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291.
矿山岩体工程的系统工程 总被引:2,自引:1,他引:2
用系统工程学的观点, 重新认识矿山岩体工程的特点。建立矿山岩体工程稳定性的系统的概念。提出地质模型、设计模型、施工模型的构思, 使工程地质、设计、施工三者密切结合, 共同解决矿山岩体工程稳定问题。通过动态监测和信息反馈, 在工程施工的动态过程中不断地获得新的认识, 以便对工程实施做出新的决策。 相似文献
292.
以建筑抗震设计规范GBJ11-9(条文说明)中涉及到的新疆地区考虑远震影响的城镇为研究对象,采用现行的地震危险性分析概率方法,考虑远震和近震影响的实质,提出了一处合理的确定远震和近震影响的方法,进而确定这些城镇的基本烈度是远震影响还是近震影响。 相似文献
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Prior to this study, no simplified yet rational methods were available for estimating the vertical displacements of energy pile groups subjected to thermal loads. Observing such a challenge, the goal of this study has been threefold: (i) to extend the interaction factor concept from the framework of conventional pile groups to that of energy pile groups, (ii) to present charts for the analysis of the displacement interaction between two identical energy piles over a broad range of design conditions, and (iii) to propose, apply and validate the interaction factor method for the displacement analysis of energy pile groups. 相似文献
296.
论述了水雾灭火的特点,应用范围。以及国内外在船舶消防方面的应用现状。针对我国实际情况,提出了船舶水雾灭火设计的一般要求,对具体设计基本参数,水力计算,系统的监测与控制等进行了探讨,并用计算实例进行验证。 相似文献
297.
The use of historical bathymetric charts in a GIS to assess morphological change in estuaries 总被引:3,自引:0,他引:3
Navigational charts are a valuable data source for the study of morphological change in estuaries, as they provide bathymetric information of many estuaries, and span a vast period of time. Charts are suitable for studying patterns of morphological change, such as shoal and channel migration. In addition, sequential bathymetric charts or bed surveys can be used to calculate sedimentation and erosion rates. However, a number of problems arise when using these data to identify morphological change. Sources of error and uncertainty are associated with surveying techniques used, density of depth sampling points, interpolation and averaging during compilation of the chart. Large systematic errors may stem from the non-uniformity or poorly defined levels to which the depths on the charts are reduced. Errors propagate in spatiotemporal operations using such charts. Analysis of historical bathymetric charts from the Ribble estuary (north-west England) illustrates the difficulties involved in assessing morphological change in a quantitative manner. The pattern of morphological development within the Ribble estuary over the last 150 years was clear, and a significant long-term net accretional trend was found. However, temporal variations in the rate of sedimentation on a decadal scale were generally not significant. 相似文献
298.
砂土液化对设计反应谱和场地分类的影响 总被引:5,自引:0,他引:5
本文采用有效应力原理分析了液化土层对设计反应谱的影响,分析中考虑了砂层的厚度、埋深和输入地震动等因素。选择Ⅱ类场地,将其标准反应谱合成的三条地震加速度时程在考虑土层非液化下反演到基岩,再正演计算存在液化层时的地面运动时程和反应谱。分析结果表明,从特征周期的变化来看,液化土层使Ⅱ类场地易变为Ⅳ类场地,对地震影响系数的作用则不是很大,但频谱上0.8s是一个分界线,液化土层对分界线以下的高频分量有一定减震效果,对分界线以上的低频分量有显著的放大效应。 相似文献
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The paper presents a theoretical and an experimental investigation into the plastic collapse of circular steel corrugated cylinders under external hydrostatic pressure. The experimental investigation gives a detailed study of 9 steel corrugated cylinders which were tested to destruction. Six of these cylinders failed by plastic non-symmetric bifurcation buckling and three failed by plastic axisymmetric deformation. The results of these tests were used, together with the results obtained from previous tests, to present a design chart for the plastic collapse of these vessels. The design chart was obtained by a semi-empirical approach, where the thinness ratios of the vessels were plotted against their plastic knockdown factors. The process of using the design chart is to calculate the theoretical elastic instability pressure for a perfect vessel by the finite element method and also to calculate the thinness ratio for this vessel. Using the appropriate value of the thinness ratio, the plastic knockdown factors are obtained from the design chart. To obtain the actual collapse pressure of the vessel, the theoretical elastic instability pressure for a perfect vessel is divided by the plastic knockdown factor. This work is of importance in ocean engineering. A large safety factor must also be introduced. 相似文献