Modelling of fibre-cohesive soil mixtures
Modelling of fibre-cohesive soil mixtures
复制标题
DOI：
10.1007/s11440-013-0283-y
复制
发表时间：
2014-12-01
期刊：
影响因子：
5.7
通讯作者：
Ibraim, E.
中科院分区：
文献类型：
--
作者：
Diambra, A.;Ibraim, E.
提出了一种新的纤维增强粘性土本构模型。该模型将类 Cam-Clay 边界表面模型与弹塑性一维纤维单元模型相结合。采用可以考虑纤维取向的任何空间分布的“涂抹程序”，将纤维中产生的离散拉力转换为复合材料的应力。纤维应力的贡献受到拉拔机制引起的土壤-纤维粘合退化和纤维拉伸强度的限制。还考虑了纤维断裂的最终发生。分析了固结和剪切加载模式的模型性能，并与文献中可用的实验数据进行了定性比较。对于固结加载，不产生拉应力因此，对于排水剪切荷载，添加纤维可以导致剪切强度的持续增加，这似乎是由两个参数控制的：纤维拉伸刚度和纤维/土壤应变比，这两个参数解释了纤维/土壤基质界面上任何可能的滑移或剪切变形，对于不排水剪切荷载，纤维的增强效果似乎被孔隙水压力的增加所抵消。与已发表的实验数据一致，该模型还表明含水量是控制纤维不排水剪切有效性的关键因素。最后，提供了模型预测的纤维增强粘性土临界状态的分析。
A new constitutive model for fibre-reinforced cohesive soil is proposed. The model combines a Cam-Clay like bounding surface model with an elastic-plastic one-dimensional fibrous element model. A "smearing procedure'', which can consider any spatial distribution of fibre orientation, is employed to transform discrete tensile forces developed in the fibres into stresses for the composite material. The fibre stress contribution is bounded by both degradation of soil-fibre bonding due to pull-out mechanism and tensile strength of the fibres. Eventual occurrence of fibre breakage is also considered. The model performances are analysed for both consolidation and shearing loading modes, and qualitative comparison is performed with experimental data available in the literature. For consolidation loading, tensile stresses are not developed in the fibres and thus the fibre effect is rather limited. For drained shear loading, addition of fibres can result in a consistent shear strength increase. The beneficial effect of fibres seems to be controlled by two parameters: the fibre tensile stiffness and the fibre/soil strain ratio that accounts for any possible slippage or shear deformation at the fibre/soil matrix interface. For undrained shear loading, the strengthening effect of the fibres appears to be counteracted by the increase in pore water pressure, induced by the additional confining contribution of the fibres. In agreement with published experimental data, the model suggests also that the moisture content is a key factor governing fibre effectiveness for undrained shearing. Finally, analysis of the model predicted critical states for fibre-reinforced cohesive soil is provided.