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Horizontal penetrometers have been recently examined as instruments for on-the-go mapping of soil strength/compaction. Since the horizontal penetrometer resistance (PR) provides a composite soil strength parameter, it needs to be characterized with respect to variations in soil physical properties as well as standardized with respect to the operational parameters of the device. In a recent study, a 3D finite element (FE) model was developed for a single-tip horizontal penetrometer–soil interaction (cf. Part I of this study; Naderi-Boldaji et al., 2013b ) and the effect of some soil/operational parameters (mechanical properties of soil, model boundary effects, penetrometer tip extension, working depth and soil failure mode ahead of the tine) on PR was investigated. In the second part of this study, two soil bin tests were conducted to evaluate the PR predictability of the FE model. This is a crucial step for finite element modelling of soil compaction reflected by PR as affected by soil water content, bulk density and texture. The soil bin tests were carried out in a clay loam soil at two different water contents of 0.171 and 0.183 g g−1 and dry bulk densities of 1.64 and 1.59 Mg m−3, respectively, to evaluate the model at two different levels of PR. The soil elastic parameters (i.e. Young's modulus of elasticity and Poisson's ratio) were estimated from oedometer (uniaxial compression) tests on confined and unconfined undisturbed samples taken within the working depth of the penetrometer whilst the plastic parameters (the parameters of the Drucker–Prager constitutive model) were determined by triaxial tests at three levels of confining stress. The results indicated the practical and efficient use of oedometer tests for estimating soil elastic parameters for numerical simulations. The FE model predicted the measured PR with a small error (

A fundamental step to employing a horizontal penetrometer for on-the-go measurement of soil compaction is to characterize the horizontal penetrometer resistance (PR) as affected by soil mechanical/physical properties and design/operational parameters of the penetrometer. Such complicated soil–tool interactions are preferably investigated using numerical analyses, e.g. finite element (FE) method. A symmetric 3D FE model for a single-tip horizontal penetrometer–soil interaction was developed and evaluated in ABAQUS/Explicit. In the first paper of this study, we focus on the development of the model and the evaluation of some affecting parameters, namely (i) boundary effects, (ii) element size (mesh density) around the conical tip of the penetrometer, (iii) sensitivity of the predicted PR with respect to (a) soil mechanical properties (b) tip extension (i.e. the distance between cone base and shin of the carrying tine), (c) working depth, and (iv) soil layering and the effect of working depth in relation to the tine critical depth. The elastic–plastic parameters of the soil constitutive model (Drucker–Prager) were determined from samples taken within the working depth of the penetrometer in a soil bin. The results showed that for the tested penetrometer dimensions and the given soil specifications (i) the simulated soil box should be at least 0.8 m long and 0.4 m wide to avoid interference from the boundaries on predicted PR; (ii) the element size around the cone should be fine enough (9 mm) for a stable steady-state simulated PR; and (iii) the tip extension must be >4 cm to avoid the effect of tine on PR. PR was found to be most sensitive to soil internal angle of friction and compressive yield stress, whilst Poisson's ratio had no significant effect, and Young's modulus of elasticity and soil-metal coefficient of friction showed only minor impacts on PR. Due to soil surcharge, PR increased by 30% when increasing the working depth of the penetrometer from 5 to 40 cm in a homogenous soil profile. An effective radius of 6 cm was found for the soil failure around the cone. The simulations showed that when the cone was located above the tine critical depth (i.e. inside the crescent failure zone), the PR was lower and the PR signal was unstable compared with when the cone worked out of crescent failure zone at the same depth. The model developed here can be used to characterize PR with respect to the state of soil strength/compaction across soil types.