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结合港珠澳大桥珠澳口岸人工岛西北护岸水泥搅拌桩施工,简述水泥搅拌桩施工质量控制要点和方法。水泥搅拌桩施工质量控制的关键为水泥搅拌机型的选择、水泥品牌的选用、水泥掺入量和每延米用量的选配、桩位、桩径和垂直度的控制、施工参数的确定。 相似文献
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为了研究钢轨磨耗和疲劳裂纹萌生寿命与钢轨硬度的关系,基于Archard磨耗模型和临界平面法疲劳裂纹萌生预测模型,结合磨耗和型面变化分段迭代和疲劳损伤累积,提出了钢轨疲劳裂纹萌生和磨耗共存预测方法;对4种不同硬度钢轨的磨耗发展、疲劳损伤累积以及疲劳裂纹萌生寿命进行研究. 结果表明:该方法预测的裂纹萌生寿命与现场观测结果有较好的吻合性;高硬度钢轨可以降低磨耗、延长疲劳裂纹萌生寿命,适合在小半径曲线上应用;4种硬度的钢轨中,钢轨硬度每提高10 HBW,平均磨耗发展率将降低约3%~6%,疲劳裂纹萌生寿命延长约9%~12%;对比U78CrV/U76CrRE热轧钢轨,U78CrV热处理钢轨的平均硬度值增加了17.9%,磨耗发展率降低了约19.8%,疲劳裂纹萌生寿命延长了约57.7%;在轮轨摩擦系数为0.3时,4种钢轨的疲劳裂纹均萌生于轨面1.0~2.5 mm以下的亚表面范围内,距离轨顶中心15~18 mm. 相似文献
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高铁的高平顺性要求在线路开通前要进行钢轨预打磨,以沪宁城际高铁为样本,通过分析钢轨打磨前状态,发现新轨上道后存在光带不在轨顶中部,甚至有两点接触等问题,借鉴欧洲铁路在研究轮轨噪声时制定的轨面粗糙度水平标准和钢轨打磨、铣磨作业标准,利用1/3倍频和各波长范围的幅值统计,对钢轨预打磨后轨面不平顺状态进行评价,结果表明钢轨预打磨能够有效改善了轨面的不平顺状态。 相似文献
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The benchmark of a simply supported beam with damage and bending fuzzy stiffness consideration is established to be utilized for damage detection. The explicit expression describing the Rotational Angle Influence Lines (RAIL) of the arbitrary section in the benchmark is presented as the nonlinear relation between the moving load and the RAIL appeared, when the moving load is located on the damage area. The damage detection method is derived based on the Difference of the RAIL Curvature (DRAIL-C) prior to and following arbitrarily section damage in a simply supported beam with bending fuzzy stiffness consideration. The results demonstrate that the damage position can be located by the DRAIL-C graph and the damage extent can be calculated by the DRAIL-C curve peak. The simply supported box girder as a one-dimensional model and the simply supported truss bridge as a three-dimensional model with the bending fuzzy stiffness are simulated for the validity of the proposed method to be verified. The measuring point position and noise intensity effects are discussed in the simply supported box girder example. This paper provides a new consideration and technique for the damage detection of a simply supported bridge with bending fuzzy stiffness consideration. 相似文献
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近年来,能源危机出现的同时人类环保意识也不断加强,追求健康、环保的汽车逐渐成为一种新趋势。21世纪是一个“绿色”的世纪,开发“绿色”汽车将成为未来我国汽车工业一大突破口。因此,本文提出发展有中国特色的“绿色”汽车新措施。 相似文献
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