玄武岩纤维筋的力学特性与破坏模式试验研究

玄武岩纤维筋预应力锚索的主体受力构件为BFRP筋,对BFRP筋的力学性质和破坏模式进行研究,可为BFRP筋预应力锚索在不同岩土工程对象中的应用提供参考和技术指导。研究表明:BFRP筋是一种典型的线弹性材料,极限荷载张拉破坏前筋材只存在线性应变,张拉过程中由于纵向拉伸下筋材环氧树脂基体传递剪力滞后使得BFRP筋具有自断口向两端发展的“灯笼状”破坏模式,极限荷载作用下BFRP筋聚集的弹性能瞬间释放,筋材发生脆性破坏,破坏前无明显征兆；相比于表面未粘砂的BFRP筋,表面粘砂的BFRP筋由于砂粒占据了筋材表面一定空间,导致其环氧树脂基体对玄武岩纤维的包裹程度降低,造成表面粘砂的BFRP筋强度稍低于表面未粘砂的BFRP筋。总的来看,尽管BFRP筋的抗拉强度较高,但其变形能力和抗剪切能力较弱,破坏前不存在屈服变形,单一手段的BFRP筋预应力锚索在动载或大变形能力的岩土锚固工程中适用性较差。

Experimental study on the mechanical property and failure mode of the BFRP tendon

For basalt fiber reinforced polymer(BFRP) prestressed anchor cable,the BFRP tendon is the main stress component. Study on its mechanical property and failure mode of the BFRP tendon can provide help for the application of BFRP prestressed anchor cable in the geotechnical engineering fields. The results show that the BFRP tendon is a typical linear elastic material. There is only linear strain before the tensile failure of the BFRP tendon at the ultimate load. During the process of tensioning, due to the shear stress lagging for the epoxy resin matrix of the BFRP tendon, the BFRP tendon presents a characteristic of bursting failure mode at the condition of applied ultimate load, when the failure develops from the middle location to the end location of the BFRP tendon. Compared with the BFRP tendon without sand coated, sand particles for the BFRP tendon with sand coated occupy a certain space of the epoxy resin matrix, which results in the strength of the BFRP tendon withsand coated slightly lower than that of BFRP tendon without sand coated. Although the tensile strength of BFRP tendon is high, its strain and shear resistance are weak. There is no yield deformation for the BFRP tendon as it is broken at the condition of applied ultimate. The elastic energy in the BFRP tendon releases instantly. Thus, the BFRP prestressed anchor cable may has apoor applicability in those geotechnical anchorage engineering with dynamic load or large deformation.