逐级加卸载扰动下脆性岩石加卸载响应比试验研究

以某金属矿山隔离矿柱回采为工程背景,取该矿典型矿岩进行单轴和三轴逐级加卸载扰动试验,研究逐级加卸载扰动模式下,利用加卸载响应比预测岩石变形破坏方法。研制了可实现声发射便捷定位的加载转换装置,解决了三轴腔表面定位存在的干扰和信号削弱等问题。试验结果表明:以轴向应变、声发射能量作为响应参数,可反映岩石变形破坏过程;单次效应和扰动平均效应2种计算方法下加卸载响应比(LURR)均存在随荷载增加而增大的趋势,但后者不如前者明显。

An Experimental Study on Load/Unload Response Ratio of Brittle Rocks Under Graded Load / Unload Disturbance

With the stopping of barrier pillars in metal mines the engineering background, a graded load-unload disturbance test of typical rocks has been conducted under uni-axial and conventional triaxial compression, with load / unload response ratio (LURR) theory applied in prediction of rock deformation and failure. An apparatus for loading conversion has been designed for the location of acoustic emission (AE), thus overcoming the interruption and reduction of AE signals in the process of the location of the surface of triaxial cavity. Experimental results show that, with axial strain and acoustic emission energy the LURR parameters, the deformation and failure process of rocks can be best reflected. Compared with two calculation methods including single and accumulation ones, LURR presents increment along with an increase in load, nevertheless, with the latter not so obvious as the former.