地震动力作用下纤维混凝土隧道衬砌的试验研究

通过与普通混凝土衬砌结构的对比,研究了纤维混凝土衬砌结构在地震动力作用下的反应和破坏形态.基于相似理论,采用5 m×5 m三向地震模拟振动台进行模型试验,通过输入不同大小的地震波,研究纤维混凝土衬砌在地震动力作用下的破坏特征,并探讨破坏机理.试验结果表明:素混凝土衬砌抗拉强度低、脆性大,裂缝基本呈直线型,断口干净整齐,裂缝挤压处有明显掉块痕迹;纤维混凝土具有限制裂缝发展和结构变形的能力;在地震动力作用下,纤维通过黏结应力能够使混凝土吸收更多能量,降低幅值,反应滞后,减轻了地震力对结构的破坏;纤维混凝土衬砌裂缝多呈锯齿形,挤压松散的小碎块通过纤维黏结在裂缝口.

Experimental Study on Fiber Reinforced Concrete Lining under Seismic Dynamic Action

In contrast to the normal concrete lining,the response and failure forms of fiber reinforced concrete lining under seismic dynamic action.Based on the similar theory,the model test has been carried out using the three-component shaking table with the size of 5 m×5 m by inputting earthquake wave with different magnitudes to study failure characteristics of fiber reinforced concrete lining and then discuss the failure mechanism.The results showed that the normal concrete lining had a low tensile strength and great brittleness,the shape of concrete cracks was linear,the crack fracture was clean and tidy,and the trace of concrete debris was clearly visible at the place of crack extrusion;fiber reinforced concrete had an advantage in controlling the development of crack and deformation of structure;under seismic dynamic action,the fiber could make concrete absorb more energy through the bond stress,so as to reduce the strain amplitude and delay response,which reduce the structural damage degree;most of the cracks of fiber reinforced concrete lining were of sawtooth shape,and the concrete debris was bonded in the crack opening through the fiber.