高应力条件下大理岩真三轴卸载力学特性研究

发布时间：2018-04-24 13:28

本文选题：大理岩 + 真三轴试验　；参考：《昆明理工大学》2017年硕士论文

【摘要】：随着地下矿山开采深度的增加,岩爆对矿业生产的威胁有日益严重的趋势。本文利用真三轴岩爆试验系统模拟深部开采巷道围岩的受力路径,对大理岩进行不同卸载速率下的岩爆试验,从变形特征、力学特性及碎屑特征等方面进行了岩爆特征的研究。主要得到以下结论:(1)通过对大理岩破坏后的应力-应变曲线和力学参数进行分析,发现卸载速率对中间主应变的影响较小;岩爆是由扩容引起的,具有一定的突发性,卸载速率越大产生的扩容现象也就越严重;岩爆时的强度随着卸载速率的降低而增大;由大理岩破坏后的形态可知,不同卸载速率下大理岩破坏后的裂纹与岩样轴向加载方向平行,岩石的破碎程度随着卸载速率的增大而增加,碎屑以片状和条状为主,属于典型的劈裂破坏。(2)由声发射特征分析可知,卸荷速率越大声发射能量值也就越大,在加卸载阶段岩石的声发射能量、计数出现增长现象,声发射计数出现的时间明显早于声发射产生能量的时间;依据RA值及RA-AF散点分布特征分析,得出不同卸载速率下的岩爆试验产生的裂纹均为张剪复合裂纹,破坏时都以张裂纹为主。(3)通过对岩石的碎屑特征分析可知,卸载速率越高产生的粒径小的碎屑颗粒所占的比例也就越高,产生的岩爆也就越剧烈;按长度/宽度/厚度--数量计算的分维数值离散型最小,可作为岩爆碎屑分维值的优先衡量指标;分维值大小与破碎的难度呈正相关性,随着卸载速率的降低其值基本呈减小趋势。基于真三轴岩爆试验系统,对大理岩进行卸载岩爆试验,再现了开挖卸荷诱发岩爆的过程。深入研究了高应力卸荷状态下岩爆的强度、变形特性、声发射特征、碎屑分形特征,研究成果可为今后的岩爆试验研究及实际工程的应用提供借鉴。
[Abstract]:With the increase of mining depth in underground mines, the threat of rock burst to mining production is becoming more and more serious. In this paper, the true triaxial rock burst test system is used to simulate the stress path of surrounding rock in deep mining roadway, and the rock burst test of marble under different unloading rates is carried out. The characteristics of rock burst are studied from deformation characteristics, mechanical characteristics and clastic characteristics. By analyzing the stress-strain curves and mechanical parameters of marbles after failure, it is found that the unloading rate has little effect on the intermediate principal strain, and the rockburst is caused by the expansion of the capacity and has a certain sudden onset. The larger the unloading rate, the more serious the capacity expansion is. The strength of rock burst increases with the decrease of unloading rate. At different unloading rates, the cracking of marble is parallel to the axial loading direction of rock samples, and the degree of rock fragmentation increases with the increase of unloading rate. According to the analysis of acoustic emission characteristics, the louder the unloading rate is, the higher the energy value is, and the increasing phenomenon of acoustic emission energy of rock during loading and unloading stage. According to the analysis of RA value and the distribution characteristic of RA-AF divergence point, it is concluded that the cracks produced in the rockburst test at different unloading rates are tension-shear composite cracks. Through the analysis of the clastic characteristics of the rocks, it can be seen that the higher the unloading rate, the higher the proportion of the smaller grain size and the more violent the rock burst. The numerical discretization of fractal dimension calculated according to length / width / thickness is the smallest, which can be used as a priority index for the fractal dimension of rock burst, and the fractal dimension is positively correlated with the difficulty of fragmentation. With the decrease of the unloading rate, the value of the unloading rate is basically decreasing. Based on the true triaxial rock burst test system, the unloading rockburst test of marble is carried out, and the process of rock burst induced by excavation unloading is reappeared. In this paper, the strength, deformation, acoustic emission and fractal characteristics of rock burst under high stress unloading state are studied. The results can be used for reference in the future experimental research and practical engineering application.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD313

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