某尾矿库勘察中尾矿砂的动强度研究

Study on dynamic strength of tailing ore sand in the exploration of a tailing reservoir

尾矿库用以堆存金属或非金属矿山排出的尾矿或工业废渣,一旦失事,容易造成重特大事故。尾矿库的安全已经成为一项重要研究内容。尾矿主要为细砂、粉砂等无黏性土,常处于饱和状态,在地震作用下容易发生液化并造成尾矿坝的破坏。以某尾矿库为例,采用动三轴的方法对尾矿砂的动力特性进行研究。对土样施加不同的围压,在振动循环条件下使土样达到破坏标准,以得到应力、应变、振动次数关系曲线;应用摩尔-库伦理论,便可以求出土在动力作用下的动黏聚力(c d)与动内摩擦角(φd)的值。试验结果表明:土的动强度随振动次数的增加而降低,随围压的增加显著提高。通过试验得出的动强度参数,给出勘察指导结果,为下一步尾矿库设计提出理论依据。

Tailing reservoir is used to store tailing ore sand and industrial waste discharged from metal or non-metal mines.The instability of tailing reservoir shall cause serious accidents.The safety of tailing reservoir has become an important research project.Tailing materials are mainly non-clay soil,including fine sand,silt and so on.Tailing materials are often in a saturated state,and they are easy to be liquefied and to damage the tailing reservoir.For an example of a tailing reservoir,its dynamic feature is studied by means of dynamic triaxial test.Different confining pressures are applied to the tailing soil sample to make it reach the failure standard under the condition of vibration cycle in order to obtain the relationship curves of stress,strain and vibration times.According to the Mohr-Coulomb theory,the values of Dynamic cohesion(c d)and Internal friction angle(φd)under dynamic action can be obtained.The results show that the dynamic strength of soil sample decreases with the increase of vibration times and positively increases with the confining pressure.Through the test of the dynamic strength parameters,the exploration guidance is given out in the paper,and the theoretical basis is proposed for the design of the tailing reservoir in the future.