Block medium breaking with a grouped explosion

Results are presented for experimental studies of breaking artificial block media by simultaneous explosion of two and four cylindrical charges. Regularities are established for the change in granulometric composition and size of average lump for broken material depending on the distance to charges in the characteristic directions of failure zones. Institute of Geophysics, Ukrainian National Academy of Sciences, Kiev. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 84–92, July–August, 1999.     

Material permeability in the elastic strain zone of a camouflet explosion

Geological Exploration Institute, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 91–96, September–October, 1989.     

Evaluation of the 2-D permeability tensor for fractured rock masses

An approach is established to evaluate the 2-D permeability tensor of naturally fractured rock masses by using modified UDEC 5. Based on the superposition principle, directional flow-rates through a unit square of fractured rock under head gradients in two orthogonal directions can be calculated with UDEC. Then the flow-rates are transformed into flow-rates through a field rock mass for evaluating the permeability tensor. Two kinds of fractured rock models, fixed hydraulic fracture aperture and variable hydraulic fracture aperture under stress, were studied by using this approach. For the first model, the permeability tensor of a fractured rock mass only depends upon the statistical features of fracture pattern geometry, including orientation, trace length, density of fractures. For the second model, the permeability tensor strongly depends upon both the geometry of the fracture pattern and the applied stress, such as the direction and magnitude of principal stress as well as the ratio of major principal stress to minor principal stress.     

高瓦斯低透气性煤层深孔预裂爆破增透数值模拟

针对高瓦斯低透气性煤层,采用Taylor方法建立了一个新的LS-DYNA3D爆破损伤模型,对深孔预裂爆破进行了数值模拟研究,再现了爆破过程中,动压冲击震裂、应力波传播与叠加以及爆生气体驱动裂纹扩展的整个过程,分析了爆破孔间距对爆生裂纹和爆破增透效果的影响,提出了高瓦斯低透气性煤层深孔预裂爆破的合理间距为5~6 m,为高瓦斯低透气性煤层的瓦斯抽放提出了解决方案.     

Evolution of stresses and permeability of fractured-and-porous rock mass around a production well

The authors model deformation and mass transfer in jointed and porous rock mass around a production well. The modeling based on the concept of a continuum with double porosity uses an original method with finite difference solution of mass transfer equations and analytical solution of pore elastoplasticity equations. From the numerical experiments, dimensions of irreversible deformation zones in the well bore zone grow with the parameter Bio. The estimate of the reservoir permeability decline in the course of operation, obtained from the pore elasticity and pore plasticity models, qualitatively agrees with the in situ observation data.     

水力冲孔钻孔周围煤层透气性变化规律

为了研究水力冲孔钻孔周围煤层透气性变化及分布规律,基于煤层实际赋存条件,采用压力法和含量法对水力冲孔卸压范围进行了现场试验考察。采用RFPA2D-Flow软件模拟分析了水力冲孔钻孔周围煤体应力及透气性变化规律。结果表明：受水力冲孔的影响,孔洞周围形成了半径为5.0~6.0 m的卸压范围,卸压范围内应力在0.038~6.545 MPa之间,在距被考察孔6.8 m处,出现应力集中现象,最大主应力为15.85 MPa,与现场考察结果基本一致。孔洞周围煤层透气性的分布规律与主应力变化趋势相一致。距卸压区域距离不同,煤体最大主应力不同,越靠近孔洞的区域,应力和瓦斯压力下降幅度越大,煤层透气性系数也就越大。     

Numerical simulation and experiment analysis of improving permeability by deep-hole presplitting explosion in high gassy and low permeability coal seam

Created a new damage model for explosive for LS-DYNA3D, taking advantage of the Taylor method aimed at the high gassy and low permeability coal seam, and numerically simulated and analyzed the deep-hole presplitting explosion. The entire process of explosion was represented, including cracks caused by dynamic pressure, transmission and vibration superposition of stress waves, as well as cracks growth driven by gas generated by explosion. The influence of the cracks generated in the process of explosion and the performance of improving permeability caused by the difference of interval between explosive holes were analyzed. A reasonable interval between explosive holes of deep-hole presplitting explosions in high gassy and low permeability coal seams was proposed, and the resolution of gas drainage in high gassy and low permeability coal seam was put forward. Supported by the National Science Foundation of China (50534090, 2007BAK28B01, 2007BAK29B06); the Science Foundation of Anhui Province (050440403); Creative Team Plan for High School of Anhui (2006KJ005TD)     

Energetic estimate of the action of a contact explosion

Moscow Engineering Physics Institute. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 57–60, July–August, 1989.     

如何保证矿用隔爆设备的隔爆性能

文章分析了影响矿用隔爆设备隔爆性能的几方面因素,介绍了防止矿用隔爆设备失爆的几个措施。     

Modeling the explosion of a system of borehole charges in a scarp

Conclusions On the basis of the mathematical model here proposed for the action of the explosion of two cylindrical (borehole) explosive charges in the scarp of a rock mass, the scope for investigating the correlation between wave propagation parameters with scarp rock cutting in a pit is expanded. This offers the possibility of solving a series of problem associated with the correction of wave propagation parameters and their optimization in conditions of open-pit mining of minerals. Mining Institute, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 33–38, March–April, 1986.     

Model of the effects of an explosion in a well

Conclusions A new model of explosions in wells was proposed on the basis of the "inverse" (in terms of the factor of rock pressure) zonal disintegration of rocks around underground workings (Discovery No. 400) and the anomalously low friction in block media detected experimentally by the authors in an investigation of pendulum-type waves. Considerable weight was given to the empirical finding that for certain energies of shock loading of models of block media, friction "vanishes" between interacting blocks of geologic materials in directions orthogonal to the line of action of the external impulse. The geometric parameters of the quasi-cylindrical system of blocks formed around an exploded well are determined by the scale factor of the zonal disintegration process, this factor being linked to the radius of the well; the dynamic—kinematic characteristics of geologic blocks capable of moving along the annular "inverse" disintegration zones are determined by the type of stress state of the surrounding rock masses. Institute of Mining, Siberian Branch of the Russian Academy of Sciences, Novosibirsk. Translated from Fiziko—Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 37–46, March–April, 1997.     

岩溶陷落柱周边裂隙带岩体渗透性的试验研究

以皖北刘桥矿区岩溶陷落柱为例，通过全应力-应变渗透试验，研究受采掘影响的不同应力场条件下柱边裂隙围岩渗透性的变化规律以及动水压力与岩体变形的关系，为陷落柱渗流场和应力场的耦合分析提供参数。     

Calculation of the Stresses around a Crack

An algorithm for solution of the three-dimensional problem of the stress state of an unbounded elastic medium that imitates a rock mass with a crack is discussed. The crack is represented by a large number of dislocation loops, the stress field in the vicinity of which is described by Peach and Koehler contour integrals. Calculations produced by means of the developed program are compared to the analytic solution.     

瓦斯爆炸诱导沉积煤尘参与爆炸作用模式

应用连续相、颗粒相计算方法对瓦斯爆炸诱导沉积煤尘参与爆炸的传播过程进行数值模拟,并以此对爆炸作用模式及其异同进行研究。根据模拟结果,从不同煤尘云点火机理在爆炸过程中所起主导作用将爆炸模式分别确定为沉积煤尘扬尘爆炸和沉积煤尘火焰燃烧。进一步分析表明：不同爆炸作用模式显著改变冲击波和火焰传播规律,影响小规模诱导火焰区的长度...     

Development of an explosion during the formation of a collapse dam

O. Yu. Shmidt Institute of Earth Physics, Academy of Sciences of the USSR, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 56–59, March–April, 1991.     

由屯兰矿瓦斯爆炸事故引发的思考

该文以屯兰煤矿瓦斯爆炸事故为切入点,指出了我国现阶段煤矿安全生产中存在的问题,主要有煤矿安全监管责任不到位,煤矿安全主体责任落实不到位,煤矿技术管理和现场管理不到位。