不同围压下黄砂岩力学特征与声发射特征

摘要

To study the mechanical characteristics of yellow sandstone under different confining pressures, acoustic emission characteristics and rock fracture morphology, using ROCK 600-50 rock tri-axial rheological apparatus and acoustic emission system to carry out the conventional tri-axial test for yellow sandstone, to study the peak stress, peak strain, residual strength and mode of post-embedded of yellow sandstone in different confining pressures and discuss the evolution of acoustic emission counting in yellow-sandstone fracture process. The results show that: the peak stress, axial peak strain and residual strength of yellow sandstone specimens increase with the increase of confining pressure; the influence of confining pressure on radial peak strain is weaker; through the analysis of acoustic emission counting, yellow sandstone damage degree is more intense with the increase of confining pressure, and secondary or multiple failures may occur. Confining pressure reduces the number of yellow sandstone main cracks in the process of failure, and significantly inhibits the production of the secondary cracks.%为研究不同围压下黄砂岩的力学特征、声发射特征和岩石破裂形态,采用ROCK 600-50型岩石三轴流变仪与声发射系统对黄砂岩进行常规三轴试验,研究不同围压下的黄砂岩的峰值应力、峰值应变、残余强度及破坏形态变化特征,讨论了黄砂岩破裂过程声发射计数演化规律.结果表明:黄砂岩试件的峰值应力、轴向峰值应变和残余强度均随围压的增加而增大,围压对径向峰值应变影响较弱,通过对声发射计数分析,黄砂岩破坏程度随围压增大更加剧烈,会出现二次或多次破坏,围压减少了黄砂岩破坏过程中主裂纹数目,并明显抑制了次生裂纹的产生.