【作者】 张勇；

【导师】 李宝玉；

【作者基本信息】 中国矿业大学 ， 工程热物理， 2017， 硕士

【摘要】 煤与瓦斯突出是影响煤矿安全生产最严重的灾害之一,随着开采深度的增加,煤层巷道掘进过程中突出危害越来越严重,传统的防突措施已不能满足矿井安全生产需要,因此,本文提出采用水力冲孔技术消除地应力和排放瓦斯的防突思想,主要研究内容包括以下几个方面:1.建立煤层巷道煤与瓦斯突出受力模型,分析了影响突出的因素;依据Mohr-Coulomb屈服准则,分析了卸压区煤体的稳定性,并且提出释放煤体应力和排放瓦斯是扩大煤体卸压区宽度、消除煤体突出危险性的有效途径。而后分析了卸压后的瓦斯从解吸到逸出到割缝缝槽中的过程,即采取了“解吸—扩散—渗流”的方式进入缝槽。2.从水力冲孔技术及增透机理出发,首先分析了水力冲孔水射流的主要特征。之后对水力冲孔技术破煤机理进行研究,依据动量定理,推导出水射流对煤体表面的总打击力公式,同时总结出水射流打击力与靶距和射流基本参数间的经验方程。最后根据以往实验结果对射流的最大冲击力离喷嘴出口距离进行了分析。3.分析研究喷嘴类型和参数对射流特性的影响,对水力冲孔喷嘴结构和参数进行选型计算,并对水力冲孔喷头体结构图进行了设计。而后对喷嘴出口水射流压力及水力冲孔破煤压力进行了计算,最后确定喷嘴的结构尺寸。4.利用FLUENT软件对水力冲孔喷头体的内部流场进行数值模拟,并采用FLAC3D软件对水力冲孔后的卸压效果进行模拟。水力冲孔的扩孔增透作用主要体现在:首先,冲出大量煤体,为煤体膨胀变形提供了充分的空间,使地应力向四周扩散,起到局部卸压作用。其次,在冲出煤体的过程中排出大量瓦斯,由于煤体的膨胀变形,煤层的透气性增加,扩大了瓦斯抽采影响半径,达到理想的抽采效果。最后,冲孔扩孔还增加了煤体裸露表面积,孔洞周围形成大量裂隙,增加单位时间抽采量,缩短预抽时间。5.在大平矿工作面进行水力冲孔技术现场试验,并观察水力冲孔后出煤量和排放瓦斯的防突效果。冲孔完成后,孔洞周围一定范围内煤体应力得到释放,瓦斯排放效果显著;工作面前方煤体产生位移,集中应力向深部转移,突出危险性得到降低或消除。综述所述:水力冲孔技术作为一种有效的防突措施,通过释放煤体应力和排放瓦斯,对煤体进行有效卸压,较明显的起到了防止煤与瓦斯突出的作用。更多还原

【Abstract】 The coal and gas outburst is one of the most serious disaster in coal mine safety production.With the increasing of mining depth,the outburst danger is more and more serious during the tunneling of coal seam.The traditional outburst prevention methods can not meet the needs of the safety production in coal mine.Therefore,this paper proposes the use of hydraulic punching technology to eliminate stress and gas outburst prevention,the main research contents include the following aspects:1.The establishment of the force model of coal and gas outburst in coal seam tunnel,the thesis analyzes the impact factors in the development process of outburst.Based the Mohr-Coulomb yield criterion,the stability of the stress-released zone is analyzed,and the thesis points out that trying to release coal stress and exhaust gas adequately is the effective way to extend the width of the stress-released zone and eliminate outburst risk.Then the structural characteristics of coal are analyzed,the structure of coal is divided into pore and fissure structure,and through the analysis of the permeability of coal,the coal seam permeability function is introduced and the factors that influence the infiltration capacity are introduced.2.Based on the hydraulic punching technology and the mechanism of increasing penetration,the main characteristics of hydraulic punching water jet are analyzed.Then,based on the momentum theorem,the formula of the total blow force of the water jet on the surface of the coal body is deduced.At the same time,the combat force and the target parameters of the jet and the basic parameters of the jet are summarized.Between the empirical equation.And then analyze the process of gas from desorption to escape to cutting seam slot after stress-released,which took the way of “desorption-diffusion-seepage” into the cutting seam slot.3.The influence of the nozzle type and parameters on the jet characteristics is analyzed and the design and calculation of the hydraulic punching nozzle structure are carried out,and the hydraulic punching nozzle body is designed.And then the nozzle water jet pressure and hydraulic punching coal pressure was calculated,and finally determine the size of the nozzle structure.4.The FLUENT software was used to simulate the internal flow field of of the hydraulic punching nozzle body and the pressure relief effect after hydraulic punching was simulated by FLAC3 D software.The effect of hydraulic perforation is mainly reflected in the following: First,out of a large number of coal,providing sufficientspace for the expansion of coal deformation.The stress spread around,play local relief role.Secondly,in the course of the out of the coal out of a large number of gas,due to the expansion of coal deformation,coal permeability increased,expanding the radius of gas extraction,to achieve the desired extraction effect.Finally,the punching hole also increases the bare surface area of the coal body,forming a large number of cracks around the hole,increasing the pumping time per unit time and shortening the pre-pumping time.5.In the Daping Mine working surface,the hydraulic punching technology was tested in the field,and the effect of the amount of coal produced after the hydraulic punching and the outburst of the discharged gas were observed.After the punching is completed,the stress of the coal body is released within a certain range around the hole,and the gas emission effect is remarkable.The displacement of the coal in the working face is shifted and the concentrated stress is transferred to the deep,and the danger is reduced or eliminated.In summary,as a kind of effective outburst prevention measure,through trying to release coal stress and exhaust gas adequately,the technology of the hydraulic punching technology plays a key role for outburst prevention.更多还原