Abstract In order to alleviate the adverse effect of water pressure in the drainage and storage shield tunnel, it is proposed to add synthetic macro-fiber into the tunnel segment considering that the internal medium of the tunnel is rainwater and sewage. Through material mechanical properties and straight beam loading tests, the application effect of synthetic macro-fiber in drainage and storage tunnel segments is studied. The results show that, compared with the mechanical parameters of plain concrete, the compressive strength, flexural strength and elastic modulus of fiber reinforced concrete are reduced by 1.8%, 7% and 4% respectively, and the addition of fiber will reduce the mechanical properties of concrete. After the concrete cracks, the reinforcement stress of PPF1 (synthetic macro-fiber 1),PPF2 (synthetic macro-fiber 2) and SF (steel fiber) specimens decreases by 2%, 10% and 17% respectively compared with that of ordinary concrete. The fiber shares part of the tensile stress of the reinforcement, reflecting the advantages of fiber reinforced concrete. From the distribution pattern, the cracks of ordinary reinforced concrete are"sparse and wide", and the maximum crack width at the end of the test is 0.55 mm; the cracks of synthetic fiber reinforced concrete are "dense and narrow", and the maximum crack width at the end of the test is 0.3 mm. After the concrete cracks, the fiber reduces the width of the crack, and the addition of fiber is beneficial to the crack control of the tunnel lining structure.
Abstract：
In order to alleviate the adverse effect of water pressure in the drainage and storage shield tunnel, it is proposed to add synthetic macro-fiber into the tunnel segment considering that the internal medium of the tunnel is rainwater and sewage. Through material mechanical properties and straight beam loading tests, the application effect of synthetic macro-fiber in drainage and storage tunnel segments is studied. The results show that, compared with the mechanical parameters of plain concrete, the compressive strength, flexural strength and elastic modulus of fiber reinforced concrete are reduced by 1.8%, 7% and 4% respectively, and the addition of fiber will reduce the mechanical properties of concrete. After the concrete cracks, the reinforcement stress of PPF1 (synthetic macro-fiber 1),PPF2 (synthetic macro-fiber 2) and SF (steel fiber) specimens decreases by 2%, 10% and 17% respectively compared with that of ordinary concrete. The fiber shares part of the tensile stress of the reinforcement, reflecting the advantages of fiber reinforced concrete. From the distribution pattern, the cracks of ordinary reinforced concrete are"sparse and wide", and the maximum crack width at the end of the test is 0.55 mm; the cracks of synthetic fiber reinforced concrete are "dense and narrow", and the maximum crack width at the end of the test is 0.3 mm. After the concrete cracks, the fiber reduces the width of the crack, and the addition of fiber is beneficial to the crack control of the tunnel lining structure.
GUAN Linxing1 WEN Zhuyin1 WANG Xiaopeng2 YOU Guangming1 SUN Wei1 ZHUANG Qianwei3
.Test and Study on the Application of Synthetic Macro-fibers in the Segements of Drainage and Storage Tunnels Built by Shield Method[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(6): 258-265
2022, Vol. 59 