Experimental Study on Load Bearing Characteristics of Steel Fiber Reinforced Concrete Lining in the Soft Surrounding Rock Tunnel

Abstract

Tunnels in soft rock with high ground stress will encounter the problem of large deformation of surrounding rock. The study of new high-performance tunnel lining materials is of great significance to improve the safety of tunnel excavation in soft rock with high ground stress. In this paper, the bearing characteristics of the plain concrete, the reinforced concrete, and the steel fiber reinforced concrete lining are studied by the indoor model experiment. By extracting the displacement and stress data of typical parts of lining, the bearing characteristics of the steel fiber reinforced concrete lining are analyzed and summarized. The test results show that the initial crack load and ultimate load of the steel fiber reinforced concrete lining are significantly higher than those of the other two materials, and the crack development path is more tortuous, and the number of cracks is greater. Steel fiber can improve the bearing capacity and deformation capacity of the lining structure so that the failure mode of the lining structure changes from brittle shear failure to ductile bending failure. It is concluded that steel fiber reinforced concrete can improve the toughness of lining. Because of its excellent mechanical properties, steel fiber reinforced concrete can completely replace the conventional reinforced concrete as a new lining material for soft rock tunnel. The above research results are of great significance to the design and construction of tunnel lining in the soft surrounding rock.

Image Recognition about Stability of Soft Surrounding Rock in Tunnel Based on ILBP Algorithm

“…e quality of the latter directly affects the detection results, and it is likely to be affected by external factors such as uneven illumination and distortion of line-array camera shooting [2]. erefore, for these two methods, the accuracy of detection completely depends on the professional level and quality of technical personnel, and the measurement results of different personnel are not the same.…”

Cracking Pattern and Bearing Capacity of Steel Fiber-Reinforced Concrete Single-Layer Tunnel Lining

“…The comparison between the physical and similar materials of surrounding rock and the physical and mechanical parameters of the class IV surrounding rock [43] is shown in Table 9. Based on the successful test experience of existing research [49,50], the steel fiber was simulated using experimental ultra-fine steel fiber to carry out the relevant model test, as shown in Figure 7. The content of steel fiber was determined according to the recommended content for steel fiber identified in the second chapter.…”

Experimental Study of a New Concrete Admixture and Its Function in Filling and Reinforcing Granite Fissures

“…High-performance concrete materials have been studied, but there are still a limited number of studies on the use of these materials in the lining supports of the surrounding rocks in underground engineering projects. Through laboratory model tests, Cui et al [13] found that after becoming deformed, the initial support of steel-fiber concrete may intersect with the characteristic curve of the surrounding rock, thereby enabling the surrounding rock structure to remain stable. Guo [14] studied the concrete used for grouting reinforcement, compared the setting times of phosphoric acid-water glass and cement-water glass with different mix ratios, and proposed relevant design parameters.…”