非均质煤层瓦斯分布特征及钻孔抽采瓦斯运移规律研究

为了提高煤矿瓦斯抽采率，节约瓦斯抽采时间，分析了非均质煤层瓦斯分布特征及钻孔抽采瓦斯运移规律，采用透气性系数研究了非均质煤层瓦斯压力分布特点；分析了非均质煤层单钻孔瓦斯压力分布、原始瓦斯压力、原始透气性系数对有效抽采半径的影响。研究对指导现场瓦斯抽采以及促进煤矿安全生产具有重要意义。     

Influences of flow rate and baffle spacing on hydraulic characteristics of a novel baffle dropshaft

Due to limited flow capacity and the instability of the asymmetric structure of traditional baffle dropshafts, a novel baffle dropshaft with a symmetric structure, adopting the construction shield well directly, is proposed for large-range flow discharge in deep tunnel drainage systems. In this study, a two-phase flow field of the novel baffle dropshaft with three different baffle spacings was simulated at seven different flow rates with a three-dimensional (3D) numerical model verified with experiments, to study hydraulic characteristics of this novel baffle dropshaft. The results show that the novel baffle dropshaft has a remarkable energy dissipation effect. Baffle spacing of the novel baffle dropshaft has a greater effect on flow patterns and baffle pressure distributions than the comprehensive energy dissipation rate. Flow rate is a critical issue for the selection of baffle spacing in the design. Some guidance on baffle spacing selection and structure optimization for the application of this novel baffle dropshaft in deep tunnel drainage systems is proposed.     

Soft sensing of water depth in combined sewers using LSTM neural networks with missing observations

Information and communication technologies combined with in-situ sensors are increasingly being used in the management of urban drainage systems. The large amount of data collected in these systems can be used to train a data-driven soft sensor, which can supplement the physical sensor. Artificial Neural Networks have long been used for time series forecasting given their ability to recognize patterns in the data. Long Short-Term Memory (LSTM) neural networks are equipped with memory gates to help them learn time dependencies in a data series and have been proven to outperform other type of networks in predicting water levels in urban drainage systems. When used for soft sensing, neural networks typically receive antecedent observations as input, as these are good predictors of the current value. However, the antecedent observations may be missing due to transmission errors or deemed anomalous due to errors that are not easily explained. This study quantifies and compares the predictive accuracy of LSTM networks in scenarios of limited or missing antecedent observations. We applied these scenarios to an 11-month observation series from a combined sewer overflow chamber in Copenhagen, Denmark. We observed that i) LSTM predictions generally displayed large variability across training runs, which may be reduced by improving the selection of hyperparameters (non-trainable parameters); ii) when the most recent observations were known, adding information on the past did not improve the prediction accuracy; iii) when gaps were introduced in the antecedent water depth observations, LSTM networks were capable of compensating for the missing information with the other available input features (time of the day and rainfall intensity); iv) LSTM networks trained without antecedent water depth observations yielded larger prediction errors, but still comparable with other scenarios and captured both dry and wet weather behaviors. Therefore, we concluded that LSTM neural network may be trained to act as soft sensors in urban drainage systems even when observations from the physical sensors are missing.     

对高层民用建筑消防给排水设计中几个疑难问题的探讨

根据实践经验,总结出若干高层民用建筑消防给排水设计疑难问题,值得提出探讨和交流,以便引起广大审核人员特别是初学者的注意,防止类似的错误发生。     

谈国内外排水沥青路面的应用发展现状

介绍了排水沥青路面的特点,重点阐述了排水路面在国内外的发展现状,同时总结了其中存在的问题,并提出了解决的建议,以期有效提高路面质量,满足公路相关技术要求。     

防排水施工技术在隧道施工中的应用分析

隧道工程设计遵循“防、排、截堵相结合，因地制，宜综合治理”的原则，以达到隧道工程防排水施工质量可靠的目的。本文结合广州新客站地区市政道路及相关附属工程，简单介绍了防排水施工技术在隧道施工中的应用。     

GIS技术在城市防洪排涝中的应用分析

随着城镇化进程不断加快以及气候变暖带来的极端气候变化,部分城市接连遭受大型洪涝灾害。暴雨洪涝在引起媒体与公众普遍关注的同时,也给城市管理部门的防御和对策研究带来了新的难题。GIS技术在空间信息分析上的广泛应用为城市应对汛期洪涝灾害提供了新方法和新思路。     

云盖山煤矿一矿综放工作面瓦斯综合治理技术研究

针对云盖山煤矿一矿煤层透气性系数低、煤层预抽效果差、瓦斯制约生产能力的现状,提出了以本煤层顺层钻孔瓦斯抽放为主,以上隅角瓦斯抽放为辅的瓦斯综合治理技术,减轻了风排瓦斯的压力,实现了高产高效,创造了良好的经济效益和社会效益。     

Remediation of acid mine drainage using metallurgical slags

In this study basic oxygen and stainless steel slag were both assessed for potential use in treating acid mine drainage. The stainless steel slag was able to effect some pH change but was found to not be suitable. Basic oxygen slag was found to have a significant potential as a remediating agent. For a model acid mine water with a pH of 2.5, sulfate concentration of 5000 mg/L and iron concentration of 1000 mg/L, the slag was able to increase pH to 12.1, reduce the soluble iron by 99.7% and reduce sulfate by 75% in batch experiments. In these batch reactors most reaction was completed within 30 min indicating that this is a rapid process. Additional experiments were conducted with continuous flow reactors to assess the maximum treatment capacity of the slag. These experiments indicated that slag replacement strategies are wholly dependent on the strength of the acid mine drainage, the required residence time and the specified residual concentrations of iron or sulfate and the pH. The data indicate that in particular, basic oxygen furnace slag has significant potential as a replacement reagent for lime in treating acid mine drainage.