共查询到19条相似文献,搜索用时 78 毫秒
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对大体积混凝土裂缝控制,从设计、材料、施工、测温、养护等方面进行讨论,并提出在施工大体积混凝土时常采用的方法. 相似文献
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针对高层建筑底板大体积混凝土裂缝的原因和控制要求,从底板大体积混凝土结构裂缝控制的设计措施、材料措施和施工措施等方面进行阐述。 相似文献
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裂缝控制技术在防辐射大体积混凝土中的应用 总被引:1,自引:0,他引:1
水泥在水化过程中产生大量的热量,使混凝土内部温度升高。当混凝土内部与表面的温差过大时,就会产生温度应力,当这种温度应力超过混凝士内外的约束力时,就会产生裂缝,影响混凝土的正常使用,本文介绍了几种控制裂缝的方法。 相似文献
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以某电厂冷却水排水尾部建筑工程施工为实例,介绍应用大体积混凝土温度裂缝理论指导施工,以及施工质量控制措施。 相似文献
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阐述了大体积混凝土裂缝控制的设计和施工技术。在施工过程中通过采取改善设计构造、约束程度、温升控制、延缓降温速率、减少混凝土收缩和提高混凝土极限拉伸等方面措施,综合控制,取得了良好的效果。 相似文献
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针对大体积混凝土基础底板裂缝问题的预防和控制是多年来一直在攻关的技术难题。结合实际,介绍筏板大体积混凝土裂缝要点及为控制因温差导致的大体积混凝土基础底板裂缝所提出的有效的应对措施。 相似文献
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为了解决区段煤柱内沿空布置瓦斯通排巷时合理确定留设煤柱尺寸的问题,以白芨沟煤矿布置010203工作面瓦斯通排巷为工程背景,通过采用理论计算、现场实测与数值模拟相结合的方法,对区段煤柱应力分布特征展开研究。结果表明:引用内应力场理论求得区段煤柱侧内应力场宽度为8.35m;基于现场实测结果分析得出内应力场分布范围约距采空区0-7m;运用FLAC3D软件对留设不同窄煤柱尺寸下区段煤柱内应力分布、巷道围岩变形特征展开深度研究,得出区段煤柱内合理窄煤柱尺寸的确定方法;最终结合该矿实际情况确定窄煤柱留设合理尺寸为5m。 相似文献
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本文从“管理、培训、装备并重”的安全管理原则出发 ,强调了在职工素质和现有装备条件不能出现根本性改变的前提下 ,就必须突出抓管理的安全管理观念 ,并从事故预想控制、作业过程控制、重点环节控制、思想动态控制、全员联保控制 5个方面说明了王庄煤矿实施全过程控制的安全管理方法和效果 相似文献
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混凝土强度的尺寸效应评述 总被引:1,自引:0,他引:1
强度的尺寸效应问题是混凝土科学的主要问题之一.论文分析了混凝土材料产生强度尺寸效应的原因,并介绍了目前混凝土学界分析尺寸效应的三种理论方法,同时加以比较和分析,最后对混凝土强度尺寸效应分析的数值方法作了简要介绍. 相似文献
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《Minerals Engineering》2006,19(6-8):531-538
Design and operating conditions of large size mechanical flotation cells were evaluated by comparing it with the actual operating conditions in a plant. The objective was to determine the time scale-up factor, typically based on empirical rules. Experiments were conducted on the rougher flotation circuit at Minera Escondida Ltd. The circuit consisted of self-aerated mechanical cells of 160 m3, arranged in six parallel banks with nine cells each.The rougher circuit flotation kinetics was evaluated from direct sampling and local mass balances around each cell of the bank. Adjusted overall mass balances were also developed. This information was used to fit different kinetic flotation models, and it was found that the rectangular distribution function was the most appropriate to describe the distributed rate constant for industrial operation. Then, a rougher flotation simulator was developed to describe the actual operation in terms of the operating variables (mass flow rate, solid percentage, feed grade) and the actual volumetric flow rate entering to each cell. In this study feed pulp samples were taken in parallel from the rougher circuit and were simultaneously floated in laboratory. The kinetic behavior was then modeled at a laboratory batch scale in order to determine the time scale-up factor between laboratory batch flotation data and industrial size flotation. The time scale-up factor observed for large sized cells, 160 m3, was found reasonably similar to those previously determined for self-aerated mechanical cells, but of lower size, operating at similar recoveries. In addition, the relative effect of mixing, between laboratory batch and an industrial flotation bank was quantified by the ϕ parameter, separating the impact that kinetic and mixing changes have on the time scale-up factor.In general, the rougher flotation operation was found to reach the predicted metallurgical target, and that the optimal separability criterion was also respected.The diagnostic generates information about the internal state of the process and helps to identify potential improvements for design, operation and control of the circuit. 相似文献
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浅谈高层建筑大体积混凝土施工 总被引:4,自引:0,他引:4
高层大体积混凝土施工过程中存在相当普遍的主要问题是裂缝,文章介绍了合理控制混凝土配合比,选用良好的级配骨料,改善施工工艺,采取有效的养护方法等综合技术措施进行裂缝控制,经实践应用效果良好. 相似文献