【作者】 李晓泉；

【导师】 尹光志；

【作者基本信息】 重庆大学 ， 安全技术及工程， 2010， 博士

【摘要】 煤与瓦斯延期突出占总的突出事故的比例不大,但由于其发生具有延时性、隐蔽性,发生突出时可能是人员正在作业,使得突出发生时猝不及防,危害极大。本文利用ASAP 2020 V3.01 H型分析仪、HCA型高压容量法吸附装置、岛津AGI-250kN型电伺服试验机、MTS815岩石力学伺服系统、自主研制的“含瓦斯煤热流固耦合三轴伺服渗流系统”和“大型煤与瓦斯突出模拟试验台”在实验室进行了一系列实验,在天府矿业有限责任公司三汇一矿2124采煤工作面进行了钻屑量与矿山压力、瓦斯压力关系现场试验。根据各种试验结果分析,从采掘工作面卸压区煤岩体失稳破坏的能量判据、力学判据、局部扰动破坏判据和时空机制等方面入手,得出煤与瓦斯延期突出机理。取得了如下主要研究成果:1.延期突出煤具备突出煤的吸附特性,具有较强的吸附能力,同时具备非突出煤的力学强度特性,即具有较高的煤体强度,这可能是发生煤与瓦斯延期突出的重要原因之一。2.通过煤的力学试验,建立了煤样在常规单轴压缩、三轴压缩状态下的损伤本构方程:围压和煤样的弹性模量之间存在对数函数关系;煤样在屈服点后的实测值得出损伤变量和轴向应变呈对数函数关系。3.针对三轴压缩状态下瓦斯在煤样中的渗透特性,在考虑变形对渗透率的影响情况下,对达西定律公式进行了修正,并与不考虑煤样的变形直接计算的瓦斯渗透率,最大偏差可达20%以上,所以在研究煤的渗透特性时应考虑变形对渗透率的影响。4.通过在三轴压缩状态下煤样瓦斯渗流试验,得出了煤样的渗流特性,并建立了有效应力和渗透率的关系方程:作用在延期突出煤样上的有效体积应力和渗透率为负指数关系。5.通过延期突出煤在循环载荷状态下的瓦斯渗流试验,得出了煤样渗透率变化率和损伤变量沿同方向变化,前几个循环变化较为明显,经过几个循环后,数值趋于稳定,表明渗透率变化率与煤样的损伤程度有关。6.通过天府矿业有限责任公司三汇一矿2124采煤工作面现场试验,得出突出煤层长壁工作面钻屑量与矿山压力、瓦斯压力之间存在正相关关系。7.通过煤与瓦斯延期突出模拟试验结果得出:煤与瓦斯延期突出是地应力和瓦斯压力共同作用的结果,采掘作业破坏了煤层原岩应力平衡,引起地应力重分布,使煤岩裂隙发育,煤层中吸附瓦斯解吸为游离瓦斯,使煤体内瓦斯压力增大,封堵软弱分层的硬煤岩体在瓦斯压力和地应力共同作用下发生破坏,在瓦斯膨胀能作用下引起突出。突出强度受瓦斯压力影响较大,而突出强度反映发生延期突出时破坏程度,即搬运突出煤粉的能量主要是由瓦斯膨胀能提供的。8.根据实验室试验和现场实验成果,对煤与瓦斯延期突出概念进行了重新定义,并从煤与瓦斯延期突出的能量来源、煤岩力学失稳破坏条件、外力扰动影响、时空转换机制等方面入手,得出延期突出机理。更多还原

【Abstract】 In general case, coal and gas delay outbursts account for a small proportion of total outburst accidents. But they are very harmful because their occurrences are delayed and invisible, the workers are possibly working and have no time to prevent them. A series of experiments were carried out by ASAP 2020 V3.01 H Surface Area and Porosity Analyzer, HCA High Pressure Volumetric Method Adsorption System, AGI-250kN SHIMADZU, MTS815 Rock Mechanics Test System, self-made“Gassy Coal THM Coupling System”and“the large-scale test device for coal and gas outburst simulation”in this dissertation. The field experiment studying the relationship of ground pressure, gas pressure and value of drilling cuttings weight is carried out at 2124 fully mechanized coal mining face of Sanhui mine in Tianfu Mining Company. Based on the analysis of all experiment results, we can obtain the mechanism of coal and gas delay outburst according to the energy criterion, mechanics criterion, failure criterion of local disturbance and space-time mechanism of unstable failure on coal and rock of distressed zone at mining and tunneling face. The main research results are as follows:1. The delay outburst coal samples have strong adsorption capacity as same as the outburst coal samples and mechanical strength as same as of non-outburst coal samples. It may be one of the important reasons inducing coal and gas delay outburst.2. The damage constitutive equations of vertival stress-strain of coal samples are respectively established under the conditions of uniaxial compression and triaxial compression based on the mechanical experiment. The confining pressure and elastic modulus of coal samples exist in logarithmic function relationship. The damage variable and axial strain of measured values after the yield point of coal samples exist it too.3. We have modified Darcy Law formula considering the influence that deformation exerts on the permeability of coal samples under the triaxial compression. Comparing with the condition that neglecting the deformation’s effect, the maximum deviation is more than 20%. Therefore, we should consider it.4. The relationship equations of effective stress and permeability are established and the seepage properties of coal samples are obtained by the gas seepage experiment of coal samples under the triaxial compression. The effective volumetric stress and permeability of the delay outburst coal samples exist in negative exponent relationship.5. The change direction of permeability rate and damage variable is same by the gas seepage experiment of delay outburst coal samples under cyclic loading. The change of the permeability rate and damage variable is very obvious at the first few cycles, but tends to be stable after several cycles. It shows that the permeability rate is related to the damage degree.6. The positive relationship of ground pressure, gas pressure and value of drilling cuttings weight drilling cuttings weigh and ground pressure, gas pressure is derived by the field experiment based on 2124 fully mechanized coal mining face of Sanhui mine in Tianfu Mining Company.7. The results of the simulation experiment show that coal and gas delay outburst is the result of both ground stress and gas pressure interaction. The prepare process of outburst can describe to the balance of original rock stress broken by mining work, ground stress distributing again, the coal and rock fracture development, adsorption gas in coal seam desorbing to free gas, gas pressure increasing, the hard coal and rock of plugging weak lamination broken by gas pressure and ground stress and outburst happened by gas swelling power. The critical gas pressure influences the outburst intensity which reflects damage degree at delay outburst. The energy of transportation outburst coal power is provided mainly by gas expansion energy.8. Based on above-mentioned studies, We redefine the conception of coal and gas delay outburst. We can obtain the mechanism of coal and gas delay outburst according to the energy criterion, mechanics criterion, failure criterion of local disturbance and space-time mechanism of unstable failure on coal and rock of distressed zone at mining and tunneling face.更多还原