Safety Analysis Method for Steel Fiber Sprayed Concrete Structures

As a new type of material for tunnel shotcrete support, steel fiber shotcrete has better tensile, crack resistance, and durability. To study its impact on bearing capacity and cracking when used for tunnel support, a safety analysis method for steel fiber shotcrete structures was established. This analysis method detects whether the steel fiber sprayed concrete component cracks under load based on the size of the steel fiber sprayed concrete component. If it does not crack, the component size is reasonable; If cracking occurs, it is necessary to calculate the actual crack width to determine whether it meets the requirements of safety regulations. According to the analysis process, engineering verification was conducted on three types of support types of steel fiber shotcrete for Class Ⅲ surrounding rock, namely Type Ⅰ, Type Ⅱ, and Class Ⅳ surrounding rock. The results showed that the thicker the steel fiber shotcrete for the same level of surrounding rock, the less likely it is to crack, and the higher its safety. The greater the load on different levels of the surrounding rock, the easier it is for steel fiber sprayed concrete of the same thickness to crack and the wider the crack width after cracking. At the same time, the theoretical calculation results are basically consistent with the on-site test results, verifying the practicality and effectiveness of the safety analysis method for steel fiber-sprayed concrete structures.