高应变率下煤系砂岩力学性能及能量耗散规律研究

发布时间：2018-06-26 13:55

本文选题：高应变率 + 力学性能　；参考：《中国矿业大学》2017年硕士论文

【摘要】：矿山开采过程中,许多情况下围岩处于高应变率的复杂环境中,如矿井的成巷爆破作业、采煤机割煤作业等。高应变率下煤系岩石力学性能及其能量耗散规律研究,是保证矿井围岩稳定性有效控制及安全生产的重要理论基础。本文以煤系砂岩为研究对象,借助分离式霍普金森压杆(SHPB)试验系统,系统研究高应变率下煤系砂岩力学特性及其尺寸效应,并对砂岩破坏过程中的能量耗散特征进行系统分析。主要取得以下研究成果:(1)进行冲击载荷作用下煤系砂岩单轴压缩力学特性试验,利用三波法,获得不同应变率及不同长径比下砂岩应力-应变曲线,并对应力-应变曲线基本特征进行分析;得到不同动态力学特性参数随应变率及长径比的变化规律,如动态弹性模量、动态峰值应力、动态峰值应变等。(2)分析破坏后煤系砂岩试样碎块宏观形态,定性研究不同应变率及长径比下煤系砂岩破坏方式;对破坏后的煤系砂岩试样进行碎块筛分,得到块度分布随应变率及长径比的变化规律;计算破坏后煤系砂岩试样的块度分布参数与分形维数,定量研究冲击载荷作用下煤系砂岩破坏程度的应变率效应与尺寸效应。(3)基于能量耗散的计算原理,分别计算不同应变率及不同长径比下煤系砂岩破坏过程中的各能量,包括入射能量、反射能量、透射能量及耗散能量;研究砂岩破坏过程中能量耗散的应变率效应与尺寸效应,并对砂岩破坏的差异特征进行解释。研究成果可为高应变率环境下煤系岩层结构破坏规律及工程稳定性分析提供重要参考。
[Abstract]:In the process of mining, in many cases, the surrounding rock is in a complex environment with high strain rate, such as mine roadway blasting operation, coal cutting machine cutting operation and so on. The study of rock mechanics performance and energy dissipation law under high strain rate is an important theoretical basis for ensuring the effective control and safety production of the stability of the mine surrounding rock. With the aid of the separation Hopkinson pressure bar (SHPB) test system, the mechanical properties and size effects of coal bearing sandstone under high strain rate are systematically studied and the energy dissipation characteristics during the failure process of sandstone are systematically analyzed. The main results are as follows: (1) the uniaxial compression of sandstone under the impact load is carried out. The three wave method is used to obtain the stress-strain curves of different strain rates and different length to diameter ratios, and the basic characteristics of the stress-strain curves are analyzed. The variation of the dynamic mechanical properties with the strain rate and the length to diameter ratio, such as dynamic elastic modulus, dynamic peak stress, dynamic peak strain, etc., are obtained. (2) The macroscopic morphology of the sandstone specimen after destruction is analyzed, and the failure mode of the coal system sandstone under the different strain rates and the ratio of length to diameter is qualitatively studied. The fragmentation sieving of the sandstone specimen after the destruction is carried out, and the variation of the block distribution with the strain rate and the length diameter ratio is obtained, and the fractal dimension and the fractal dimension of the coal bearing sandstone specimen are calculated and the fractal dimension is calculated. The strain rate effect and size effect of sandstone damage degree under impact load are studied. (3) based on the calculation principle of energy dissipation, the energy, reflecting energy, transmission energy and dissipative energy are calculated, including the incident energy, the reflected energy, the transmission energy and the dissipative energy, and the sandstone failure process is studied by the calculation principle of energy dissipation. The strain rate effect and size effect of medium energy dissipation are used to explain the difference characteristics of sandstone failure. The research results can provide important reference for the failure law of coal bearing strata and the analysis of the stability of the engineering under high strain rate environment.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD313

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