Loss of stability of a railway wheel-set,subcritical or supercritical

Most researches on railway vehicle stability analysis are focused on the codimension 1 (for short, codim 1) bifurcations like subcritical and supercritical Hopf bifurcation. The analysis of codim 1 bifurcation can be completed based on one bifurcation parameter. However, two bifurcation parameters should be considered to give a general view of the motion of the system when it undergoes a degenerate Hopf bifurcation. This kind of bifurcation named the generalised Hopf bifurcation belongs to the codimension 2 (for short, codim 2) bifurcations where two bifurcation parameters need to be taken into consideration. In this paper, we give a numerical analysis of the codim 2 bifurcations of a nonlinear railway wheel-set with the QR algorithm to calculate the eigenvalues of the linearised system incorporating the Golden Cut method and the shooting method to calculate the limit cycles around the Hopf bifurcation points. Here, we found the existence of a generalised Hopf bifurcation where a subcritical Hopf bifurcation turns into a supercritical one with the increase of the bifurcation parameters, which belong to the codim 2 bifurcations, in a nonlinear railway wheel-set model. Only the nonlinear wheel/rail interactive relationship has been taken into consideration in the lateral model that is formulated in this paper. The motion of the wheel-set has been investigated when the bifurcation parameters are perturbed in the neighbourhood of their critical parameters, and the influences of different parameters on critical values of the bifurcation parameters are also given. From the results, it can be seen that the bifurcation types of the wheel-set will change with a variation of the bifurcation parameters in the neighbourhood of their critical values.     

盾构隧道同步注浆新型双液注浆材料的研究与应用

盾构隧道的上浮易导致隧道管片错台、破损、渗漏和隧道超限等问题,进而影响到地铁隧道的验收与运营。通过分析管片上浮的主要原因,提出改进同步注浆设备,并在盾尾处采用常规同步浆液与聚丙烯酰胺水溶液(双液浆)相混合注入管片与开挖面之间的空隙。通过实验分析得出,注入空隙处的双液浆短时间内增稠,浆液成为塑性体,使管片的浮力降低许多,抗水分散性明显提高。通过实际应用,此种新型双液浆有效地填充了管片与开挖面之间的间隙,使隧道上浮量明显降低,提高了成型隧道的质量,解决了盾构隧道上浮的难题。     

Adaptive control of the shifting process in automatic transmissions

This paper focuses on the way of keeping shift quality of automatic transmissions consistent in mass production and with mileage accumulation. We investigate the main factors influencing the consistency of shift quality. Test results show that the torque to pressure (T2P) and pressure to current (P2I) characteristics of shifting elements are easily affected. A simulation model of an 8-speed automatic transmission is established to simulate the dynamic process of clutch-to-clutch shift. Simulation results demonstrate that the change of T2P and P2I characteristics has a significant influence on shift quality. In order to compensate for the influences, we develop two adaptive control strategies, i.e., the adaptive control strategies for torque phase and inertia phase. They make use of the measured speed information and time information to evaluate shift quality. Then the control parameters are tuned to adapt to the change of T2P and P2I characteristics. Vehicle tests verify that the developed adaptive control strategies are effective to keep shift quality consistent in mass production and with mileage accumulation.     

基于岩土控制变形工法的公路隧道施工变形分析——以野猪山隧道为例

宁波野猪山公路隧道右线出口段埋深浅、围岩差,采用岩土控制变形工法施工。该工法在我国公路隧道施工中几乎未有使用。本文通过数值模拟和现场监测数据对比分析,得出:1)隧道地表沉降的开挖空间效应约为0.6倍跨径,并据敏感程度划分为沉降敏感区、敏感过渡区、稳定区3个区域;2)隧道拱顶沉降约60%发生在掌子面到达监测断面前,开挖空间效应稍大于单倍跨径;3)隧道掌子面挤出变形呈外凸抛物面形态,建议施工中纤维锚杆的搭接长度设为6 m,并据挤出变形发展速率划分为快速发展、稳定发展、基本稳定3个阶段。     

灵江特大桥连续梁施工应力监控中消除温度影响的方法

新建甬台温铁路灵江特大桥由若干简支梁和一联连续梁组成,其连续梁跨度布置为(70+3×120+70)m。桥梁地处浙江省临海市,夏日最高气温超过40℃。温度对施工应力监控的影响很大,如果不消除温度的影响,应力测试难以进行。从理论分析方面对温度的影响作了论述。结合实际应力监控,论述应变采集仪和传感器的选型,从多方面论证温度对测试结果的影响规律,最终把应力测试误差减小到5%以下,达到了施工监控的目的。     

北京、香港、纽约城市轨道交通投融资模式对比分析

投融资模式的设计和选择是城市轨道交通项目科学决策中的关键环节.通过对北京、香港、纽约三个典型城市轨道交通投融资模式的分析,初步总结出三个城市在投融资模式上的特点.在分析差异性的基础上,对北京的城市轨道交通投融资模式提出相关政策建议,如允许轨道交通投资经营主体经营公共汽车业、旅游业、广告业、沿线房地产业及商业等与轨道交通相关联的行业,以提高轨道交通企业的综合效益;实施多元化的经营战略,吸引各种经济成分参与到轨道交通建设中来;政府在城市轨道交通投融资中发挥主导作用,以有效保证债务性融资的数量、期限、结构和成本;城市轨道交通建设项目投资比例不低于50%.     

无线通信技术在城市轨道交通中的应用

介绍了当前几种主流无线通信技术,并根据城市轨道交通承载业务需求、对实际传输速率等进行了比较,简单介绍了得力风根公司的TRainCom技术,据此对城市轨道交通无线通信系统提出整合的建议。     

浅谈广珠城际轨道线建设与中山市交通发展的互动关系

广珠城际轨道交通即将建成通车,这将在很大程度上改变中山市的市域交通格局。从长途客运交通、市域公共交通、小汽车交通等方面,论述广珠城际轨道交通对中山市市域交通系统的影响;探讨中山市常规公共交通、出租车、私人交通和步行系统如何与城际轨道交通车站进行无缝接驳。     

浅谈地铁图纸信息化管理

通过分析西安地铁建设中图纸及文档管理的现状,阐述了建设信息化的必要性,提出了地铁建设信息化实施策略,并对信息化所带来的效益进行了分析。     

重庆轨道交通3号线国产综合监控系统软件平台的设计和实现

综合监控系统（ISCS）是一个功能强大、开放、模块化、可扩展的分布式控制系统。介绍了重庆轨道交通3号线综合监控系统的系统设计原则、系统构成以及集成和互联的系统,讨论了基于Unix服务器的国产综合监控系统软件平台的特点。