不同钢纤维类型混凝土动静态力学特性试验研究及应用

Experimental Study and Application of Dynamic and Static Mechanical Properties of Concrete with Different Steel Fibre Types

以云南某深部竖井钢纤维混凝土衬砌支护为背景,利用深部矿山现场使用的水泥、钢纤维及掘进工作面废矸石作为原材料,制作钢纤维混凝土试样,探究了不同钢纤维类型混凝土的动静态力学性能。通过单轴压缩、劈裂拉伸和动态压缩试验获得了钢纤维混凝土动静态力学性能及其破坏特征,结合高速摄像机和数字图像相关技术(DIC),探讨了钢纤维混凝土试样的裂纹演化规律。研究结果表明:双掺、三掺钢纤维混凝土的抗压强度均大于单掺钢纤维混凝土,三掺钢纤维在增强混凝土抗拉强度方面效果最佳,混凝土动态抗压强度随着掺杂钢纤维类型增加而增加;与素混凝土相比,钢纤维混凝土试样表面裂纹出现较晚;掺杂的钢纤维类型越多,试样峰值应变越大;素混凝土表现出脆性破坏特征,钢纤维混凝土则表现出延性破坏特征;将三掺钢纤维混凝土应用于矿山竖井衬砌支护,有效提高了竖井井壁的完整性和稳定性,为深部矿山工程安全高效开采提供了保障。

Based on the background of steel fiber concrete lining support for deep shafts in Yunnan Province.Cement,steel fibers,and waste gangues from the deep mine were utilized as raw materials to prepare steel fiber concrete samples.The dynamic and static mechanical properties of concrete with different steel fiber types have been investigated.The dynamic and static mechanical properties of steel fibre concrete and failure modes were obtained by uniaxial compression tests,Brazilian splitting tensile tests and dynamic compression tests.Furthermore,the crack evolution in steel fiber concrete was studied by using high-speed cameras and digital image correlation(DIC)method.The results show that the compressive strength of concrete mixed with three or double types of steel fibers is higher than that of concrete mixed with single types of steel fibers.The concrete mixed with three types of steel fibers is the most effective on increasing the tensile strength of the concrete.The dynamic compressive strength increases with the addition of steel fiber types.Surface cracks appeared later in steel fibre concrete specimens compared to plain concrete.The more types of steel fiber mixed,the higher the peak strain of the steel fiber concrete specimens.Plain concrete exhibits brittle failure characteristics,and steel fiber concrete shows ductile failure behavior.The concrete mixed with three types of steel fibers is used in mine shaft lining support,which effectively improves the integrity and stability of the shaft wall and provides a guarantee for the safety and high efficiency of the deep mining engineering.