单轴压缩条件下含双圆孔类岩石试样力学特性的细观研究

发布时间：2018-01-23 20:37

本文关键词： 岩石力学单轴压缩力学特性颗粒流　出处：《岩石力学与工程学报》2017年11期 　论文类型：期刊论文

【摘要】：圆孔作为一种典型的岩石缺陷,对岩石的力学特性具有重要影响。采用室内试验及PFC2D程序,构建含双圆孔类岩石试样并对其进行单轴压缩试验,研究其不同圆孔间距、倾角组合条件下的强度、裂纹模式及破裂孕育演化特征。研究表明:(1)当间距不变时,随倾角的增大,试样单轴抗压强度呈先减小后增大的趋势,且在倾角为45°~60°时达到最低单轴抗压强度;当倾角为90°恒定时,随间距的增大,试样单轴抗压强度呈先增大后减小的趋势,且在间距为40 mm左右时达到最大单轴抗压强度。(2)试样产生的裂纹类型可分为I型(张拉型)裂纹、II型(剪切型)裂纹、III型(混合型)裂纹等三类。当孔距较近时,随倾角的增大,圆孔间裂纹类型逐渐由III型裂纹转变为II型裂纹,两圆孔靠近加载端部一侧的孔壁逐渐产生I型裂纹,靠近试样两侧边界处的孔壁始终会产生II型裂纹。当倾角为90°恒定时,随间距的增大,两孔间相互作用减弱,但两圆孔靠近加载端部一侧及靠近试样两侧边界处的孔壁,始终分别产生I型裂纹和II型裂纹。(3)两孔间岩桥连线上的II型裂纹首先产生,其次在圆孔靠近加载端部一侧的孔壁产生I型裂纹,最后在圆孔靠近试样两侧边界处的孔壁产生II型裂纹。通常构成II型裂纹的声发射事件破裂强度,高于构成I型裂纹的声发射事件破裂强度。
[Abstract]:As a typical rock defect, circular pore has an important influence on the mechanical properties of rock. Laboratory test and PFC2D program are used to construct the specimen containing double circular pore and carry out uniaxial compression test. The strength, crack mode and fracture evolution characteristics of different circular hole spacing, dip angle combination condition are studied. The results show that when the spacing is constant, the crack pattern increases with the inclination angle. The uniaxial compressive strength of the sample decreases first and then increases, and reaches the lowest uniaxial compressive strength when the inclination angle is 45 掳~ 60 掳. When the inclination angle is 90 掳, the uniaxial compressive strength of the specimen increases first and then decreases with the increase of the distance. The crack types of specimens with maximum uniaxial compressive strength of about 40 mm can be divided into mode I (tensile mode) cracks and mode II (shear mode) cracks. When the hole distance is near, with the increase of inclination angle, the type of crack between circular holes gradually changes from III mode crack to mode II crack. A mode I crack is gradually produced in the hole wall near the loading end side of the two round holes, and a mode II crack is always produced in the hole wall near the boundary of both sides of the specimen. When the inclination angle is 90 掳, the crack will increase with the increase of the distance. The interaction between the two holes is weakened, but the two round holes are near the side of the loading end and the pore wall near the boundary of both sides of the specimen. The mode II cracks on the rock bridge line between the two holes, mode I crack and mode II crack respectively, are produced first, and then on the wall of the hole near the loading end of the round hole. Finally, the mode II crack is produced in the hole wall near the boundary of both sides of the specimen, and the AE event rupture intensity of the mode II crack is usually higher than that of the mode I crack.
【作者单位】：北京科技大学金属矿山高效开采与安全教育部重点实验室;中国电建路桥集团有限公司;中铁十六局集团有限公司;
【基金】：国家青年科学基金资助项目(51504016) 科技北京百名领军人才培养工程(Z151100000315014) 中央高校基本科研业务费专项资金资助项目(FRF TP 16 021A3)~~
【分类号】：TU45
【正文快照】： 作为天然的非均质工程地质材料,岩石内部含有许多宏观和细观的裂隙、孔洞等缺陷。岩石的力学特性与其内部缺陷的形状、大小、几何分布等均有密切的联系,其裂纹起裂、扩展、搭接、贯通等过程受岩石缺陷的影响较大。因此,深入开展缺陷对岩石破裂机制及演化规律影响的研究,一直以

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