无人工作面开采坚硬顶板冲击运动的3DEC数值模拟研究

分4个阶段模拟了无人工作面开采坚硬顶板采场顶板的运动规律.第1阶段,坚硬顶板的悬而不落是下一区段无煤柱开采的隐患.开采范围达到8 000 m2时的第2阶段,采场坚硬顶板的冲击性垮落,使工作面前方煤体及巷道既已形成的高应力区骤然释放.开采范围继续扩大的第3阶段和第4阶段,坚硬顶板从整体大范围冲击性运动向周期性分段运动转化.北京矿务局木城涧煤矿无人工作面坚硬顶板在采场面积约为8 000 m2的初次冲击性垮落,验证了3DEC理论研究结论,其强制放顶等防冲措施实施的最佳时机为第2阶段的开采活动结束之前.     

Release of sulfur- and oxygen-bound components from a sulfur-rich kerogen during simulated maturation by hydrous pyrolysis

An immature sulfur-rich marl from the Gessosso-solfifera Formation of the Vena del Gesso Basin (Messinian, Italy) has been subjected to hydrous pyrolysis (160 to 330°C) to simulate maturation under natural conditions. The kerogen of the unheated and heated samples was isolated and the hydrocarbons released by selective chemical degradation (Li/EtNH₂ and HI/LiAlH₄) were analysed to allow a study of the fate of sulfur- and oxygen-bound species with increasing temperature. The residues from the chemical treatments were also subjected to pyrolysis–GC to follow structural changes in the kerogens. In general, with increasing hydrous pyrolysis temperature, the amounts of sulfide- and ether-bound components in the kerogen decreased significantly. At the temperature at which the generation of expelled oil began (260°C), almost all of the bound components initially present in the unheated sample were released from the kerogen. Comparison with an earlier study of the extractable organic matter using a similar approach and the same samples provides molecular evidence that, with increasing maturation, solvent-soluble macromolecular material was initially released from the kerogen, notably as a result of thermal cleavage of weak carbon–heteroatom bonds (sulfide, ester, ether) even at temperatures as low as 220°C. This solvent-soluble macromolecular material then underwent thermal cleavage to generate hydrocarbons at higher temperatures. This early generation of bitumen may explain the presence of unusually high amounts of extractable organic matter of macromolecular nature in very immature S-rich sediments.     

Analysis of oil lens removal by extraction through a seepage face

Removal of LNAPL (oil) from an aquifer is described using a multiphase flow model. At the well boundary seepage face conditions are imposed. These conditions are implemented in a numerical model and withdrawal in a twodimensional domain is simulated for two different geometries of the oil lens and for varied values of the physical parameters. Assuming vertical equilibrium, the oil flow equation is reduced by vertical integration. The well boundary condition is approximated by imposing zero oil lens thickness. Similarity solutions of the reduced equations for the two geometries show good agreement with the numerical results in most cases.     

电测深在康定白土坎滑坡勘查中的应用

在白土坎滑坡勘察中，采用电测深来探测滑体结构、滑床形态及古拉裂其效果较好，为正确评价古滑坡的稳定性提供了较为充分的依据。     

De-bugging the 'millipede' porphyroblast microstructure: a serial thin-section study and 3-D computer animation

ABSTRACT Seventy-five spatially orientated, serial thin sections cut from a single rock containing ‘millipede’ porphyroblast microstructure from the Robertson River Metamorphics, Australia, reveal the three-dimensional (3-D) geometry of oppositely concave microfolds (OCMs) that define the microstructure. Electronic animations showing progressive serial sections of the 3-D microstructure are made available via the World Wide Web. The OCM amplitudes decrease regularly from a maximum in near-central sections to a minimum in near-marginal sections, whereas the OCM interlimb angles increase regularly from a minimum in near-central sections to a maximum in near-marginal sections. These observations illustrate that the OCMs are noncylindrical surfaces with culminations located in near-central sections. Because the porphyroblast cores appear to have been present before significant development of the syn-OCM foliation, all of the OCMs were formed by heterogeneous extension around these cores. The overall geometry of the OCMs described here reflects the strain state, and cannot be used to constrain deformation paths.     

浅变质岩石中的叠加韧性剪切带——以吉林桦甸二道甸子地区为例

吉林省桦甸市二道甸子金矿区的板岩、千枚岩中,存在着平行叠加式和垂直叠加式两个类型的韧性剪切带。它们叠加在早期变形构造之上,显示出不同的构造特征。前者以含“叶理鱼”的疙瘩状千枚岩为特征,“叶理鱼”的含量决定了其应变强度。后者以折劈构造成带状发育为特征,折劈的不同类型决定了其应变强度。     

A neural network model for liquefaction-induced horizontal ground displacement

The horizontal ground displacement generated by seismically induced liquefaction is known to produce significant damage to engineered structures. A backpropagation neural network model is developed to predict the horizontal ground displacements. A large database containing the case histories of lateral spreads observed in eight major earthquakes is used. The results of this study indicate that the neural network model serves as a reliable and simple predictive tool for the amount of horizontal ground displacement. As more data become available, the model itself can be improved to make more accurate displacement prediction for a wider range of earthquake and site conditions.     

孤岛工作面动力灾害预防控制方法研究

为研究孤岛工作面安全开采方法,理论分析其动力灾害多发的岩层运动及应力条件,并提出其安全开采的准则。认为只要合理设计开采参数,就可以避免孤岛工作面动力灾害的发生。分析表明:孤岛工作面长度大于相邻工作面支承压力影响范围之和时,孤岛工作面支承压力无法叠加,工作面较安全;相邻工作面长度大于关键层断裂步距时,覆岩关键层可充分塌垮,孤岛工作面无动压冲击危险;在稳定的内应力场开掘回采巷道时,回采巷道无冲击危险。     

网络三维数字城市海量模型优化算法研究

大规模海量三维模型数据网络传输和终端可视化是面向Web的三维GIS应用关键技术。本文提出将三维模型自适应面删除简化算法和地形模型单面片自动生成算法相结合,实现大批量构建面简化LOD （层次细节模型）模型库自动建库,有效解决了海量高精度、大范围三维模型面向Web的三维GIS应用问题。研究成果在天津市网络三维数字城市规划管理系统项目中成功进行试验,效果显著。     

定向钻井技术在垂直井中的轨迹控制分析

在重庆市区及周边乡镇开展的多口地热井钻井施工中,由于大多数取水点地层倾角过大、岩性变化频繁等原因,常规钻井方法无法保障井眼井斜角达标,从而影响获取地热水资源的成功率。采用定向钻井工具进行纠斜钻 进时,钻具工具面角与井眼方位角变化值的选择对井眼轨迹的影响尤为重要,同时当钻具工具面角确定以后,新井眼的形成还受地层岩性、钻头选型及钻井参数等各方面的影响。为了井眼轨迹更为平滑,避免形成“狗腿”井段,本文通过对某地热井中定向钻井施工案例进行分析,从实际案例中总结经验,对定向钻井井眼轨迹的可控条件进行了优化。