A simplified conceptual model for estimating roof bolting requirements

Summary The selection of rock bolting lengths and spacings for a mine roof or back is relatively straightforward when wedges of rock bound by discrete discontinuities require support, or when the immediate roof can be anchored into a recognizably stable layer or rock mass. When neither of these situations is present the choice of bolt lengths and spacings is more difficult.In this paper a simplified conceptual model is presented which invokes the concept of an ellipticallyshaped zone of loosening above the opening, all, or a portion of which, may require support. The analysis includes the influence of opening span, height,in situ stress state, and rock mass quality as measured by the CSIR Rock Mass Classification.Validation of the model was sought by analysing a number of case histories in the literature.     

Productivity optimisation in weak sedimentary formations for improved coal production and roof stability—an approach

Far-field peak particle velocity (PPV) measurements were made in the roof while blasting in coal development drivages at Tandsi Mine, Western Coalfields Limited, India. The roof was fragile at this mine and was posing constant support problems for mining, resulting in low productivity. The PPV measurements have been used to decipher the damage zone in the roof. The extent of damage obtained has been compared to establish the threshold limits for the damage zone. Conversely, the maximum charge per delay that can be exploded is calculated and a suitable blast design has been recommended for maintaining the roof stability and pull. A roof vibration predictor equation has been developed that shows a consistent trend indicating that it may have future use in a similar geo-mining setup. The blast pattern recommended has reduced the damage extent, though marginally, but helped in improving pull. Critical PPV for incipient rock damage in underground coal mine development drivages under fragile roof were computed. The PPV level for incipient crack growth was found to vary from 500 to 800 mm/s while for overbreak it varied from 800 to 1200 mm/s. It was also observed that the location of cut holes, charge concentration and firing sequence were found to be responsible for the difference in their damage potential.     

滑动屋盖摩擦控制系统对地震频谱和结构刚度的鲁棒性

地震功率谱密度函数的频率范围和结构刚度变化对滑动屋盖摩擦控制系统减震效果的影响分析表明 :控制系统减震效果对地震功率谱的频域宽窄不敏感 ,而对功率谱所覆盖的结构自振频率敏感 ;结构刚度发生± 15 %的变化对减震效果的影响不大。分析还表明 ,滑动屋盖摩擦控制系统对于结构非线性地震反应有显著的减震作用     

屋盖MR智能隔震系统对升船结构顶部厂房地震鞭梢效应的模糊控制

基于抑制升船结构顶部厂房地震鞭梢效应的目的，本文提出了升船结构顶部厂房屋盖MR智能隔震模糊控制的思想。文中，在建立屋盖智能隔震升船结构计算力学模型的基础上，建立了屋盖MR智能隔震系统对升船结构顶部厂房地震反应模糊控制的设计计算方法。文中并以中国某大坝巨型升船结构为背景，设计了屋盖MR智能隔震系统对升船结构顶部厂房地震反应模糊控制的控制系统。仿真分析和对MR阻尼器的参数研究表明，安装合适的屋盖MR智能隔震系统并采用模糊控制策略能有效地抑制具有不确定参数升船结构顶部厂房地震反应的鞭梢效应，且模糊控制器能保持较好的稳定性能。     

煤层顶板工程地质分类方案初步研究

通过调查研究,提出了煤层顶板工程地质分类方案,此方案简单易行,验证可靠,适用于煤田勘探阶段。      

三维地震神经网络反演在探明煤层富水灾害层的应用

在常规测井约束反演的的基础上,开展神经网络特征参数反演,将波阻抗等地震属性转化为与含水性更为密切的孔隙度、视电阻率数据体,使地震反演的地质属性与测井上的地质属性达到最优的相关性,从而实现应用三维地震对煤层顶板富水进行评价的目的。由于煤层顶板富水区的特殊性质,它同样也是地震后的易破坏层,因而对它的探明从抗震角度以及震害预测角度都是有价值的。以淮北某采区为例,通过孔隙度及电阻率的神经网络反演对研究区10#煤层顶板的富水性进行预测。反演结果表明采区北部发育一个强富水陷落柱,与钻孔揭示结果吻合。采区西部10#煤层顶板与第四系含水层呈不整合接触关系,神经网络反演结果预测为强富水区,同样与井下工程揭示富水特征吻合。利用多属性融合的神经网络反演可有效预测煤层顶板的富水特征,为煤矿安全生产以及抗震提供重要保障。     

A note on estimating urban roof runoff with a forest evaporation model

A model developed for estimating the evaporation of rainfall intercepted by forest canopies is applied to estimate measurements of the average runoff from the roofs of six houses made in a previous study of hydrological processes in an urban environment. The model is applied using values of the mean rates of wet canopy evaporation and rainfall derived previously for forests and an estimate of the roof storage capacity derived from the data collected in the previous study. Although the model prediction is sensitive to the value of storage capacity, close correlation between the modelled and measured runoff indicates that the model captures the essential processes. It is concluded that the process of evaporation from an urban roof is sufficiently similar to that from a forest canopy for forest evaporation models to be used to give a useful estimate of urban roof runoff. Copyright © 2007 John Wiley & Sons, Ltd.     

利用井径资料预测鱼卡煤田东部勘探区七煤顶板的稳定性

在煤田测井中，井径的变化对其它测井参数是一种干扰，但利用井径的相对变化值（井径扩大系数），可有效地评估岩石的强度等级和可采煤层顶底板的稳定性。统计鱼卡煤田东部勘探区29个钻孔孔径的变化值，按岩石抗压强度划分原则，将其七煤顶板稳定性划分为5个等级，据此固定了该煤田七煤顶板稳定性分布图。     

昆明人民胜利堂结构抗震改造设计研究

昆明人民胜利堂为钢筋混凝土、砖砌体及木结构混合而成的结构型式，其抗震改造设计较为复杂。简述了该结构抗震改造设计施工中的若干问题，以及解决这些问题所采取的相应措施。     

模糊综合评判在煤层顶板稳定性评价中的应用

通过对淮南煤田潘三矿的顶板条件进行分析和研究,提出了一套行之有效的评价指标体系,运用模糊综合评判方法对煤层顶板稳定性进行定量评价和预测,结果表明潘三矿煤层顶板稳定性中等,北部比南部稳定性差,东部比西部差,这可以为采煤工作面顶板安全管理提供科学依据。