Abstract

In this study, the modified Severn-Trent constitutive model is used to simulate the mechanical behaviour of unreinforced, cemented, fibre, and fibre reinforced cemented Toyoura sand consolidated under drained and undrained triaxial compression and extension loading conditions. The model parameters are derived based on the experimental results in the current study, parametric study, trial and error, and by comparison with previous research studies. The comparisons covered ranges of material from 0–3% fibre, 0–3% cement, and 20–60% relative densities. The experimental results and model simulations were compared in terms of deviatoric stress versus axial strain, volumetric strain versus axial strain, and stress path behaviour. Two additional parameters ($M^{\mathrm{*}},\mathrm{ }{q}_0$) obtained from the laboratory tests are added to the standard Severn-Trent model to simulate the stress–strain behaviour of cement and fibre reinforced Toyoura sand. Calibration exercises based on studies in the literature and comparisons with the experimental studies herein are conducted with the modified version of the Severn-Trent model. A close agreement of model simulations with the experimental results is observed for many of the tests performed on pure Toyoura sand, cemented, fibre, and fibre reinforced cemented Toyoura sand. The modified model successfully captured the main features of the behaviour (e.g., increase in strength and stiffness with cement additive, increase in volumetric dilatancy due to fibre and cement additives, and general stress path behaviour for drained and undrained conditions) for different types of composite materials with reasonable accuracy. Hence, the current study might serve and should be considered as a step towards modelling of the behaviour of composite materials.

摘要

在这项研究中，修改后的 Severn-Trent 本构模型用于模拟在排水和不排水三轴压缩和拉伸加载条件下固结的未增强、胶结、纤维和纤维增强胶结 Toyoura 砂的力学行为。模型参数是根据当前研究、参数研究、试错法中的实验结果，并通过与以往研究的比较得出的。比较涵盖了 0-3% 纤维、0-3% 水泥和 20-60% 相对密度的材料范围。实验结果和模型模拟在偏应力与轴向应变、体积应变与轴向应变以及应力路径行为方面进行了比较。两个附加参数（${米}^{\mathrm{*}},\mathrm{ }{q}_0$) 从实验室测试中获得的结果被添加到标准 Severn-Trent 模型中，以模拟水泥和纤维增强 Toyoura 砂的应力-应变行为。基于文献研究的校准练习以及与本文实验研究的比较是使用 Severn-Trent 模型的修改版本进行的。在纯 Toyoura 砂、胶结、纤维和纤维增强胶结 Toyoura 砂上进行的许多测试中，观察到模型模拟与实验结果非常一致。修改后的模型成功地捕捉到了行为的主要特征（例如，水泥添加剂增加了强度和刚度，由于纤维和水泥添加剂增加了体积剪胀，以及排水和不排水条件下的一般应力路径行为）对于不同类型的复合材料具有合理的精度。因此，目前的研究可能并应被视为对复合材料行为建模的一步。