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采用常三轴动力试验仪对不同钢纤维含量、不同围压、应变速率为10-3/s作用下混凝土的主要参数进行试验与分析,结果表明:①随着围压的增大,各种不同钢纤维含量的混凝土峰值应力显著提高;②同一种围压条件下,基体强度等级愈高峰值应力的增加幅度也愈高,峰值应力随钢纤维含量的变化不大;③围压对峰值应变的影响较大,随围压的增大,峰值应变明显增大;在有围压的条件下峰值应变随钢纤维含量的增加而提高得不多;④钢纤维含量对割线模量有一定的影响,对基体强度较低的混凝土的影响要比强度等级高的混凝土显著;围压对钢纤维混凝土割线模量也有一定影响,随围压的增加,钢纤维混凝土的割线模量表现为先增加后减小,但增加和减小的程度都不大;围压的变化对基体强度较高的混凝土割线模量影响不大,对基体强度较低的混凝土基本呈下降趋势;⑤混凝土的泊松比离散性较大,钢纤维含量和围压对泊松比的影响不是很大,主要集中在0.11～0.20之间;⑥在三轴动荷载的情况下,钢纤维的掺入对混凝土的压缩韧度指数ηc5基本上没有影响;但韧度指数ηc10随钢纤维含量的增加有显著提高,变形不大时作用不明显,当变形较大时,钢纤维提高韧性的作用得以充分体现;钢纤维的增韧效果在基体强度较低的混凝土中表现得较为显著。
The main parameters of concrete with different steel fiber content, different confining pressure and strain rate of 10-3 / s were tested and analyzed by the usual three-axis dynamometer. The results showed that: (1) With the increase of confining pressure, The peak stress of concrete with different steel fiber content increased significantly; (2) Under the same confining pressure, the peak stress increased with the increase of the matrix strength, and the peak stress did not change much with the steel fiber content. (3) , The peak strain increases obviously with the increase of confining pressure; the peak strain increases little with the increase of steel fiber content under confining pressure; (4) The content of steel fiber has a certain effect on the secant modulus , The effect of concrete with lower matrix strength is more significant than concrete with higher strength grade. The confining pressure also has some influence on the secant modulus of steel fiber reinforced concrete. With the increase of confining pressure, the secant modulus of steel fiber reinforced concrete For the first increase and then decrease, but the degree of increase and decrease are not large; the confining pressure changes have little effect on the secant modulus of the concrete with higher matrix strength, and the basic strength of the concrete with lower matrix strength basically declines; ⑤ Concrete Poisson’s ratio is larger, the influence of steel fiber content and confining pressure on Poisson’s ratio is not large, mainly concentrated in the range of 0.11 ~ 0.20; ⑥ In the case of triaxial dynamic load, The compressive toughness index ηc5 of concrete has almost no effect; but the toughness index ηc10 increases significantly with the increase of steel fiber content, the role of deformation is not obvious, when the deformation is large, the role of steel fiber to improve the toughness can be fully reflected The toughening effect of steel fiber is more obvious in concrete with lower matrix strength.