加载速率对充填体强度特性影响的试验研究

摘要

充填体强度是充填采矿技术发展的关键,加载速率变化会对充填体的强度特性产生影响,针对不同灰砂比的充填体试块进行不同加载速率下的单轴抗压强度试验.结果表明:充填体强度随加载速率的增加表现出先上升后下降的现象,存在临界速率使充填体强度最大,低于该临界速率,充填体强度随速率增加而增大,高于该临界速率,试块强度随速率增加反而减小;较快的加载速率限制了充填体内部裂隙和孔隙的发展,降低了其强度弱化效应.同时,较快的加载速率加快了充填体能量的积聚和耗散的过程,缩短了试块进入弹性阶段的时间,并且能使试块在峰前积聚更多的弹性能,更早地达到轴向应力峰值.%The strength of filling body is the key to the development of filling mining technology,and the change of loading rate will affect the strength characteristics of the filling body.Thus,uniaxial compressive strength tests with different cement sand ratio filling block under different loading rates were carried out.Results showed that the strength of filling body firstly increased and then decreased with the increase of loading rate.The maximum strength of the filling body depended on the critical loading rate.Below the critical rate,the strength of the filling body increased with the increase of the rate,but beyond the critical rate,the strength of the test blocks decreased with the increase of the rate.The rapid loading rate limited the development of the internal crack and pore of the filling body,and lowered the strength weakening effect.Meanwhile,the rapid loading rate accelerated the energy accumulation and dissipation process of filling body,shortened the elastic stage of the test blocks.After accumulating more elastic at the pre peak,the test blocks can reach peak axial stress earlier.