加筋粗粒土大型三轴试验研究

Large-scale Triaxial Test of Reinforced Coarse-grained Soils

采用大型三轴剪切仪,对粗粒土、加筋粗粒土强度变形特性进行了试验研究。试验结果表明:不同围压条件下粗粒土和加筋粗粒土剪切的应力-应变关系类似,应力应变关系表现为应变硬化型;当轴向应变较小时,加筋效果不明显,随着轴向应变的逐渐增大,加筋效果逐渐发挥;粗粒土加筋后的内聚力c有明显增加,但是内摩擦角φ基本不变,侧向变形减小,体积变形增大;对邓肯-张模型的适用性进行分析,表明邓肯-张模型中切线弹性模量能很好适用于加筋粗粒土,但不能很好地反映加筋粗粒土变形特性。在试验的基础上提出了轴向应变与侧向应变的二次函数关系,建立了粗粒土的体积应变与轴向应变的函数方程,并对粗粒土以及加筋粗粒土的三轴试验体积应变数据进行了预测。

The Strength and deformation characteristics of coarse-grained soils and reinforced coarse-grained soils were studied based on large-scale triaxial shearing tests. Experimental results showed that the stress-strain relationships of coarse-grained soils and reinforced coarse-grained soils are similar under different confining pressures, both showing strain hardening, Reinforcement effect is not obvious when the axial Strain is small, and the reinforcement effect gradually starts to work with the increment of axial strain. Reinforced coarse- grained soil has a larger cohesion c, while the inner friction angel ~ nearly keeps changeless. And it＇ s axial strain decreases, volumetric strain increases. Applicability analysis of Duncan-chang model showed that Duncan-Chang model can reflect the tangent elastic moduli of reinforced coarse-grained soils, but can＇ t reflect its deformation well. A function was put forward to fit axial strain and lateral strain, and a volumetric strain function was established for coarse-grained soils and reinforced coarse-grained soils, and then the volumetric strain of the soil-sample was predicted.