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1.
浅谈门式刚架轻型钢结构厂房中抗风柱的设置 总被引:1,自引:0,他引:1
通过对抗风柱上下端的节点几种形式进行分析比较,提出建议性的节点连续方式。 相似文献
2.
通过对曼型气柜关键部位之一的基柱的安装和找正过程的分析,表明基柱安装前对基础进行预处理、安装时测量跟踪找正、安装后定位加固,是保证基柱安装精度的三个重要步骤。 相似文献
3.
垂直平行密集束状孔落矿有底柱崩落法是一种新的采矿方法。通过爆破模型试验,测试爆破应力,观察分析爆破效果,探求最佳布孔形式,选择最优爆破孔网参数。试验结果表明:用平行束状孔取代扇形落矿,改善了爆破效果,简化了采场结构,减少了采切工程量。 相似文献
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以局部表面改性的紫铜直方柱和梯度方柱阵列为研究对象,实验研究了表面润湿性、表面形貌和表面活性剂对池沸腾换热性能和气泡生长特性的影响。实验工质为去离子水,浓度分别为100、200、400、800 mg·L-1的异丙醇溶液和正庚醇溶液。实验结果表明:方柱阵列表面镀银之后润湿性变差,表面产生的气泡数量减少。向去离子水中添加异丙醇或正庚醇后,在热通量为66.1~202 kW·m-2时,气泡脱离直径变小、数目减少,而当热通量增至413 kW·m-2时,活性剂能够有效阻碍气泡合并,故池沸腾传热系数随着浓度增加先减小后增大。上下层宽分别0.5 mm和1 mm、间距为2 mm的梯度方柱阵列结构有助于气泡的合并,但由于促进了固体表面气膜的形成,从而降低了沸腾换热性能。 相似文献
6.
《矿业科学技术学报(英文版)》2017,27(2):261-267
In some of the coalfields in India, coal seams are only developed but no extraction of pillars is possible due to the presence of surface or sub-surface structures and also non-availability of stowing materials which leads to huge amounts of coal being locked-up underground. Spontaneous heating and fire, accumulation of poisonous gases, severe stability issues leading to unsafe workings and environmental hazards are the major problems associated with the developed coal pillars. So, there is a pressing need for a technology for the mining industry to extract the huge amount of coal locked-up under different constraints. In this study, the locked-up coal is proposed to be extracted by artificially strengthening the rib pillars. The detailed comparative study is carried out to know the increase of extraction percentage of locked-up coal by strengthening the rib pillars with FRP. Extraction methodology is designed and studied through numerical modelling for its stability analysis to evaluate its suitability of application in underground. 相似文献
7.
针对综采面"采场-邻空煤柱-采空区"间的漏风微循环现象,利用MATLAB中的PDE工具进行二维非线性渗流的数值模拟,同时分析研究漏风微循环现象形成的原因,以及漏风微循环对煤炭自燃的影响。研究表明,"采场-邻空煤柱-采空区"间的漏风微循环可以导致采空区内相对压力和气体成分的周期性变化,即"采空区喘息"现象。 相似文献
8.
Controlled calcination of Texas montmorillonite has allowed production of a range of materials of cation exchange capacity from 70 mequiv./100 g dry clay to virtually zero. Pillaring of these with Chlorhydrol precursor solution has then provided a family of materials of pillar density ranging from about one per six unit cells to zero. The analytical technique based on isomorphous metal dilution (IMD) that follows pillaring is validated. The results provide a consistent value for the precursor (Keggin) ion charge, in the conditions normally used, of 3.15±0.10 rather than the formal value of 7. An approach to the attainment of pillar densities consistent with the introduction of shape/size selectivity on pillared layered materials is outlined. 相似文献
9.
《矿业科学技术学报(英文版)》2014,24(5):597-601
This paper analyzed the deformation mechanism in lateral roof roadway of the Ding Wu-3 roadway which was disturbed by repeated mining of close coal seams Wu-8 and Wu-10 in Pingdingshan No. 1 Mine. To determine the strata disturbance scope, the strata displacement angle was used to calculate the protection pillar width. A numerical model was built considering the field geological conditions. In simulation, the mining stress borderline was defined as the contour where the induced stress is 1.5 times of the original stress. Simulation results show the mining stress borderline of the lateral roadway extended 91.7 m outward after repeated mining. Then the original stress increased, deforming the roadway of interest. This deformation agreed with the in situ observations. Moreover, the strata displacement angle changed due to repeated mining. Therefore, reselection of the displacement angle was required to design the protective pillar width. Since a constant strata displacement angle was used in traditional design, the proposed method was beneficial in field cases. 相似文献
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