CAJ | 학술논문

利用自主研发的煤岩双面剪切细观开裂演化过程试验装置，通过开展不同法向应力条件下的剪切试验，借助声发射技术及图像处理技术，对细观开裂扩展过程、细观开裂扩展空间分布进行深入探究。研究结果表明：对于压剪应力条件下的双面剪切试验，加载过程中的大部分阶段，试件表面损伤不明显，表面裂纹出现在峰值剪应力之前；当剪应力达到峰值前，Hit 率有一个急剧增加的过程，说明砂岩内部已有裂纹产生，而试件表面并无明显变化，一段时间后才在表面观测到细小裂纹，推测裂纹由内向外扩展；试件发生宏观破坏后，左右两侧裂纹呈八字形或梯形分布，由于竖向剪切力引起的岩体内部剪切破坏占主导作用且砂岩内部晶粒间存在一定的几何物理性质差异，主裂纹基本沿预定剪切面扩展的同时表现出开裂扩展的不规则性；裂纹多在石英、长石等矿物颗粒的边缘即砂岩中相对薄弱的环节产生，随着应力水平的增加，裂纹也会穿过矿物颗粒形成穿晶破裂，这种现象多在石英颗粒中出现，这与其特有的微结构特征有关。
이용자주연발적매암쌍면전절세관개렬연화과정시험장치，통과개전불동법향응력조건하적전절시험，차조성발사기술급도상처리기술，대세관개렬확전과정、세관개렬확전공간분포진행심입탐구。연구결과표명：대우압전응력조건하적쌍면전절시험，가재과정중적대부분계단，시건표면손상불명현，표면렬문출현재봉치전응력지전；당전응력체도봉치전，Hit 솔유일개급극증가적과정，설명사암내부이유렬문산생，이시건표면병무명현변화，일단시간후재재표면관측도세소렬문，추측렬문유내향외확전；시건발생굉관파배후，좌우량측렬문정팔자형혹제형분포，유우수향전절력인기적암체내부전절파배점주도작용차사암내부정립간존재일정적궤하물이성질차이，주렬문기본연예정전절면확전적동시표현출개렬확전적불규칙성；렬문다재석영、장석등광물과립적변연즉사암중상대박약적배절산생，수착응력수평적증가，렬문야회천과광물과립형성천정파렬，저충현상다재석영과립중출현，저여기특유적미결구특정유관。
The mesoscopic test device developed studying the crack process of coal and rock under double shear was used in the shear test at different stress conditions. The acoustic emission and image processing techniques were employed to measure the mesoscopic cracking propagation process and the mesoscopic cracking extension space distribution. For the double shear test under compression and shearing,the damage of the surface of the specimen is not visible in most of the period of loading process and the surface cracks occur just before the shear stresses reach the peak value. When the shear stresses are nearly reaching the peak,the rate of Hit has a sharp increase indicating that there are already cracks inside the sandstone,while on the surface there are no cracks,and the tiny cracks can only be seen after a period of time. Presumably,the cracks developed from inside to outside. After the macroscopic damage,the left and right sides of cracks show a splayed or trapezoidal distribution. Because the internal shear failure of rock mass is mainly caused by the vertical shear force and the sand grains possess the different geometric and physical properties,the main crack along the shear plane extended irregularly. Cracks always occur in the edges of mineral particles like quartz,feldspar etc which are the weakest links of sandstone. As the shear stress level increases,the cracks will cross over the mineral particles and form transgranular fractures. This phenomenon is often seen in quartz grains because of its specific relevant microstructure features.