无料钟炉顶布料的探讨

无料钟炉顶布料是现代高炉发展趋势,合理的布料矩阵是关键,合理布料矩阵的确定依靠对碰撞点的测定,炉料堆尖对煤气流的影响以及高炉所处的外部环境等因素来确定.     

基于Matlab优化工具箱的煤巷顶板锚杆支护结构可靠性分析

针对煤巷围岩力学参数中有许多为随机变量的特征,根据围岩稳定性极限状态方程,应用工程结构可靠性理论,分析煤巷顶板锚杆支护结构的可靠性,建立基于Matlab优化工具箱的可靠度计算模型。该法编程简单,计算速度快,精度高,程序通用性强,是一种计算煤巷锚杆支护结构可靠度的有效方法,并且分析该法计算结构可靠度的适用条件,建立了巷道顶板支护参数与可靠度的关系曲线,为煤巷锚杆支护参数设计和优化提供了科学依据。     

爬山虎在高陡边坡绿化中的应用

为了解决喷混植生绿化法在边坡绿化中存在的造价高、易退化等问题,在对爬山虎习性研究的基础上,探讨了采用爬山虎绿化高陡边坡的可行性,并将爬山虎绿化法与喷混植生绿化法进行比较,得出爬山虎绿化法具有造价低、施工方便、维护简单和对环境要求不高等特点,有效地克服了喷混植生绿化法存在的缺陷.     

大连石灰石矿矿坑边坡绿化植物种类选择

大连石灰石矿矿坑边坡绿化生态修复工程主要采用厚层基材喷附和液力喷播两种工艺,喷播植物种类的选择将直接影响其生态修复效果。以该工程为例,根据工程区地理及环境特征,基于边坡绿化的基本原则,因地制宜地提出了适宜的边坡绿化植物。     

屋顶绿化二氧化碳减排效益的研究

屋顶绿化不仅能够美化城市环境,而且对城市二氧化碳减排具有一定作用。文章利用自行设计的熏气装置对几种常见屋顶绿化植物进行CO2熏气实验,测定其对CO2的吸收速率和影响因素;实验结果表明,红叶石楠、红继木和石榴等绿化植物对CO2具有显著的吸收能力,其中红叶石楠的吸收速率最高,达7.058 L/(m.2d),绿化植物对CO2的吸收速率受屋面温度影响较大,温度超过34℃时吸收速率快速减小;在实验观测基础上,结合武汉城市区域气候特征、建筑物荷载能力、屋顶绿化可用面积等信息,分析得到武汉市进行规模化屋顶绿化之后,每年可吸收转化CO21.696×106t,相当于一个194 MW火力发电厂一年的CO2排放量,屋顶绿化的发展前景较可观。     

面向21世纪城市绿化发展的思路与对策——以上海为例

本文以上海为例,探讨了生态平衡、生态位配置、互惠共生和物种多样性等生态学原理在绿地生态建设中的理论和实际应用意义,并从城市绿地指标确定、合理规划布局、丰富植物材料、城市自然公园建设及立体绿化等方面分析讨论了面向２１世纪我国城市绿化发展的思路与对策。     

煤油气共生矿井瓦斯含量主控因素分析及工作面瓦斯治理

针对崔家沟煤矿煤油气共生、瓦斯含量分布复杂、瓦斯涌出不均的特点,在分析瓦斯含量影响因素的基础上,采用灰熵关联分析法确定影响瓦斯含量的主控因素,通过顶板岩层含油强度研究2303工作面瓦斯含量分布规律,提出2303工作面瓦斯治理方案并进行应用。结果表明:顶板岩层含油强度与瓦斯含量的灰熵关联度最大为0.993 3,是影响崔家沟煤矿4-2号煤层瓦斯含量的主控因素;根据顶板含油强度可将2303工作面划分为2个瓦斯含量分布单元;采取高位钻孔与顶板走向长钻孔相结合的工作面瓦斯治理方案可有效降低高瓦斯含量分布单元回采时回风流中的瓦斯浓度,能有效确保工作面的安全高效回采。     

Seismic risk assessment of liquid overtopping in a steel storage tank equipped with a single deck floating roof

Major earthquakes have demonstrated that Natech events can be triggered by liquid overtopping in liquid storage tanks equipped with floating roofs. Thus, research on the dynamic behaviour of steel storage tanks with floating roofs is still required. In this paper, the seismic risk against liquid overtopping in a real steel storage tank with a floating roof was analysed using a simplified model that was validated by a refined finite element model based on the arbitrary Lagrangian-Eulerian approach. The simplified model utilizes the Lagrangian of a floating roof-fluid system and is capable of providing a response history of the floating roof. It was demonstrated that it could predict the maximum vertical displacement very accurately, while some differences were observed in the response history of vertical displacement. The computational time for a single response history analysis based on the simplified model amounted to a few minutes, which is significantly less demanding compared to hours required for response history analysis in the case of the refined FE model. The simplified model is thus appropriate for the seismic fragility analysis considering the overtopping limit state. It is shown that the fragility curves are significantly affected by the liquid filling level. The risk for liquid overtopping is quite high in the case of a full tank. However, by considering the variation of filling level during the year, the overtopping risk was observed reduced by approximately 30%. Alternatively, the approximate fragility analysis for the liquid overtopping can be performed by utilizing the Eurocode formula for the vertical displacement of liquid. This approach is straightforward, but the formula does not account for the higher mode effects, which may result in overestimated seismic intensity causing overtopping, as discussed in the paper.     

深部采场进路开采顶板稳定性分析与支护设计

为降低深部矿体开采中冒顶事故的发生概率,确保井下安全开采,采用Q系统分级法、RMR岩体分类和BQ分级法对矿区岩体进行质量评价,结合块体理论和三维有限元分析进路开挖后顶板的稳定性。研究表明:部分岩体在进路开挖后顶板处出现较大拉应力集中,抗拉稳定性降低,极有可能出现冒顶事故。针对这类不稳定岩体,提出永久巷道采用锚喷支护,临时巷道采用锚杆穿带支护;并运用悬吊理论、组合梁理论、屈服强度理论和安全系数法分析支护条件下进路顶板的稳定性,优化支护结构参数。通过振弦式锚杆应力计收集现场未支护巷道与支护巷道轴向力,得出该支护设计对开挖后岩体变形起到了明显改善作用。     

音频电透视法在防治矿井水患中的应用

为了探明某矿20910工作面顶板0~100 m上高部区域岩层富水性分布情况,基于音频电透视法,通过在工作面回风巷、运输巷布置了59个发射点,104个接收点,获得了工作面顶板0~50 m、50~100 m高度范围音频电透视成果图。探测结果表明,20910工作面顶板0~100 m存在4处低阻异常区域,实际回采揭露发现涌水点5处,均位于探测低阻异常区域,探测结果与实际揭露结果验证很吻合。实践表明,该矿20910工作面顶板0~100 m音频电透视法探测成果合理可靠,音频电透视法可以准确探测出工作面顶板一定范围内相对富水区域分布情况。