Abstract
Adding fiber can improve the brittleness of plain concrete. Compared with plain concrete, basalt fiber-reinforced concrete has the advantages of strengthening, toughening, and crack resistance. Compared with steel fiber-reinforced concrete, basalt fiber-reinforced concrete has better construction performance. Basalt fiber concrete is a type of inorganic material with environmental protection and high mechanical properties, which has an important mechanical advantage for controlling the deformation of the soft surrounding rock tunnel. Through the indoor model test of mechanical behavior of reinforced concrete and basalt fiber-reinforced concrete lining, the bearing characteristics of basalt fiber-reinforced concrete lining was studied. The results show that, compared with reinforced concrete, the initial crack load of basalt fiber-reinforced concrete is increased by 20%; the toughness of lining structure is enhanced by adding basalt fiber, and the lining can still bear large bending moment and deformation after the initial crack appears; after the initial crack appears, the bearing characteristic curve of reinforced concrete lining rises slowly and converges rapidly; the bearing characteristic curve of basalt fiber-reinforced concrete lining rises slowly, and there is no sign of convergence when it reaches 2 times of initial crack load. For the soft surrounding rock tunnel, it is necessary to seal the rock surface as early as possible, provide support as soon as possible, and have a certain deformation capacity. Basalt fiber-reinforced concrete can better meet these needs.
Highlights
With the rapid development of China’s infrastructure, traffic tunnels in high altitude, high latitude, and high seismic intensity areas are emerging, and the geological conditions in the tunnel site are complex and changeable, which put forward higher requirements for the mechanical properties of the tunnel support
Plain concrete is a kind of brittle material with low tensile strength [5,6,7], which makes it unable to play the role of supporting material in the soft surrounding rock tunnel that needs to have certain deformation capacity. erefore, adding fiber into plain concrete is deemed to be a reasonable solution to this problem. e use of fiber can reduce the costs of tunnel construction and save the cost of construction time
Based on the Dujiashan Tunnel of Guangzhou Gansu Expressway, this paper studies the mechanical behavior of basalt fiber-reinforced concrete support structure under the condition of soft surrounding rock, which is of great significance for the study of deformation control technology of soft surrounding rock tunnel and mechanical properties of basalt fiber-reinforced concrete lining
Summary
With the rapid development of China’s infrastructure, traffic tunnels in high altitude, high latitude, and high seismic intensity areas are emerging, and the geological conditions in the tunnel site are complex and changeable, which put forward higher requirements for the mechanical properties of the tunnel support. Adding fiber into plain concrete can enhance the toughness and crack resistance of concrete [8], which is just as well suited to the performance requirements of soft rock tunnel support materials. Basalt fiber is an environmentally friendly and high-performance inorganic material, which can effectively improve the compressive strength of concrete (the maximum increase is about 17%) [19] and early strength [20], improve the brittle failure characteristics of concrete and improve the crack resistance [21], and improve the splitting strength (up to 27%) and flexural strength (up to 25%) [22]. Erefore, basalt fiber-reinforced concrete support structure has a great mechanical advantage for controlling the deformation of the soft surrounding rock tunnel. Based on the Dujiashan Tunnel (sericite phyllite) of Guangzhou Gansu Expressway, this paper studies the mechanical behavior of basalt fiber-reinforced concrete support structure under the condition of soft surrounding rock, which is of great significance for the study of deformation control technology of soft surrounding rock tunnel and mechanical properties of basalt fiber-reinforced concrete lining
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