全尾砂胶结充填体的爆破振动破坏机制和振动速度阈值研究

Study on Blasting Vibration Failure Mechanism and Vibration Velocity Threshold of Total Tailing Cemented Backfill

结合五矿矿业安徽李楼铁矿-425 m中段矿柱爆破回采工程实例,利用应力波理论,分析了爆炸应力波在全尾砂胶结充填体中的传播及其与介质界面的相互作用,基于充填体的冲击压剪、剪切和反射拉伸等不同破坏机制和破坏准则,研究了充填体的质点振动速度阈值。研究表明:在爆炸应力波作用下,矿柱与1∶8充填体的胶结面易发生剪切破坏,而胶结充填体易发生压剪破坏;在透、反射应力波作用下,1∶8和1∶20配比充填体的胶结面易发生拉裂破坏,而与1∶20充填体相邻侧的1∶8充填体则可能发生层裂破坏。具体的充填体质点振动速度阈值为:矿柱与1∶8充填体胶结面的剪切破坏质点振速阈值为27.6 cm/s,紧邻矿柱1∶8充填体的冲击压剪破坏质点振速阈值为172 cm/s;1∶8和1∶20配比充填体胶结面的拉裂破坏质点振速阈值为12.6 cm/s,而与1∶20充填体相邻侧1∶8充填体的层裂破坏质点振速阈值为52.6 cm/s。

The pillar blasting stope project of 425 m medium stage in Lilou Iron Mine of Minmetals Mining was presented.Based on the stress wave theory,the propagation of blasting stress wave in total tailing cemented backfill and its interaction with medium interface were analyzed.According to the different failure criteria and mechanism of backfill,such as impact-compression-shear,shear and reflective tension,the particle vibration velocity threshold of backfill were studied.The research shows that the cementing surface between the pillar and the 1∶8 ratio backfill is prone to shear failure due to blast stress wave,and the cemented backfill is prone to compression-shear failure.Under the action of refracted and reflected stress wave,the cementing surface between the 1∶8 ratio and 1∶20 ratio backfill is prone to tensile failure,and the spall fracture of the 1∶8 ratio backfill adjacent to the 1∶20 ratio backfill may occur.The specific particle vibration velocity threshold of the backfill is summarized below:The particle vibration velocity threshold of shear failure on the cemented surface between the pillar and the 1∶8 ratio backfill is 27.6 cm/s;the particle vibration velocity threshold of compression-shear failure of 1∶8 ratio backfill adjacent to pillar is 172 cm/s;the particle vibration velocity threshold of tensile failure on the cementing surface between the 1∶8 ratio and 1∶20 ratio backfill is 12.6 cm/s.the particle vibration velocity threshold of spall fracture of the 1∶8 ratio backfill adjacent to the 1∶20 ratio backfill is 52.6 cm/s.