棕麻纤维加筋砂的三轴试验研究

Study on Flax Fiber-reinforced Sand by Triaxial Test

利用室内三轴试验研究棕麻纤维加筋土的应力-应变关系特性以及强度特征,探讨不同棕麻纤维含量和不同围压下棕麻纤维加筋土主应力差以及抗剪强度指标的变化规律,分析筋材在土体剪切过程中的阻抗机理.试验结果表明:棕麻纤维加筋土的强度和抗变形能力较纯砂的有显著增强;与纯砂相比,棕麻纤维加筋土的抗剪强度指标有所变化,内摩擦角和黏聚力均增加,但内摩擦角增加幅度较小,黏聚力增幅较大;在试样含水率和纤维长度一定的情况下,棕麻纤维加筋土的主应力差、抗剪强度以及抗剪强度指标随着棕麻纤维百分含量的增加呈现先增加后减小的变化趋势,且存在最佳棕麻纤维含量值.

Traxial test were carried out to research the stress-strain relationship and strength property of flax fiber-reinforced sand.The variation of shear strength indexes of flax fiber-reinforced sand in different flax fiber content and different confining pressure was investigated.And the frictional mechanism between the flax fiber and sand in the shearing process was studied.The laboratory test results showed that,the strength and the capacity for resisting the deformation of flax fiber-reinforced sand were better than those of pure sand.Compared with the pure sand,the shear strength indexes of flax fiber-reinforced sand were changed,the cohesive and friction angle were increased,while the friction angle increased relatively less,the cohesive force increased greatly;in the certain number of rate of water and fiber length,the value of deviator stress,shear strength and cohesion firstly increased and then decreased with the increase of flax fiber content,and there existed an optimum fiber content.