高水充填材料失稳破坏特征研究及性能改善

针对高水充填材料强度低、稳定性差等问题,对高水充填材料的性能进行改善,并通过应力-应变和蠕变试验,研究高水充填材料失稳破坏特征;通过扫描电镜与差热-热重实验,研究高水充填材料的微观结构与高水充填材料的改善机理。结果表明:高水充填材料在应力水平较小时,蠕变曲线有衰减蠕变和稳定蠕变2个阶段;当应力水平达到临界荷载时,蠕变曲线出现加速蠕变阶段;应力-应变关系曲线宏观上有4个阶段:初始变形阶段,弹性阶段,塑性变形阶段和破坏阶段;改善后的高水充填材料胶凝时间缩短,抗压强度提高,弹性模量增大,失稳破坏的临界荷载提高,变形减小;改善后的高水充填材料生成更多的钙矾石晶体和铝胶,硬化体微观结构更致密,有利于提高充填体的承载能力。

Unstable failure characteristics and performance improvement of water-high filling materials

For the low strength and poor stability of water-high filling materials improves the property of it.The unstable failure characteristics of water-high filling materials was studied by stress-strain and creep test.The microstructure of water-high filling materials and the improvement mechanism of it were analyzed by using scanning electron microscopy (SEM) and different thermal analysis-thermal gravimetry (DTA-TG).It is found that the creep curve has decelerating and stable stage when stress level is low and it increase accelerating stage when stress level reach critical load.The stress-strain curve has initial deformation,elastic,plastic deformation and disruption four stages.The gel time shortened,compressive strength improved,elastic modulus increased,unstable failure critical load raised and deformation decreased of water-high filling materials after improvement.Owing to more ettringite crystals and alumina gel in the water-high filling materials after improvement,the microstructure of hardening body become more densification and bearing capacity improved.