不同围压下花岗岩σ_(cc),σ_(ci)和σ_(cd)的确定

Experimental Study on the Determination Method of σ_(cc),σ_(ci) and σ_(cd) for Granite Under Different Confining Pressures

为研究不同围压下裂隙闭合应力阈值σcc,起裂应力阈值σci和损伤应力阈值σcd,对髙放废物地质处置新疆预选场址雅满苏YM01号钻孔岩心进行了三轴压缩试验和巴西劈裂试验.应用裂隙体积应变模型、移动点回归法和声发射确定了σcc,σci和σcd;通过分析不同方法确定各阈值的适用性,优化了一套确定各阈值的综合方法;分析了不同围压下σcc,σci和σcd与围压的关系：σcc受围压的影响不明显,σcc=σ1=50-65MPa;σci为裂隙张拉破坏的起点,起裂强度满足格里菲斯强度理论;σcd与峰值抗压强度σc线性关系明显,损伤强度满足摩尔-库伦强度理论.

The determination of the stress thresholds of crack closure（ σcc）,crack initiation（ σci） and crack damage（ σcd ）of rock is of great significance for understanding the progressive failure process of rock from high-level radioactive geological waste repository. The Brazilian test and triaxial compression test are performed to determine those stress thresholds. Three methods including moving point regression technique,crack volumetric strain and acoustic emission hits rate are applied to determine these thresholds mentioned above. A comprehensive method is proposed to determine stress thresholds accurately and conveniently. The relationship of various thresholds and corresponding confining pressure are also analyzed,results showthat σcc is less sensitive to confining pressure compared with the crack damage stress σcd,the crack initiation strength（ σci ）meets Griffith strength theory,which is confirmed by the tensile strength from Brazilian test.