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More and more multiple-track tunnels and super-large section tunnels have been built, and disman- tling of temporary strut is a weak point of the whole structure during force transfer when the secondary lining is con- structed. It is significant to guarantee structure safety during dismantling of temporary strut. Little systematic re- search on safety in dismantling of temporary strut of the super-large section tunnel with double-layer primary support has been conducted, so the internal force and security of the two-layer primary support of the Xinkaotang tunnel were analyzed by a numerical analysis and site measurement, and it proves the effect of two-layer primary support on the safety during strut dismantling. The research results indicate that: (1) with constant support thickness and one-time longitudinal dismantling length, the safety factor of secondary primary support is larger than that of the first primary support, and the safety factor of the first primary support is larger than that of the single-layer primary support. Change range of safety factor for the first primary support is smaller than that of the single-layer primary support, and the safe factor for the single-layer primary support is smaller than that of the secondary primary support; (2) with the same support pattern, the safety factors increase firstly and then decrease with an increase of the onetime dismantling length. The calculated results of various cases show that the reasonable one-time dismantling length for this project is about 9 m. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献
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介绍了节能轴支架的作用机理、设计方法和叶剖面的优化。节能轴支架的作用机理与桨前固定导轮相似 ,但设计要比桨前固定导轮简化 ,并要兼顾轴支架自身的作用和要求。文中详细给出了轴支架的布置形式和在船模试验中获得的显著节能效果。试验结果证明把轴支架的两支臂设计成有约 1 0°的收缩角可增大节能轴支架的预旋作用 ,从而增大节能效果 ,使轴支架的节能效果达约 1 2 %。空泡试验和激振力测量结果表明 ,把Eppler的翼型势流设计方法设计翼型与解 N-S方程进行流场分析相结合 ,用层流型高升阻比翼型优化节能轴支架是成功的 ,能有效地降低轴支架的阻力和推迟空泡初生 ,从而有利于节能轴支架在高速船上推广应用。实船安装证明本文的设计方法是成功的 相似文献
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高升阻比翼型优化及其节能轴支架设计 总被引:1,自引:1,他引:0
用Eppler的叶剖面设计方法与解N-S方程相结合的方法进行水翼剖面的优化,并给出了将其应用到螺旋桨节能轴支架设计中获得的显著节能效果的试验结果,空泡试验结果也证明了这种设计方法是成功的。节能轴支架的设计思想还被推广应用到单桨船上,开发出了扇形预旋导管。 相似文献
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针对实体式混凝土桥墩开裂现象,采用有限元方法与撑杆一系杆理论分析裂缝成因。分析结果表明,开裂是由于设计方法不当,钢筋配置数量不足所致。本文还进一步讨论了桥墩的加固方法,建议采用体外预应力加固方案。 相似文献
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减振柱作为摩托车减震器重要零件之一,在表面电镀前的磨削质量控制尤为关键。通过设定合理的工艺、调整磨床、磨料及相关辅料的管理控制,使减振柱镀前磨削加工质量有了稳定提高。减振柱镀前精磨表面粗糙度控制在Ra0.15以内,一次合格率获得提高;部分配套出口高档车型的减振柱在精磨环节配置UB砂轮后,外观质量表面粗糙度Ra≤0.10;将粗磨、精磨两类磨削时的机床用连线机构连接、选择合适的磨削液等,提升了磨削加工效率与质量。 相似文献
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在“双碳”战略背景下提出一种新型装配式空心钢管混凝土支撑。为了研究其受力性能并将其应用于地下车站深基坑工程中,设计并加工2个足尺寸空心钢管混凝土支撑试件,完成轴压加载试验,2个支撑试件最后均发生了混凝土压碎破坏,同时得到试件承载力指标。采用ABAQUS有限元软件建立空心钢管混凝土支撑的数值模型,开展考虑材料非线性和几何非线性的有限元分析,所得数值分析结果与试验结果吻合良好,验证了有限元模型的准确性。试验和有限元结果充分表明所提出的新型装配式空心钢管混凝土支撑满足常规工程设计要求,已成功应用于“汤马区间”2号风井工程,并与现浇钢筋混凝土支撑和装配式钢管支撑进行比较分析,结果表明该新型支撑可以显著降低碳排放量和经济成本。 相似文献