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| Interval fracturing of unloading rock-columns and disking mechanisms of rock cores |
| HUANG Houxu1,LV Yaru2,CAI Yi1#br# |
(1. College of Civil Engineering,Anhui Jianzhu University,Hefei,Anhui 230601,China;2. College of Mechanics and Materials,Hohai University,Nanjing,Jiangsu 210098,China)
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Abstract 岩柱的间隔断裂(或岩芯饼化)是由拉应力导致的岩石破坏现象。通过将该类现象统一归结为岩石的自持续断裂,从理论上分析该类现象的发生机制;建立量纲一的饼化厚度d/D与量纲一的初始应力s0/st之间的关系式,且对表达式中各参数的物理意义进行了理论上的解释;并结合已有研究中的实测数据对所求表达式的适用性进行了初步检验。结果表明,当圆柱形花岗岩试样的初始应力为花岗岩抗拉强度的6.85倍及以上时,以一定的速率对岩柱轴向进行卸荷,将导致岩柱内产生与卸荷方向相反的断裂波和与卸荷方向垂直的断裂面;断裂波的波长与饼化厚度直接相关,初始应力越高、卸荷速率越快,断裂波的波长越短、饼化厚度也越小;断裂波随传播而衰减,由于沿岩柱轴向短距离内断裂波的波长变化并不明显,从而造成了饼化厚度在一定范围内依然看似相等的现象。从理论上讲,只要知道了岩柱的初始应力和残余应力,便可直接算出产生饼化现象的量纲一的应力阈值,而如何测量残余应力则有待进一步的研究。
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