采场动压分布特征及高效瓦斯抽放技术研究

河南地区大部分煤矿所采煤层均属于三软煤层，煤层透气性差，瓦斯治理困难。现阶段河南区域煤与瓦斯突出矿井主要采用穿层钻孔及开采保护层作为区域防突措施，而低瓦斯矿井或临突矿井（低瓦斯矿井与煤与瓦斯突出矿井相邻）存在高瓦斯区时，仅仅用风排瓦斯很难达到治理效果，近些年煤矿发生瓦斯事故多数为低瓦斯矿井，所以低瓦斯矿井和临突矿井存在高瓦斯区域的工作面回采期间瓦斯治理尤为重要。根据采场“竖三带”和“横三区”理论，利用钻孔抽放效果考察法和工作突出预测指标法研究了采场围岩动压分布特征。在此基础上，通过优化动压区抽放钻孔设计，提高了瓦斯抽放效果。瓦斯抽放量提高了1.8倍，有效降低了工作面生产期间的风排瓦斯量，提高了生产效率，保证了矿井安全生产。     

A finite line source simulation model for geothermal systems with series- and parallel-connected boreholes and independent fluid loops

A model for the simulation of geothermal systems with parallel- and series-connected boreholes is presented. Mass and heat balance problems are formulated for each component in the system and are assembled into system-level problems. A third problem is formulated to account for heat transfer in the bore field, using the finite line source solution. This third problem is coupled to the system-level heat balance problem by an analytical solution of the heat transfer inside boreholes with multiple U-tubes. The simulation model allows for any number of independent fluid loops within the bore field or within individual boreholes and allows for combinations of specified inlet fluid temperatures and heat extraction rates in independent fluid loops. The model accounts for the axial variation of the fluid and borehole wall temperatures and heat extraction rates. The capabilities of the model are demonstrated through three example simulations.     

A practical data-flow verification scheme for business processes

Data in business processes becomes more and more important. Current standard languages for process modeling like BPMN 2.0 which include the data flow reflect this. Ensuring the correctness of the data flow in processes is challenging. Model checking, i.e., verifying properties of process models, is a well-known technique to this end. An important part of model checking is the construction of the state space of the model. However, state-space explosion typically is in the way of an effective verification. We study how to overcome this problem in our context by means of reduction. More specifically, we propose a reduction on the level of the process model. To our knowledge, this is new for the data-flow analysis of processes. The core of our approach are so-called regions of the process model that are relevant for the verification of properties describing the data flow. Non-relevant regions are candidates for reduction of the process model, yielding a smaller state space. Our evaluation shows that our approach works well on industrial process models.     

基于多因素耦合分析的冲击地压卸压技术研究

为有效预防ZF2803工作面的冲击地压,本文采用多因素耦合分析法研究了初次来压、见方、煤柱、断层、邻近空区支承压力、煤层厚度变化及巷道底煤等7个因素的单独影响区域及叠加效果,确定了7个危险区:中等冲击危险区4个、强冲击危险区3个,给出了相应的煤层及底板大钻孔预卸压措施,工业性应用取得了良好的防治效果。     

综放工作面上隅角瓦斯治理技术实践

为解决瓦斯矿井综放面推采过高瓦斯区域时,上隅角瓦斯易超限的问题,结合赵庄二号井2309工作面地质情况,研究实施了工作面采空区瓦斯抽采和上隅角软管抽放的综合治理技术。实践表明:在2309综放工作面回采期间,上隅角瓦斯浓度得到有效控制,平均为0.15%,最高为0.36%,为工作面安全生产提供了有力保障。     

Viscosity of glass-forming melt at the bottom of high-level waste melter-feed cold caps: Effects of temperature and incorporation of solid components

During the final stages of conversion of melter feed (glass batch) to molten glass, the glass-forming melt becomes a continuous liquid phase that encapsulates dissolving solid particles and gas bubbles that produce primary foam at the bottom of the cold cap (the reacting melter feed in an electric glass-melting furnace). The glass-forming melt viscosity plays a dominant role in primary foam formation, stability, and eventual collapse, thus affecting the rate of melting (the glass production rate per cold-cap area). We have traced the glass-forming melt viscosity during the final stages of feed-to-glass conversion as it changes in response to changing temperature and composition (resulting from dissolving solid particles). For this study, we used high-level waste melter feeds—taking advantage of the large amount of data available to us—and a variety of experimental techniques (feed expansion test, evolved gas analysis, thermogravimetric analyzer-differential scanning calorimetry, X-ray diffraction, and viscometer). Starting with a relatively low value at the moment when the melt connects, melt viscosity reached maximum within the primary foam layer and then decreased to its final melter operating temperature value. At the cold-cap bottom—the boundary between the primary foam layer and the thermal boundary layer—where physicochemical reactions of a melter feed influence the driving force of the heat transfer from the melt to the cold cap, the melt viscosity affects the rate of melting predominantly through its effect on the temperature at which primary foam is collapsing.     

Three-dimensional thermal analysis of the repository for high-level radioactive nuclear waste

One of the key issues of the dimensioning design and safety assessment of the repository for deposing the high-level radioactive nuclear waste is the temperature distribution. A three-dimensional layered model was established for analyzing the heat conduction near single waste canister. Applying the Laplace transform and finite Fourier Sine transform upon the governing equations of heat conduction, the solutions in the Laplace domain were obtained. The solutions in the Laplace domain were numerically inverted into semi-analytical solutions in the time domain by the Crump method, and the temperature distribution was obtained near the canister at the center of one disposal panel. The initially estimated value of the canister spacing was determined according to the temperature distribution and design criterion. Finally, the obtained temperature distribution was used to investigate the influence of relevant parameters on the canister surface temperature. The results show that the present model is reliable by comparing with the existing analytical model. The peak canister surface temperature is significantly affected by the tunnel spacing, canister spacing, thickness of buffer layer, and thermal conductivities of buffer material and surrounding rock.     

THE DISTANCE BETWEEN BOREHOLES OF SMOOTH BLASTING BY WATER COUPLING

The stress strength factor, length and opening degree of cracks around boreholes as well as movement regularity of blockage with the smooth blasting by water coupling are calculated out according to the theories of fracture mechanics and explosion dynamics, and the relation between the pressure in holes and the change of hole volume is pointed out, thereby the distance between boreholes is worked out in this paper. For limestone, when uncoupling coefficient is 3,diameter of holes is 100 mm, the hole distance of water coupling smooth blasting is 2.3 m. The result is consistent with practice.     

地面采空区瓦斯抽放钻孔稳定性分析

以淮南矿区地面钻孔抽放试验为基础,运用现场考察数据分析和数值模拟相结合的研究方法,分析了地面钻孔的稳定性,得出了和以往不同的认识。认为钻孔的破坏是随着工作面推进而发生的动态过程,布置在靠近回风巷侧钻孔更加稳定。     

浅孔注水技术改革成功应用浅析

通过浅孔注水技术改进,达到了降低煤尘、预防煤与瓦斯突出、减小回风流瓦斯浓度、减小冲击地压、降温、增加煤体韧性的作用和效果,保证了"双突"工作面的回采安全。