Stress propagation in soil under vehicular traffic can be simulated either analytically based on the laws of continuum mechanics or numerically using finite element (FEM) and discrete element methods (DEM). Soil stress measured by a stress probe may differ from the "true" stress (i.e. the stress without the probe), as probes under- or over-estimate soil stress. No instrument has yet been developed to enable true stress measurement, while simulated stress can only be validated by comparing with measured stress. Hence, it is important to model the interaction of soil with a load cell probe to understand the difference between "with probe" and "without probe" soil stress. This study aimed at modelling the interaction of a load cell stress probe and soil under circular surface loading (i.e. by plate sinkage test) using FEM and DEM to understand the differences of the two methods, and to address whether arable soil is a continuum or a discrete media with regard to stress propagation. Simulated stress was compared with experimental stress (i.e. the stress measured by the probe). Experimental stress measurements were made in a clay loam soil at a gravimetric water content of 11% (corresponding to 0.5 PL, the lower plastic limit) and bulk densities of 1000 and 1150 kg m⁻³ corresponding to loose to slightly compacted soil, respectively. The load cell probe was installed at 0.15 m depth within a soil column, and varying surface loads were applied by a circular plate. The measured stress as a function of applied load was compared with simulated stress using either FEM or DEM. Simulations underestimated the measured stress, with an RMSE of 22.8 kPa for DEM and 40.1 kPa for FEM. The difference in soil stress between simulations with and without a probe were small for DEM, but significant for FEM. For FEM simulations, embedding a stress probe into the soil resulted in an overestimation of the “true” stress by 94% for the soil and boundary conditions tested. For DEM, the average overestimation was only 11%. Differences between FEM and DEM simulations with and without a probe were discussed and attributed to the sponge effect in FEM, and to differences in stress distribution at the soil-loading plate interface caused by the arching effect. Simulations showed that increasing the ratio of probe housing diameter to sensing surface decreased the stress overestimation for both DEM and FEM methods. More research is needed to address how stress propagation and the stress readings by a sensor probe are influenced in continuum and granular media, and how soil stress should be best modelled (as a continuum or granular material) depending on soil properties and characteristics.

车辆交通下土壤中的应力传播可以基于连续介质力学定律进行分析模拟，也可以使用有限元 (FEM) 和离散元方法 (DEM) 进行数值模拟。由应力探针测量的土壤应力可能不同于“真实”应力（即没有探针的应力），因为探针低估或高估了土壤应力。目前还没有开发出能够进行真实应力测量的仪器，而模拟应力只能通过与测量的应力进行比较来验证。因此，重要的是模拟土壤与称重传感器探头的相互作用，以了解“有探头”和“无探头”土壤应力之间的区别。本研究旨在模拟称重传感器应力探头和土壤在圆形表面载荷（即 通过板下沉测试）使用 FEM 和 DEM 来了解两种方法的差异，并解决耕地在应力传播方面是连续介质还是离散介质的问题。将模拟应力与实验应力（即探头测量的应力）进行比较。实验应力测量是在 11% 的重量含水量（对应于 0.5 PL，塑性下限）和 1000 和 1150 kg m 的堆积密度的粘土壤土中进行的^-3分别对应于松散到轻微压实的土壤。称重传感器探头安装在土柱内 0.15 m 深度处，并通过圆形板施加不同的表面载荷。将测量的应力作为施加载荷的函数与使用 FEM 或 DEM 的模拟应力进行比较。模拟低估了测量的应力，DEM 的 RMSE 为 22.8 kPa，FEM 的 RMSE 为 40.1 kPa。使用和不使用探针的模拟之间的土壤应力差异对于 DEM 而言很小，但对于 FEM 而言则显着。对于 FEM 模拟，将应力探头嵌入土壤中会导致对所测试的土壤和边界条件的“真实”应力高估 94%。对于 DEM，平均高估仅为 11%。讨论了使用和不使用探针的 FEM 和 DEM 模拟之间的差异，并将其归因于 FEM 中的海绵效应，以及拱形效应引起的土壤加载板界面处的应力分布差异。模拟表明，增加探头外壳直径与传感表面的比率可降低 DEM 和 FEM 方法的应力高估。需要更多的研究来解决应力传播和传感器探头的应力读数如何在连续介质和颗粒介质中受到影响，以及如何根据土壤特性和特性对土壤应力进行最佳建模（作为连续介质或颗粒材料）。模拟表明，增加探头外壳直径与传感表面的比率可降低 DEM 和 FEM 方法的应力高估。需要更多的研究来解决应力传播和传感器探头的应力读数如何在连续介质和颗粒介质中受到影响，以及如何根据土壤特性和特性对土壤应力进行最佳建模（作为连续介质或颗粒材料）。模拟表明，增加探头外壳直径与传感表面的比率可降低 DEM 和 FEM 方法的应力高估。需要更多的研究来解决应力传播和传感器探头的应力读数如何在连续介质和颗粒介质中受到影响，以及如何根据土壤特性和特性对土壤应力进行最佳建模（作为连续介质或颗粒材料）。