大爱无言!新大洲本田助力摩托车返乡

<正>归心似箭,风雨无阻。只为了家中殷切期盼着的双亲和一餐平淡却不凡的家宴,他们义无反顾地驾上爱车,踏上了遥遥返乡路。随着两广间的高铁开通、购置汽车的门槛降低等原因,在外务工人员的出行方式丰富了不少,有些人早己不必再骑乘摩托车往来两广,但通过笔者了解,仍有部分返乡人员坚持数年,依然选择骑摩托车返乡。这个群体中有初次上路的幼雏,也有五次三番的老鸟,即便如此,爱心企业的暖流行动却不曾势弱。     

砂板岩互层隧道掌子面突水灾变发生模型试验研究

To investigate the catastrophic mechanism and pattern of water inrush in tunnels in sand-slate strata, this paper takes the Xinping Tunnel on China-Laos Railway as the study case, and through model tests, reproduces the catastrophic occurrence and evolution process of the water inrush in the progressive failure of slate aquifuge, so as to analyze the changing pattern of the stress-strain characteristics of surrounding rocks, seepage pressure and flow rate with the decreasing thickness of the aquifuge. The results show that: (1) The water inrush in the sand slate strata would experience three stages: seepage, inrush and attenuation, which is essentially a gradual evolution process where, under the action of excavation unloading and stress and seepage coupling, fractures in the weak parts of the aquifuge gradually expand and break through until inrush channels are formed and the stability of the aquifuge loses gradually; (2) The stress-strain curve of the surrounding rocks and the relationship between the seepage pressure and flow show significant precursor and stage characteristics, and their changing patterns reflect the breeding, devel⁃ opment and evolution process of the disaster; (3) A sudden change point exists in the changing process of the seep⁃ age pressure and flow rate, and this sudden change point can be seen as the characteristic point of degradation in the water-blocking capacity of the aquifuge. The aquifuge thickness reflected by this point can be seen as the critical safety thickness of the aquifuge. © 2023 Editorial By Modern Tunnelling Technology. All rights reserved.     

新型能馈式牵引供电系统短路仿真

建立新型能馈式牵引供电系统的仿真模型,分别对牵引网直流侧近端短路和远端短路、交流侧两相相间短路进行仿真,对短路时电压电流的动态特性进行分析,提出给直流侧支撑电容串电阻来限制短路冲击电流的方法,并通过仿真进行验证,为新型能馈式牵引供电系统的保护特性选择以及牵引变电站容量和参数的设计提供参考依据.     

对甘肃少数民族经济发展的若干思考

本文在分析甘肃省少数民族地区经济现状的基础上，提出了加快甘肃少数民族地区经济发展的若干建议。     

国际海运结构的变化及其特点

本文论述了国际海运业在船舶登记制度，发展中国家海运业的发展，国际船员劳务市场等方面所产生的结构变化，同时并分析了这些结构变化的原因及特点。     

EDM三角高程测量在一次性建立隧道三维控制网中的应用探讨

探讨在地貌类别单一的山区，基于图形较强的平面控制网、高程网严密平差等条件和措施，将在平面控制测量中进行的ＥＤＭ三角高程测量用于隧道高程控制，一次性建立隧道洞外三维控制网的可行性。