透明类岩石预制裂隙不同赋存方式起裂扩展研究

EXPERIMENTAL STUDIES ON PRE-EXISTING CRACK IN DIFFERENT WAYS PROPAGATION AND COALESCENCE IN TRANSPARENT ROCK

岩体受压情况下内部裂纹扩展生长将对岩体稳定性产生重要影响,由于无法直接观察真实岩体内部裂纹起裂扩展过程,研制了一种各项性质与真实岩体接近的透明类岩石材料,在其内部预制裂纹并在RMT-150B多功能全自动刚性岩石伺服试验机上开展单轴压缩力学试验,观察研究其内部裂纹的起裂扩展机理.该方法克服了真实岩石不透明的特点,可以清晰观察到类岩石试件内部的裂纹起裂扩展各阶段的形状及扩展规律.试验中详细观察研究了次生裂纹的起裂扩展规律以及双裂隙试件在不同裂隙间距下的裂纹扩展贯通模式.试验结果表明预制裂隙倾角对次生裂纹的起裂方式将产生一定的影响,双裂隙试件在不同裂隙间距下次生裂纹将呈现不同的扩展贯通模式,实验中观察到了多种形式的裂纹.研究结果同时表明裂隙的存在极大的降低了试件的抗压强度且随着裂隙间距增加试件峰值强度呈降低趋势同时裂隙倾角也对试件的起裂应力产生一定的影响.试验成果对分析真实岩体的破坏失稳机理有着重要的参考价值.

When the rock mass is and pressure,the growth of its internal crack will have an important impact on its stability.Because of the real rock with internal cracks cannot be directly observed,the uniaxial compression tests on transparent rock-like material with internal crack which is developed by myself are done on the RMT-150Bmulti-function automatic rigid rock servo material testing machine to observe and study the mechanism of 3dcracks propagation and coalescence process which are in the transparent rocklike material.The method overcome the character of real rock is not transparent and is convenient to observe the internal crack initiation and propagation rule in the rock mass.In the experiments detailed observe the mechanism of 3dcracks propagation and coalescence process about single crack and the extended through mode of double crack samples with different crack distances.The result show that the angle of the internal crack will have an important impact to the mode of crack initiation and showed that different crack distances will show different failure modes of the double internal cracks specimens,a variety of forms secondary cracks has been found in the experiments.The research also showed that the existence of crack greatly reduces the compression strength of the specimen and the farther the crack distances is:the lower the peak strength is.The crack angle also has an influence on the fracture initiation.The research result offers great reference value to analysis the mechanism of rock damage and instability.