粒径对破碎岩石力学性质影响模型试验研究

地下开采诱发顶板冒落的破碎岩石力学性质直接影响上覆岩层的移动规律.针对破碎岩石力学性质的研究,往往采用理论分析结合室内试验的方法,而室内试验的结果往往与真实现象之间往往存在尺寸效应,并不能直接应用到生产指导中去.本文采用模型试验的方法,对冒落带破碎岩石进行缩尺,利用自主设计的破碎岩石压实仪进行破碎岩石力学特性试验,得到...

Physical Modelling of Particle Size on Mechanical Properties of Broken Rock

The mechanical properties of broken rock with roof caving induced by underground mining directly affect the movement law of overlying strata. For the study of mechanical properties of broken rock, the method of theoretical analysis combined with laboratory test is often adopted, but the results of laboratory test often have size effect with the real phenomenon, which cannot be directly applied to the production guidance. In this paper, the model test method is adopted to scale the broken rock in the caving zone, and the mechanical properties of broken rock are tested by using the self-designed broken rock compactor. The stress-strain relationship of the crushed rock compaction test under four different particle sizes was obtained, and the influence of rock diameter and compaction stress on the compressive strength of crushed rock was analyzed. The results show that the ultimate axial strain increases with the increase of particle size, and the growth rate decreases gradually. The strain growth rate of all rock samples at the initial stage of deformation is higher than that at the later stage of deformation. The initial tangent/secant modulus decreases with the increase of particle size, and the decreasing rate also decreases gradually. With the increase of axial stress, the secant/tangent modulus is more affected by particle size change. When the axial loading stress is the same, the larger the particle size is, the more obvious the change of compaction degree is. With the increase of stress, the compaction degree increases logarithmically.