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采用力学试验手段探究岩石受压情况下内部裂纹扩展贯通机制是了解岩石破坏失稳机制的重要手段。由于无法观察真实岩体内部裂纹扩展过程且CT扫描实时性不足等原因,自行研制了一种各项性质与岩石接近的透明类岩石材料,以观察研究其内部三维裂纹的扩展贯通机制。这一方法克服了真实岩体不透明的特点,可更方便地观察岩体内部裂纹萌生、扩展不同阶段的形状。然后制作了一批内置单裂隙和双裂隙的试件,在RMT-150B多功能全自动刚性岩石伺服试验机上进行单轴压缩试验,详细观察研究了单裂隙和双裂隙试件在不同岩桥角和裂隙间距情况下的裂纹扩展贯通模式以及裂隙数量和间距对试件抗压强度的影响,并从理论方面对翼形裂纹的扩展过程进行了解释。试验表明,在不同的岩桥角和裂隙间距下,次生裂纹将呈现不同的扩展贯通模式,试验中观察到的次生裂纹有张拉翼裂纹、与翼裂纹反向生长的反翼裂纹和拉剪作用下的花瓣状裂纹等,试件最终破坏是各种形式的裂纹汇合贯通的结果。裂隙的存在极大地降低了试件的抗压强度,且随着裂隙数目增加,试件峰值强度呈降低趋势,同时裂隙间距也对试件的峰值强度产生一定的影响。试验成果对分析真实岩体的破坏失稳机制有着重要的参考价值。
It is an important means to understand the instability mechanism of rock failure by using mechanics test to explore the mechanism of internal crack propagation through rock under compressive conditions. Due to the inability to observe the internal crack propagation in the real rock mass and the lack of real-time CT scanning, a kind of transparent rock material with various properties close to the rock was developed to observe and study the mechanism of the expansion of the three-dimensional crack. This method overcomes the opacity of the real rock mass and makes it easier to observe the initiation of cracks in the rock mass and expand the shape of the different phases. Then a series of specimens with built-in single cracks and double cracks were fabricated. Uniaxial compression tests were carried out on the RMT-150B multi-functional fully automatic rigid rock servo testing machine. The effects of single cracks and double cracks on the rockfill angle Crack propagation mode and the number and spacing of cracks on the compressive strength of the specimens were analyzed. The expansion process of the wing crack was explained theoretically. Experiments show that the secondary cracks will show different modes of propagation at different rockfill angles and fissure spacings. The secondary cracks observed in the experiment include the crack of the tension wing, the anti-wing crack and the anti-wing crack Pull the role of the petals under the crack, etc., the ultimate destruction of the specimen is the result of various forms of crack through. The existence of fissures greatly reduces the compressive strength of the specimen, and as the number of fissures increases, the peak strength of the specimen decreases, and the crack spacing also has an impact on the peak strength of the specimen. The test results have important reference value for analyzing the failure mechanism of real rock mass.