, strain softening and anisotropy, all of which affect the shear strength of the soil. General expressions for the resistance factors of the T-bar and ball penetrometers are finally suggested for engineering use.