The Study On Steel Fiber's Effect Of Crack Resistance And It's Application In Shield Segment

In the concrete, doping appropriate high modulus of steel fiber, alter its brittleness, effectively control the crack production and growth, playing role in the strength and toughness improvement, effective to overcome its inherent defect such as the low tensile strength of concrete, easy to crack, the fatigue resistant badly. SFRC superiority of the extensive cognitive, it makes rapid application development, along with the more in-depth study.Under the existing 'Design criterion of concrete structure', the crack width does not reflect the role of steel fiber. Therefore, 'Technical specification for fiberReinforced Concrete Structures' introducesβ_cw to reflect the resistance of steel fiber effect when calculating the crack width, but in the 'Technical specification forfiber Reinforced Concrete Structures' only given theβ_cw below the FC45, precast segment's capacity requirements and waterproof require it has high strength and high-permeability, so reinforced concrete pipe unit is the main C50 or more of the high-strength concrete. So take this as the starting point of Experimental studies and theoretical analysis to quantify steel fiber crack width and coefficient of the film design applications.Based on the theory average crack width formula, and with steel fiber crack width formula Steel fiber derived crack width coefficient formula. In the formula we can learn cross-section size, tensile strength of concrete and the moment coefficient of a certain influenceThrough testing of bias short columns and pure bending beams, statistical analysis test results is 0.46 and 0.45. In order to make test results more universal, the numerical test, change parameters, such as the cross section of length, width, obtained under various conditions crack width, and moment with the coefficients affect relations. Further analysis of steel fiber crack width coefficient of variationAccording to the actual segment of the design load for Steel Fiber Reinforced Concrete segment design, 8Φ14 meet the requirements. And then for entity model test, analysis of the course of the test characteristics of the cracks, the former has been slightly higher than the latter, thus show that the coefficient of practicality and reliability.Finally, use the Numerical test. From another perspective verify its reliability.The research results of similar works have a certain reference. By the trial confirmed C50 SFRC coefficient and its impact on the analysis fill the 'Fiber Reinforced Concrete Structures of order' gaps.