岩石力学试验中缺陷岩样抗压强度修正方法

由于岩石形成过程以及所经历的地质历史作用,岩石内部微观裂纹、裂隙、孔隙等缺陷是客观存在的,而这些缺陷正是导致岩石力学试验结果离散的根本原因。在以往岩石力学试验现象统计分析基础上,详细分析了岩石内部缺陷对应力-应变曲线的影响,提出了显式缺陷和隐式缺陷岩样的概念;结合岩石的地质本质性和室内试验条件,选取岩石的密度和纵波波速作为衡量岩样缺陷程度和强度预测的基本参数,建立了岩石纵波波速、密度和抗压强度预测经验公式;针对显式缺陷和隐式缺陷岩样的试验结果分别提出了抗压强度修正方法,该修正方法的核心就是采用纵波波速和密度作为衡量岩样内部缺陷的定量指标,将岩样的缺陷修正到同一水平,这样将更好地把握岩石力学试验的规律。验证结果表明,所提出的修正方法可以较好地修正由于岩样内部缺陷导致的抗压强度离散值。

Compressive Strength Correction Method of Flaw Sample in Rock Mechanics Test

Because of rock formation process and experienced geological history effects,internal micro-cracks,crevices,porosity and other flaws objectively exist in rock.These flaws are exactly the root causes resulting in discretization in rock mechanics test.On the basis of massive analysis of rock mechanics test phenomenon,effects of internal flaw on rock stress-strain curve were detailed analyzed,and conceptions of explicit flaw rock samples and implicit flaw rock samples were proposed;Combined with the geological nature of rock and laboratory test conditions,rock density and longitudinal wave velocity were selected as basis parameters to measure rock sample flaw degree and to predict rock sample strength,and rock longitudinal wave velocity,density and compressive strength prediction empirical formulas were established;Compressive strength correction methods were separately proposed for the explicit and implicit flaw rock samples,and the core of the correction method was to use a longitudinal wave velocity and density as quantitative indexes to measure internal flaws of the rock samples,to modify the rock sample flaws to the same level,which can better grasp the rules of rock mechanics test.Practice shows that the proposed correction method can better modify the compressive strength dispersion resulted by the internal flaws in the rock samples.