注水对软煤固结力学性质影响的试验研究
发布时间：2018-08-03 17:32
【摘要】：本文通过分析国内外煤层注水改良煤体力学性质的研究现状基础之上,运用强度理论和液桥力理论,从宏观和微观的角度,分析了合理注水增强粉煤固结力学性质的机理。通过试验及理论分析,总结了型煤在不同含水率条件下力学性质的变化规律。结合现场试验考察,验证了松软煤壁合理注水后,煤壁板结效果增强,有效的防止松软煤壁的大范围片帮。本文研究主要内容及结论如下:1.结合现场考察和试验,对制备型煤的原煤样基础参数进行分析。得出采集的煤样具有含水率低,强度低的,易破碎的特点,符合本文的研究要求。根据理论分析与试验,确定了型煤制备过程的成型压力和粒径配比,利用自行研制的型煤模具,加工制备了具有不同含水率的型煤。2.利用RMT-150B型岩石力学试验系统对已制备的不同含水率的型煤试样进行单、三轴压缩试验,通过试验结果分析型煤在不同含水率条件下力学性质的变化规律。试验结果表明在单轴压缩条件下,随着型煤成型水分的增大,型煤试样的单轴抗压强度和弹性模量呈现先增大后减小的趋势,而泊松比随着成型水分的增大呈现先减小后增大的趋势。当煤样的成型水分含量在7%左右时,单轴抗压强度最大为0.821MPa,弹性模量最大值为1.332GPa,泊松比处于最小值,为0.267。在不同围压的三轴压缩的条件下,随着围压的增大,型煤的抗压强度随之增大。利用强度准则,求出不同含水率型煤的内聚力和内摩擦角,结果显示,随着含水率的增大,型煤的内聚力和内摩擦角先增大后减小。3.通过湿煤颗粒作用力的微观分析,在微观作用力中湿颗粒间的液桥力对颗粒的影响最大。通过分析液桥力模型,分析不同含量水分影响湿煤颗粒固结的作用机理。并且对颗粒间影响的液桥力的因素进行分析。丰富了煤体固结的理论,为煤层合理注水固结粉煤,为防止粉煤类工作面片帮提供了微观理论依据。4.论文研究中,对朱仙庄煤矿的Ⅱ863综采放顶煤工作面进行了煤壁浅孔注水试验研究。通过对煤层注水湿润效果的测定及考察,得出注水有效影响范围测定为横向6m,纵向1.0-1.2m。实施煤壁浅孔注水后,距底板1.0-3.6m范围内煤体的含水量大大提高,煤体被较好地润湿,为形成一定厚度的粘结层创造了有利条件,对防止煤壁片帮起到关键性作用通过现场考察,注水后煤壁片帮得到有效控制。
[Abstract]:In this paper, based on the analysis of the present situation of improving the mechanical properties of coal body by coal seam water injection at home and abroad, using strength theory and liquid bridge force theory, the mechanism of reasonable water injection to enhance the consolidation mechanical properties of pulverized coal is analyzed from the macroscopic and microscopic angles. Through experiment and theoretical analysis, the change law of mechanical properties of briquette under different moisture content is summarized. Combined with the field test, it is proved that after reasonable injection of soft coal wall, the effect of coal wall panel junction is enhanced, and the large scale flake of soft coal wall is effectively prevented. The main contents and conclusions of this paper are as follows: 1. Based on field investigation and test, the basic parameters of raw coal sample prepared from briquette were analyzed. It is concluded that the collected coal samples have the characteristics of low moisture content, low strength and easy breakage, which accord with the research requirements of this paper. According to the theoretical analysis and experiment, the forming pressure and particle size ratio of briquette preparation process were determined, and the briquette coal with different moisture content was prepared by using the molded coal mould developed by ourselves. The uniaxial and triaxial compression tests of briquette samples with different moisture content were carried out by using RMT-150B rock mechanics test system. The variation of mechanical properties of briquette under different moisture content was analyzed by test results. The experimental results show that the uniaxial compressive strength and elastic modulus of briquette samples increase first and then decrease with the increase of briquette forming moisture under uniaxial compression condition. The Poisson's ratio decreases first and then increases with the increase of molding moisture. When the moisture content of the sample is about 7%, the uniaxial compressive strength is 0.821 MPA, the modulus of elasticity is 1.332 GPA, and the Poisson's ratio is at the minimum of 0.267. Under the condition of triaxial compression with different confining pressures, the compressive strength of briquette increases with the increase of confining pressure. The cohesion and friction angle of briquettes with different moisture content were calculated by using the strength criterion. The results showed that the cohesion and friction angle of briquette increased first and then decreased by 0.3 with the increase of moisture content. According to the microscopic analysis of the wet-coal particle force, the influence of the liquid bridge force between the wet particles on the particle is the greatest. By analyzing the liquid bridge force model, the mechanism of the effect of moisture content on the consolidation of wet coal particles is analyzed. The influence factors of liquid bridge force between particles are analyzed. It enriches the theory of coal body consolidation, provides microscopic theoretical basis for rational water injection of coal seam to consolidate pulverized coal, and provides micro theoretical basis for preventing coal face. In this paper, the water injection test of shallow hole in coal wall of 鈪，
本文编号：2162469
[Abstract]:In this paper, based on the analysis of the present situation of improving the mechanical properties of coal body by coal seam water injection at home and abroad, using strength theory and liquid bridge force theory, the mechanism of reasonable water injection to enhance the consolidation mechanical properties of pulverized coal is analyzed from the macroscopic and microscopic angles. Through experiment and theoretical analysis, the change law of mechanical properties of briquette under different moisture content is summarized. Combined with the field test, it is proved that after reasonable injection of soft coal wall, the effect of coal wall panel junction is enhanced, and the large scale flake of soft coal wall is effectively prevented. The main contents and conclusions of this paper are as follows: 1. Based on field investigation and test, the basic parameters of raw coal sample prepared from briquette were analyzed. It is concluded that the collected coal samples have the characteristics of low moisture content, low strength and easy breakage, which accord with the research requirements of this paper. According to the theoretical analysis and experiment, the forming pressure and particle size ratio of briquette preparation process were determined, and the briquette coal with different moisture content was prepared by using the molded coal mould developed by ourselves. The uniaxial and triaxial compression tests of briquette samples with different moisture content were carried out by using RMT-150B rock mechanics test system. The variation of mechanical properties of briquette under different moisture content was analyzed by test results. The experimental results show that the uniaxial compressive strength and elastic modulus of briquette samples increase first and then decrease with the increase of briquette forming moisture under uniaxial compression condition. The Poisson's ratio decreases first and then increases with the increase of molding moisture. When the moisture content of the sample is about 7%, the uniaxial compressive strength is 0.821 MPA, the modulus of elasticity is 1.332 GPA, and the Poisson's ratio is at the minimum of 0.267. Under the condition of triaxial compression with different confining pressures, the compressive strength of briquette increases with the increase of confining pressure. The cohesion and friction angle of briquettes with different moisture content were calculated by using the strength criterion. The results showed that the cohesion and friction angle of briquette increased first and then decreased by 0.3 with the increase of moisture content. According to the microscopic analysis of the wet-coal particle force, the influence of the liquid bridge force between the wet particles on the particle is the greatest. By analyzing the liquid bridge force model, the mechanism of the effect of moisture content on the consolidation of wet coal particles is analyzed. The influence factors of liquid bridge force between particles are analyzed. It enriches the theory of coal body consolidation, provides microscopic theoretical basis for rational water injection of coal seam to consolidate pulverized coal, and provides micro theoretical basis for preventing coal face. In this paper, the water injection test of shallow hole in coal wall of 鈪，
本文编号：2162469
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