The study of acoustic emission （AE） forecasting coal and rock disaster technique

Introduced the coal and rock AE propagation rule, wave guide fixing technics on AE sensors, and AE forecasting coal and rock disaster on the scene and so on. The coal and rock AE propagation rule that follows the exponent attenuation function on different AE frequencies, different quality factors and different propagation distances were analyzed and deduced by theory, numerical simulation, and by actual experiment. Consequently, it was deduced that the coal and rock AE propagation rule follows the exponent attenuation function. Based on the correlative theory of wave dynamics and AE sensor, the AE wave guide propagation mechanical model on the sensor fixing manner is found, and the relations of displacement and speed and acceleration between the AE signal source and the AE signal receiving terminal are presented. The effect of the AE sensor fixing manners on coal and rock surfaces, coal and rock bottoms and wave guides were studied by actual experiment. For the results, the effect of the AE sensor fixing manner on wave guides is better than on coal and rock surfaces, and was equivalent to the fixing manner on coal and rock bottoms. Based on the above study results, actual coal and rock dynamistic disasters were successfully forecasted. Supported by the Project of National Basic Research Program of China (973 Program) (2005CB221505); the Significant Project of National Natural Science Fund (50534080/E041503); the Project of Coal Mine Gas and Fire Hazard Prevention Major Lab in Henan Province (HKLGF200508)     

基于MATLAB的抽放钻孔周围瓦斯流动数值模拟

在测试某矿井瓦斯压力、瓦斯流量、瓦斯吸附常数、瓦斯渗透率、瓦斯含量系数等基础参数的基础上,采用MATLAB偏微分方程工具箱对该矿井瓦斯抽放钻孔在不同抽放半径、不同抽放负压下的瓦斯流动进行了二维计算,得出了抽放钻孔在不同时间的影响半径、流量与时间的关系及钻孔半径和抽放负压对煤层瓦斯压力分布及抽放流量的影响规律,并与实际进行了比较结果表明,采用MATLAB偏微分方程工具箱能够准确模拟抽放钻孔有效半径,预测瓦斯流量,是现场工程技术人员一种便捷的方法.     

多因素叠加作用下煤储层渗透率的动态变化规律

分析了煤储层渗透率的主要影响因素,讨论了有关黏性渗流的基本理论问题。在不同轴压、围压和气体压力梯度下,对山西晋城矿区原状无烟煤煤样进行了三维应力场的CH 4渗流实验,计算并分析了有效应力、煤基质收缩、气体滑脱效应等因素对渗透率的影响及其叠加作用的表现。认为吸附态的CH 4分子组成了煤储层孔-裂隙气体渗流的边界层,滑脱效应存在于边界层以外,煤储层渗透率的动态变化是有效应力、煤基质收缩效应和滑脱效应叠加作用的结果,渗透率在压力梯度0～0.1 MPa阶段衰减最为显著,滑脱效应对渗透率的贡献远小于基质收缩效应,且随着压力梯度的增大而几乎可以忽略。     

Effectiveness analysis of methane-drainage by deep-hole controlled pre-splitting blasting for preventing coal and gas outburst

In the study of the application effectiveness of deep-hole controlled pre-splitting blasting technology, it was found through laboratory micro test and field study on a mine in south China that under the technology, coal masses produce many irreversible cracks. After blasting, the nearer the distance from blasting hole, the larger the BET surface area and volume ratio of the infiltration pore are; they increased by 11.47% and 5.73%, respectively. The coefficient of air permeability is increased 4 times. After 3 months, the gas drainage rate was increased by 66%. In the first 15 days, the cumulative pumped gas was 1.93 times of blasting before. The average absolute gas emission decreased by 63.46%. Experimental results show that deep-hole controlled pre-splitting blasting not only prevents coal and gas outburst, but also gives good economic results. Supported by Project from National Natural Science Foundation of China(50674111); the National key Technology R&D Program in 10th Five Years Plan of China     

不同应力组合条件下煤岩渗透率的试验

利用自制含瓦斯煤热流固耦合三轴伺服渗流实验装置,对煤岩在不同轴压、围压和瓦斯压力组合下进行渗流试验,研究不同围压和瓦斯压力组合下的全应力-应变及在不同应力组合下煤岩渗透性的影响规律。结果表明：煤岩的渗透率随体积应力变化有三个阶段;在轴压和瓦斯压力一定的条件下,渗透率随着围压的增加而减小,且与围压呈二次曲线关系,围压对渗透率的影响比轴压大;在轴压和围压一定的条件下,渗透率随着瓦斯压力的增加先减小后增大,且与瓦斯压力呈三次曲线关系,渗透率减小阶段滑脱效应占主导地位;在一定瓦斯压力和相同体积应力下,渗透率随轴压的增加而增大,随围压的增加而减小,而且呈线性规律。     

Coal damage mechanism in the developing process of coal and gas outburst

Based on the damage analysis of elliptical aperture, the mechanism of coal damage in the developing process of coal and gas outburst was researched. The results show that the damage to coal by gas is mainly caused by the concentrated tensile stress appearing near the endpoint of the pores. Fractures in coal, gas pressure, ground stress and the tensile strength of the coal matrix are the major controlling factors of this kind of damage. When the ground stress releases abruptly and the gas pressure is high, tensile failure will occur around the endpoint of the small pores due to gas pressure, and the coal may be broken up like powder; this is called pulverization. Otherwise, when the gas pressure is low, the tensile stress can only occur around the endpoint of the large pores and fractures due to gas pressure, the fractures in coal extend and link together, the fracture extension direction is statistically perpendicular to the direction of the minor principal stress. This kind of damage is shown as the stratified spall around the outburst hole. Supported by the National Basic Research Program (973) of China (2005CB221503); the Key Project of Natural Science Foundation of China (50534080)     

Theory and test research on permeability of coal and rock body influenced by mining

Stress distribution rules and deformation and failure properties of coal and rock bodies influenced by mining were analyzed. Experimental research on permeability of coal and rock samples under different loading conditions was finished in the laboratory. In-situ measurement of coal permeability influenced by actual mining was done as well. Theory analysis show that permeability varied with damage development of coal and rock under stress, and the influence of fissure on permeability was greatest. Laboratory results show that under different loading conditions permeability was different and it varied with stress, which indicated that permeability was directly related to the loading process. In-situ tests showed that permeability is related to abutment stress to some degree. The above results may be referenced to gas prevention and drainage. Supported by the National Major Fundamental Research Program of China (973 Project) (2005CB221503); National Science Foundation of China (50544010)     

Experimental study on creep mechanics characteristics of gassy under disturbance conditions

Creep mechanics characteristics of large scale tectonic coal was studied under gas draingae and disturbance conditions by using the new self-developed coal gas coupling three axial creep equipment. The results show that when σ ₁ is smaller, σ ₃ is larger, gas pressure and disturbance load are smaller, gassy coal has no disturbance to creep. When σ ₃ is smaller, gas pressure and σ ₁ are larger, disturbance load is constant, gassy coal has remarkable effects of disturbance to creep. The concepts of disturbance load sensitive domain and disturbance creep sensitive domain were put forward. Under same amplitude disturbance stress condition, blasting disturbance has a stronger influence on gassy coal deformation is related to frequency of disturbance load; gas drainage, blasting excavation and mining play an important role in coal-gas outbursting. The relationship of gassy coal creep and gas pressure gradient, the creep constitutive equation built with gas pressure gradient and disturbance load as independent variables within the framework of fluid-solid two phases coupling were established. Supported by the National Natural Science Foundation (50474029); the China Natural Science Foundation(50534080); the Innovative Research Group(50221402); the Anhui University of Science &Technology Doctor’s Fund Project(11142)     

旋转射流提高煤层瓦斯抽排效果的试验

介绍了旋转射流扩孔技术的基本原理、设备、工艺以及现场的试验情况。通过扩大钻孔直径,达到增加钻孔的煤层暴露面积和卸压范围,增加钻孔的抽排瓦斯量,提高钻孔的抽排效果。旋转射流扩孔为提高低透气性煤层的瓦斯抽放效果和扩大防突起措施的效果提供了一个可行的技术途径。     

Disaster prediction of coal mine gas based on data mining

The technique of data mining was provided to predict gas disaster in view of the characteristics of coal mine gas disaster and feature knowledge based on gas disaster. The rough set theory was used to establish data mining model of gas disaster prediction, and rough set attributes relations was discussed in prediction model of gas disaster to supplement the shortages of rough intensive reduction method by using information entropy criteria. The effectiveness and practicality of data mining technology in the prediction of gas disaster is confirmed through practical application. Supported by the National Natural Science Foundation of China(70572070); the Liaoning Province Talents Fund Projects(2005219005); the Technology Key Project of Liaoning Province(2006220019)     

Study on multi-component combustible gas explosive characteristics of high gas mine

Studied on multi-component combustible gas, methane mainly, explosion characteristics of high gas mine, obtained the rules of gas explosive limit that influenced by environment temperature, pressure, concentration of oxygen, other combustible gas, coal dust, energy of fire source, and the inert gas, proposed a new method of divide gas explosive triangle partition, and gave new partition linear equations. The gas explosive triangle and its new partition has important directive significance in distinguishing if the fire area has a gas explosion when sealing or opening fire area, or fire extinguishing in sealed fire area, and judging if there will be a gas explosion or other trend while fire extinguishing with inert gas. Supported by the National Natural Science Fund of China(50474010); the National “Eleventh Five-year Plan” Science and Technology Support Plan of China(2006BAK03B0503); the Fund of Education Department Liaoning Province(05L-174); the Fund of Education Department Liaoning Province (20060389)     

滑脱效应影响的低渗储层煤层气运移解析分析

采用理论分析方法建立了滑脱效应影响的低渗透储层煤层气运移的数学模型，得到了有限长煤层气体稳态流动的采场压力分布解析式；无限长煤层和球向坐标煤层气体瞬态流动的采场压力分布解析式和相应的产量预测公式。通过具体矿区实例分析了抽采过程中低渗透储层滑脱效应影响的采场压力变化规律和气体产量预测规律。     

力热耦合作用下煤岩吸附及渗透特性的试验研究

利用等温吸附试验仪器与含瓦斯煤热-流-固耦合三轴伺服渗流装置,为模拟深部煤层瓦斯开采过程,分别进行不同温度下等温吸附试验与孔隙压力升高的渗流试验,建立考虑过剩吸附量修正的吸附模型并修正吸附膨胀模型,探究力热耦合作用下煤岩吸附与渗流变化规律。结果表明:瓦斯吸附量在不同温度下随瓦斯压力升高均呈增大趋势,随温度升高吸附量逐渐降低。在高压下需考虑过剩吸附量造成的误差,修正的Langmuir模型比原模型计算结果精度更高;建立了考虑温度与过剩吸附量修正的吸附变形模型与吸附膨胀模型,煤岩吸附应变随孔隙压力升高而减小,且温度越高应变变化量越小。随孔隙压力升高,煤岩渗透率及吸附膨胀与滑脱效应导致的渗透率变化量均呈下降的趋势,且随温度升高3者逐渐增加;吸附膨胀是引起煤岩渗透率减小的主要因素,吸附膨胀与滑脱效应对渗透率的贡献率随孔隙压力升高逐渐下降,其贡献率均随温度升高逐渐增加。     

赵固二矿本煤层定向长钻孔水力压裂增透技术研究

为了提高井下低透气性煤层瓦斯抽采钻孔瓦斯抽采效果,开发了适合中等偏硬低透煤层裸眼钻孔高压稳定封孔装备,采用了本煤层定向长钻孔整体水力压裂增透技术,分析了本煤层定向长钻孔水力压裂增透机理,并进行了水力压裂强化增透试验。根据压裂施工过程中压裂参数变化规律,利用压裂前后煤层全水分和钻孔瓦斯参数变化对比,综合考察和评价了水力压裂增透效果和影响范围。研究表明：压裂过程中最大注水压力24.6MPa,发生多次明显压降,最大压降5.2MPa。水力压裂增透后,煤层瓦斯日抽采纯量提高了12.70倍,百米钻孔瓦斯抽采量提高了2.67倍,压裂最大影响半径达到了 38m,平均超过30m,提高了瓦斯抽采效率。     

Matter-elements model and application for prediction of coal and gas outburst

The theory and method of extenics were applied to establish classical field matter elements and segment field matter elements for coal and gas outburst. A matter-element model for prediction was established based on five matter-elements, which included gas pressure, types of coal damage, coal rigidity, initial speed of methane diffusion and in-situ stress. Each index weight was given fairly and quickly through the improved analytic hierarchy process, which need not carry on consistency checks, so accuracy of assessment can be improved. Supported by the National Natural Science Foundation of China (50534080); the Science and Technology Research Project of Chongqing (CSCT, 2006AA7002)     

含水率对含瓦斯煤的渗流特性影响试验研究

利用自主研发的三轴煤岩瓦斯渗流试验系统,测定煤样在含水率、围压和瓦斯压力的不同组合情况下的渗流量,得到含水率与含瓦斯煤渗透特性之间的关系表达式,揭示了受水分影响的含瓦斯煤渗透特性的一些新的认识：① 不同含水率煤样,固定瓦斯压力条件下,含瓦斯煤渗透率随围压的增大而减小,且呈指数函数关系;② 不同含水率条件下的含瓦斯煤,随着瓦斯压力的增大,含瓦斯煤渗透率的先减小后增大,呈现出“V”字型变化趋势,具有明显的Klinkenberg效应;③ 瓦斯压力对含瓦斯煤渗透性的影响大于围压的影响;④ 恒定温度环境条件下,含水率对含瓦斯煤的渗透性有很明显的影响,随着煤样中含水率的增加,含瓦斯煤的渗透率逐渐减小,整体呈负指数关系。     

应力路径对煤岩渗透率影响实验研究

依据煤岩体在巷道开挖后应力出现重分布特征,利用CGMS煤层瓦斯气液相对渗透率测试系统,对屯留煤矿煤样施加不同应力组合以研究三轴加载条件下渗透率与应力、温度之间的耦合关系。实验结果表明,渗透率随应力、温度的增加而减小,各个方向的应力对渗透率的影响程度不同,且差别较大;与应力相比,温度对渗透率的影响相对较小。得出了渗透率与三轴应力和温度之间的关系,并对温度和应力对渗透率的影响进行了理论分析。     

CO2驱替煤层CH4中混合气体渗流规律的研究

CO2驱替开采煤层气过程中,由于CO2和CH4的竞争吸附,CO2/CH4混合气体在运移时CH4体积分数会不断发生改变,进而影响煤体变形和渗透特性。利用自主研发的三轴渗流系统,采用稳态渗流法对焦煤样进行单一组分气体(He,CH4和CO2)和不同配比的CH4/CO2混合气渗流试验。渗流过程中保持温度和体积应力(30 ℃、33 MPa)恒定,并利用LVDT测量煤体的轴向变形。结果表明:① He和不同配比CH4/CO2混合气的渗流过程均受滑脱效应的影响,气体渗透率随入口压力增大呈先减小后缓慢增大的变化;对于非吸附He,入口压力Symbol|@@2 MPa时滑脱效应对气测渗透率的影响要远远大于有效应力效应;② 在一定的体积应力条件下,不同配比CH4/CO2混合气体吸附引起的煤体膨胀应变随入口压力增加而增大,变化规律符合Langmiur方程,且在相同入口压力条件下,混合气体中CO2浓度越高,煤体膨胀应变越大;③ 在考虑有效应力效应、吸附膨胀应变对渗透率的动态影响以及滑脱因子b随煤体渗透率变化的基础上,建立了煤体气测渗透率理论模型,该模型能够描述不同配比CH4/CO2混合气体以及He渗透率随入口压力的变化;④ 随着煤储层CH4/CO2混合气体压力增大或者CO2体积分数升高,基质膨胀应变对煤体渗透率的影响逐渐减小。煤体中靠近孔裂隙的基质吸附膨胀对渗透率的影响(β)随入口压力的增加逐渐减小;CH4/CO2混合气体中CO2体积分数越高,β减小速率越大。     

Pattern recognition prediction of coal and gas outburst hazard in the sixth mine of Hebi

Based on the systematical analysis influence factors of coal and gas outburst, the main factors and their magnitude was determined by the corresponding methods. With the research region divided into finite predicting units, the internal relation between the factors and the hazard of coal and gas outburst, that was combination model of influence factors, was ascertained through multi-factor pattern recognition method. On the basis of contrastive analysis the pattern of coal and gas outburst between prediction region and mined region, the hazard of every predication unit was determined. The mining area was then divided into coal and gas outburst dangerous area, threaten area and safe area respectively according to the hazard of every predication unit. Accordingly the hazard of mining area is assessed. Supported by the Project of China National “973” Program(2005CB221501); National Natural Science Foundation of China(50474010); Key Laboratory Science Research Project of Liaoning Education Bureau (20060372)     

两种典型受载含瓦斯煤样渗透特性的对比

利用自主研发的含瓦斯煤岩三轴压缩实验系统,进行了受载含瓦斯煤的渗透特性实验,对比分析了受载含瓦斯型煤与原煤两种典型煤样的渗透特性之间的异同。研究结果表明,控制煤体渗透率大小的直接原因是有效孔隙度而非总孔隙度,有效孔隙度大,则渗透率大。在恒定瓦斯压力条件下,型煤与原煤的渗透率随围压的增大而减小,均服从负指数函数变化规律;相同实验条件下,型煤渗透率普遍远大于原煤渗透率,且型煤渗透率随围压下降的速度比原煤的快。在恒定围压条件下,型煤与原煤的渗透率呈现先减小后增加的趋势,在瓦斯压力p<1.0 MPa范围内均具有明显的Klinkenberg效应。全应力-应变条件下,瓦斯渗流规律与煤样的破坏形式相关,煤样渗透率都表现出先减小后增大的现象,并且具有一般的“V”字型变化规律。