浅煤层采空区层面漏风的数值模拟分析

结合大柳塔煤矿活鸡兔井21208工作面开采实例，按采空区层面漏风情况，将采空区顶板岩层冒落划分为自由冒落带、顶板断裂带和地表沙土层带。建立了层面漏风的定解数学模型，将地表漏风强度近似看作按负指数规律衰减。通过用有限元方法求解漏风移动渗流方程，得到采空区冒落带所形成的压力腔与地面之间的压力差形成的采空区层面漏风，漏风强度沿工作面长度方向变化不大，层面漏风强度主要取决于顶板断裂带的尺寸和地表沙土层带的厚度与密实性。     

重塑矿山工业景观规划实验(之二)——兖矿集团兴隆庄煤矿采空区重建规划设计研究

我国能源结构以煤炭为主的格局短期内不会改变.煤炭生产造成地表塌陷的采空区日益扩大,极大地消耗着我国形势本已严峻的土地资源.一般来说,采空区的利用就是土地复垦、养鱼、绿化等.该文研究采取一定技术措施,利用煤矸石填筑采煤塌陷区作为建筑用地,造基建房,不仅可减少煤矸石污染、占地问题,同时解决采空区内村庄的就地安置难题,变采空区为居住用地,村民不用搬迁.一举多得,为解决兖州矿区的可持续发展、重建矿区生态环境提供了一条重要的技术途径.     

侧翼推进在地下转露天矿采空区处理中的应用

针对地采转露采过程中出现的高危空区,在崩落法无法安全实施的情况下,采用束装孔侧翼推进的方式处理采空区,达到安全、可靠的目的。以1310空区为例,详细介绍了束装孔控制爆破的实施过程,为复杂空区处理提供了一条新的思路,对今后空区处理工作具有较高的参考价值。     

Bulking factor of the strata overlying the gob and a three-dimensional numerical simulation of the air leakage flow field

The present study examines the results of the researches related to the gob bulking factor carried out at home and abroad. A mathematical function of a three-dimensional gob bulking factor is described based on a three-dimensional gob model. The method of taking value for interstice and permeability ratios is also proposed. The law of air leakage of fully mechanized top coal is researched in this study. The results show that the speed of air flow near the upper and lower crossheadings is higher than that in the central section of the gob at the same distance from the working face. When the amount of air at the working face exceeds a critical amount, the width of the spontaneous combustion zone in the upper and lower crossheadings is also larger than that in the central section. In this situation, the key is preventing the coal left in the upper and lower crossheadings from self-igniting. Reducing the amount of air at the working face can decrease the width of the spontaneous combustion zone, especially the width near the upper and lower crossheadings. This also moves the spontaneous combustion zone in the direction of the working face. It can prevent the coal in the gob from self-igniting by making the coal left in the crossheadings to be inert and by effectively controlling the amount of air at the working face.     

Method of calculation of a methane concentration field in gob areas with a known velocity field based on the model of stream tubes

The control equations of gas concentration field in gob areas with a known velocity field are partial differential equations with variable coefficients, whose traditional mathematical calculation methods are very complex. A numerical simulation method can be used to calculate the gas concentration field, but it also needs considerable amounts of computer resources and the relations of gas concentration at different points of the gob area are undefined. Based on the model of stream tubes, the conservation equations of mass and gas components within the stream tube are used to deduce the equations of a gas concentration field in a gob area with a known velocity field. This method of calculation of a gas concentration field is applied in a gob area with a U-type ventilation working face, which suggests that this new method has the virtue of exact calculations is simple to operate and has a clear physical interpretation.     

回采工作面瓦斯涌出规律研究

某矿2781回采工作面经常发生瓦斯浓度超限现象，为掌握该工作面瓦斯涌出规律和确保工作面安全生产，笔者对该工作面瓦斯涌出量进行了实测，对工作面瓦斯涌出来源及构成进行了分析，并利用回归分析法，找出了工作面落煤、煤壁瓦斯涌出规律，获得了采空区瓦斯浓度分布规律，为工作面的通风管理与安全生产提供了必要的技术指导。     

鹿台山矿沿空留巷围岩变形规律分析及补强支护设计

为缓解鹿台山煤矿矿井采掘接续紧张的状况,同时减少相邻工作面区段巷道掘进工程量,降低掘进工程费用,确保2203工作面顺利接替,对2202工作面轨道顺槽进行沿空留巷试验。根据巷道围岩地质条件,通过理论分析,并结合切顶卸压预裂爆破顶板技术,提出了切顶卸压沿空留巷支护方案。通过连续观测工作面回采期间的巷道围岩变形特征,总结了切顶卸压沿空留巷的矿压显现规律。分析结果对于鹿台山矿沿空留巷实践有一定的参考价值。     

Unanticipated multiple seam stresses from pillar systems behaving as pseudo gob–case histories

Underground coal mining in the U.S. is conducted in numerous regions where previous workings exist above and/or below an actively mined seam. Miners know that overlying or underlying fully extracted coal areas, also known as gob regions, can result in abutment stresses that affect the active mining. If there was no full extraction, and the past mining consists entirely of intact pillars, the stresses on the active seam are usually minimal. However, experience has shown that in some situations there has been sufficient yielding in overlying or underlying pillar systems to cause stress transfer to the adjoining larger pillars or barriers, which in turn, transfer significant stresses onto the workings of the active seam. In other words, the overlying or underlying pillar system behaves as a ‘‘pseudo gob." The presence of a pseudo gob is often unexpected, and the consequences can be severe. This paper presents several case histories, summarized briefly below, that illustrate pseudo gob phenomenon:(1) pillar rib degradation at a West Virginia mine at 335 m depth that contributed to a rib roll fatality,(2) pillar rib deterioration at a Western Kentucky mine at 175 m depth that required pillar size adjustment and installation of supplemental bolting,(3) roof deterioration at an eastern Kentucky mine at 400 m depth that stopped mine advance and required redirecting the section development,(4) coal burst on development at an eastern Kentucky mine at 520 m depth that had no nearby pillar recovery, and(5) coal burst on development at a West Virginia mine at the relatively shallow depth of 335 m that also had no nearby pillar recovery. The paper provides guidance so that when an operation encounters a potential pseudo gob stress interaction the hazard can be mitigated based on an understanding of the mechanism encountered.     

无煤柱综采工作面沿空留巷支护技术应用

为了保证8201无煤柱综采工作面安全高效回采，提高沿空留巷顶板稳定性，防止沿空巷顶板出现破碎、冒落现象，通过技术研究，合理分析了8201无煤柱综采工作面在回采期间主要存在的技术难题，并对沿空巷（5201巷）顶板提出了预裂爆破切顶卸压技术，并采取了“柔模浇筑+迈步式走向JW型锚索吊棚+桁架锚索支护”联合支护技术，通过实际应用效果来看，切顶卸压技术有效阻止工作面回采应力向沿空巷侧传递，防止了沿空巷顶板下沉、破碎现象；与传统挡矸装置相比，联合支护技术成本费用低、施工工序简单，有效起到了挡矸护顶作用，而且有效防止了工作面回采时超前集中应力对沿空巷破坏作用，超前应力区顶板下沉量控制在0.15 m以下。     

Criterion of local energy release rate of gob instability in deep mines considering unloading stress path

The stress path characteristics of surrounding rock in the formation of gob were analyzed and the unloading was solved. Taking Chengchao Iron Mine as the engineering background, the model for analyzing the instability of deep gob was established based on the mechanism of stress relief in deep mining.The energy evolution law was analyzed by introducing the local energy release rate index(LERR), and the energy criterion of the instability of surrounding rock was established based on the cusp catastrophe theory. The results show that the evolution equation of the local energy release of the surrounding rock is a quartic function with one unknown and the release rate increases gradually during the mining process.The calculation results show that the gob is stable. The LERR per unit volume of the bottom structure is relatively smaller which means that the stability is better. The LERR distribution showed that there was main energy release in the horizontal direction and energy concentration in the vertical direction which meets the characteristics of deep mining. In summary, this model could effectively calculate the stability of surrounding rock in the formation of gob. The LERR could reflect the dynamic process of energy release,transfer and dissipation and that provided an important reference for the study of the stability of deep mined out area.