共查询到20条相似文献，搜索用时 15 毫秒
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阿拉沟枢纽工程沥青混凝土心墙大坝最大坝高超过105m,工程量大,施工难度大,且沥青混凝土心墙需要进行冬季施工,其施工质量的控制是关键,包括材料选择与配比、拌合与运输、入仓与碾压、材料试验与质量检测等多个控制环节。介绍了碾压式沥青混凝土心墙施工的一般技术要求与做法,着重描述了沥青混凝土心墙在-20℃范围内的冬季施工方法与措施,以供类似工程借鉴。 相似文献
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魏惠生 《长江工程职业技术学院学报》2006,23(3):26-29
南阳回龙抽水蓄能电站上库碾压混凝土重力坝,由于受地形等自然条件影响,入仓方式和拌和能力等受到限制,在本工程中采用了坝前入仓,且在碾压混凝土施工中采用斜层平推法施工,较好地解决了入仓和碾压混凝土施工问题,而且在碾压混凝土施工中加强了施工工艺控制,从成本和质量上都取得了很好的效果. 相似文献
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芦琴 《杨凌职业技术学院学报》2012,11(1):21-23
碾压混凝土坝由于其自身特点得到广泛的应用,我国在碾压混凝土坝筑坝技术方面也取得了喜人成果,随着相关实验研究和实践探索,碾压混凝土坝的施工技术得到持续不断的创新与完善。当前,在国家大力发展水利事业的大背景下。相信碾压混凝土坝会向更加安全、更加快速、更加经济、质量更加可靠、更加环保的高水平发展壮大。得到更多的应用。 相似文献
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Calculation Model of Equivalent Strength for Induced Crack Based on Double-K Fracture Theory and Its Optimizing Setting in RCC Arch Dam 总被引：2，自引：0，他引：2
By means of fracture testing on roller-compacted concrete (RCC) three-point bending beams with two different specimen sizes, the P-CMOD complete curve for RCC was gained. Furthermore, by applying double-K fracture theory, KIC^ini,KIC^un, as well as the critical effective crack length and the critical crack tip opening displacement, were evaluated. Based on the double-K fracture parameters above, the calculation model of equivalent strength for induced crack was established, thus the calculation method on its initiation, stable propagation and unstable fracture was ascertained. Moreover, the finite element simulation analysis of stress field in ShaPai arch dam and the on-site observational splaying points of induced crack at different altitudes validated the reliability of the model. Finally, crack inducer‘s optimal setting in RCC arch dam was studied. It improves the design level of induced crack in RCC arch dam and satisfies the necessity of engineering practice. 相似文献
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碾压混凝土坝施工工艺简单、工期短、造价低、适应性强,在坝工界得到广泛应用。虽胶凝材料少,水化热低,但由于采用大仓面通仓连续浇筑的施工方式,故碾压混凝土坝的温度裂缝不可忽略。本文通过对碾压混凝土坝温度裂缝的分析,总结了温控防裂的方法,为碾压混凝土坝的设计、施工和防裂提供参考。 相似文献
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The parameters of existing roller-compacted concrete (RCC) dam construction simulation are usually fixed based on experience while the actual construction conditions of an RCC dam change during the process of the project. The simulation accuracy of an RCC dam is therefore reduced because the change has not been considered. A new method for RCC dam construction simulations based on real-time monitoring is presented in this paper. First, real-time monitoring technology is used to collect and analyze the actual construction information. Second, meteorological data obtained from the real-time monitoring system are analyzed using the fuzzy average function method, and the weather conditions of the next stage are forecasted. Then the construction schedule simulation model is updated via the Bayesian update method. Results of the analysis are used as the input to the construction simulation parameters, and the construction simulation is performed. A real-world engineering example is presented to compare the simulation results with the actual construction schedule. The results demonstrate that the method can effectively improve the accuracy and real-time performance of construction simulations. 相似文献
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During the storehouse surface rolling construction of a core rockfilldam, the spreading thickness of dam face is an important factor that affects the construction quality of the dam storehouse' rolling surface and the overallquality of the entire dam. Currently, the method used to monitor and controlspreading thickness during the dam construction process is artificialsampling check after spreading, which makes it difficult to monitor the entire dam storehouse surface. In this paper, we present an in-depth study based on real-time monitoring and controltheory of storehouse surface rolling construction and obtain the rolling compaction thickness by analyzing the construction track of the rolling machine. Comparatively, the traditionalmethod can only analyze the rolling thickness of the dam storehouse surface after it has been compacted and cannot determine the thickness of the dam storehouse surface in realtime. To solve these problems, our system monitors the construction progress of the leveling machine and employs a real-time spreading thickness monitoring modelbased on the K-nearest neighbor algorithm. Taking the LHK core rockfilldam in Southwest China as an example, we performed real-time monitoring for the spreading thickness and conducted real-time interactive queries regarding the spreading thickness. This approach provides a new method for controlling the spreading thickness of the core rockfilldam storehouse surface. 相似文献
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轧制道次计算模型的主要任务是对粗轧机和精轧机的最优化配置进行计算,以4200mm轧机为背景,从5个轧制模型和2种轧制模式入手对PSC进行了研究和分析。 相似文献
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芦琴 《杨凌职业技术学院学报》2011,10(4):7-9
碾压混凝土坝由于其自身特点得到广泛的应用,但也存在较严重的裂缝问题。本文在碾压混凝土坝施工过程仿真计算的基础上研究了碾压混凝土坝的温控防裂措施,以期对生产实践有一定的指导意义。 相似文献
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高线轧机滚动轴承出现故障时,通过振动分析,在时域图中有明显冲击特征,自相关函数有明显的时间间隔,概率密度函数图像不是正态分布,振动趋势图中振幅均有明显上升并超过允许值的现象,峭度值一般均超过4,瀑布图中在转频处出现明显的连续性且峰值较高,均是轴承存在潜在故障表像。从轴承内圈、滚动体、保持架和外圈四个部分进行监测,轴承内圈、滚动体和外圈有五种常见损坏形式,保持架有三种常见损坏形式。由于内圈旋转频率、滚动体过内圈的频率和滚动体过外圈的频率对表面缺陷有较高的灵敏度,在监测过程中是最有效的。 相似文献
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本文对板带轧制过程中产生的头部弯曲从理论上进行了研究。结果表明简单对称轧制过程中轧件不会产生头部弯曲。对于异步轧制而言,轧制过程是轧件压缩、剪切和弯曲变形的复合变形过程,由于金属的流变状态和力学状态的不对称,全后滑产生的不均匀应力导致轧件头部易产生弯曲。 相似文献
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通过实验和理论推导对影响滚锥滚动方式的各个几何参数和力学参数,以及各参数之间相互制约的关系进行了深入的分析.应用其内在的原理解释了类似"怪坡"自动上滚现象的原因. 相似文献
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邵峰 《合肥联合大学学报》2002,12(2):102-107
轧制理论中对钢在热轧状态下变形情形的研究，通常是在一定的理论条件下进行的。本从热加工实际出发。对影响钢的热轧变形的一些因素加以探讨。 相似文献
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黄晓红 《广东轻工职业技术学院学报》2010,9(2):4-6,10
稳定张力控制是批量薄规格热轧钢板生产的关键技术。为了提高轧机张力控制质量,减少堆钢现象,建立一种带钢热轧张力控制模型,以此为基础设计一种张力控制器,改善活套控制性能,提高活套的稳定性,从而有利于大批量轧制薄规格带钢。 相似文献
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在轧钢过程中,轧辊工作条件恶劣,经常发生微量损伤,通过修磨可以消除损伤,延长轧辊的使用寿命,本文从砂轮选择、磨削参数选择、磨削过程中的冷却等几方面对轧辊的修磨进行了探讨,确定了合理的轧辊修磨方法。 相似文献
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采用有限元软件MSC．Superform对角钢热连轧过程进行有限元模拟。介绍了模拟过程中的模型建立、材料参数、边界条件以及载荷的定义,分析了轧制过程中轧件温度场的分布和变化过程,分析结果对制定角钢热连轧过程的温度制度提供了有效参考。 相似文献
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针对某厂五机架冷连轧机的一二机架间张力系统为被控对象,利用H∞控制理论设计其张力鲁棒控制器。采用Matlab7．0工具以轧机张力为对象进行仿真试验,仿真研究结果表明所设计的张力鲁棒控制器对前后滑和外界干扰等不确定性具有良好的抑制作用,从而证明了所设计控制器的有效性与实用性。 相似文献
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