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Improving lateral track strength after ballast maintenance
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作者 Stephen Wilk Dingqing Li 《Railway Sciences》 2025年第2期141-158,共18页
Purpose–MxV Rail conducted multiple single tie push tests(STPTs)between 2020 and 2023 to assess the changes in lateral tie resistance from tonnage accumulation,dynamic track stabilizers(DTS),tie type and ballast cond... Purpose–MxV Rail conducted multiple single tie push tests(STPTs)between 2020 and 2023 to assess the changes in lateral tie resistance from tonnage accumulation,dynamic track stabilizers(DTS),tie type and ballast condition.High lateral tie resistance is necessary for preventing lateral misalignments and track buckles.Therefore,understanding how various factors affect the lateral tie resistance will aid in the development of track buckling risk assessments and ballast maintenance best practices.Design/methodology/approach–The test involved tamping a section of track that consisted of both concrete and wood ties and then increasing the lateral tie resistance,using either tonnage during speed restrictions or a DTS.The STPTs and top-of-rail(TOR)elevation measurements were taken at multiple stages,including immediately after tamping and then after different tonnage increments or DTS.The results from this test were then added to a compiled measurement from previous tests,and the results from all the tests were used to develop general guidelines for ballast maintenance best practices and trade-off considerations.Findings–The results showed multiple factors affect the lateral track strength and therefore the susceptibility to misalignments and track buckles.The disturbance from ballast tamping can reduce the lateral track strength by 20–80%(∼45%median)and can be compacted from either tonnage(25–50%regain in strength after 0.1 m gross ton or MGT)or DTS(33–78%regain in strength).The amount of ballast(shoulder width and crib height),tie type and ballast characteristics all have a meaningful role in lateral track strength.Originality/value–This paper is based on the testing programs conducted by authors at MxV Rail. 展开更多
关键词 Lateral track strength Single tie push test(stpt) Track buckle TAMPING Shoulder width Crib height
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中南地区几种土壤的表面电荷特性
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作者 贺纪正 刘冬碧 《华中农业大学学报》 CAS CSCD 北大核心 2000年第3期240-248,共9页
在比较几种测定土壤电荷零点方法的基础上,研究了中南地区几种土壤的正负电荷量、电荷零点(PZG)和净电荷零点(PZNC)。(1)推荐将盐滴定-电位滴 作为测定土壤PZC的常规方法,该法较电位测定(PT)法简便、消耗样品... 在比较几种测定土壤电荷零点方法的基础上,研究了中南地区几种土壤的正负电荷量、电荷零点(PZG)和净电荷零点(PZNC)。(1)推荐将盐滴定-电位滴 作为测定土壤PZC的常规方法,该法较电位测定(PT)法简便、消耗样品量较少,而比盐滴定(ST)法获取的信息量较多。(2)铁铝氧化物是土壤正电荷的主要载体,其中非晶形铁铝氧化物具有重要贡献。(3)在低PH时土壤主要带永久负电荷随PH升高。 展开更多
关键词 正负电荷量 电荷零点 净电荷零点 土壤 stpt
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一种电能质量扰动的检测和分类方法 被引量:29
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作者 文继锋 刘沛 《电力系统自动化》 EI CSCD 北大核心 2002年第1期42-44,共3页
提出了一种噪声情况下检测、定位电能质量扰动 ,同时对电能质量扰动的形式进行分类的新方法。这种方法基于 2种短窗算法 :短窗功率算法和短窗自相关算法。任何加载在电压上的扰动实际上可以视为电压的能量在这段时间发生了变化 ,短窗功... 提出了一种噪声情况下检测、定位电能质量扰动 ,同时对电能质量扰动的形式进行分类的新方法。这种方法基于 2种短窗算法 :短窗功率算法和短窗自相关算法。任何加载在电压上的扰动实际上可以视为电压的能量在这段时间发生了变化 ,短窗功率算法就是基于这个事实而提出 ,短窗自相关算法用来滤除电压功率微分中的噪声。 展开更多
关键词 电压质量扰动 短窗功率算法 短窗自相关算法 检测 分类
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