静载锚固性能试验影响因素分析

结合铁路工程钢绞线一锚具组装件的静载锚固性能试验检测,对影响试验结果的各种因素进行了分析,并指出相应的解决措施。提出试验过程的有效控制是试验科学性和数据结果可靠性的有力保证。     

永磁同步发电机PWM整流系统初步研究

针对传统发电机整流系统谐波含量大,功率因数低的特点,为永磁同步发电机设计了一套PWM整流系统,通过电流前馈解耦控制,实现有功无功解耦,实现发电机侧单位功率因数运行。实验结果验证了该控制方案的可行性,可有效减少发电机电流谐波含量,并能在发电频率较大范围变动时仍能保持系统稳定运行。     

盾构施工筹划原则及影响因素分析

以北京地铁4号线11合同段(灵境胡同-新街口)四站三区间的盾构施工筹划为例,重点分析影响盾构施工筹划的因素;以方案比较的方法,介绍了确定三区间总体筹划方案的详细过程.     

线路客流预测分析与运营组织设计

从运营需要出发,提出客流预测的年限和内容;通过对客流量级的阐述,分析客流预测三级数据,确定运营的规模;根据OD(起讫点)客流分析来研究行车交路,做出满载率和拥挤度的评价;最终确定车辆编组与行车密度的合理组合,形成系统全面的技术方案,使客流预测更好地为运营组织服务.     

香港地铁的安全风险管理

概述地铁有限公司在香港建立和实践安全风险管理体系的经验、运营铁路安全管理组织架构、工程项目各阶段的安全风险管理规划、主要安全风险管理任务及分析方法等.     

Predictive power of inspection outcomes for future shipping accidents – an empirical appraisal with special attention for human factor aspects

This paper investigates whether deficiencies detected during port state control (PSC) inspections have predictive power for future accident risk, in addition to other vessel-specific risk factors like ship type, age, size, flag, and owner. The empirical analysis links accidents to past inspection outcomes and is based on data from all around the globe of PSC regimes using harmonized deficiency codes. These codes are aggregated into eight groups related to human factor aspects like crew qualifications, working and living conditions, and fatigue and safety management. This information is integrated by principal components into a single overall deficiency index, which is related to future accident risk by means of logit models. The factor by which accident risk increases for vessels with above average compared to below average deficiency scores is about 6 for total loss, 2 for very serious, 1.5 for serious, and 1.3 for less-serious accidents. Relations between deficiency scores and accident risk are presented in graphical format. The results may be of interest to PSC authorities for targeting inspection areas, to maritime administrations for improving asset allocation based on prediction scenarios connected with vessel traffic data, and to maritime insurers for refining their premium strategies.     

Effect of Seismic Parameters on the Safety Factor for an Underground Cavern北大核心CSCD

In order to quantitatively evaluate the safety of the surrounding rock of an underground cavern under seis-mic load, a comprehensive evaluation method for the stability of surrounding rock is proposed based on the general safety factor and point safety factor. A calculation method for the general safety factor of a cavern based on the prin-ciple of shear strength reduction of a rock mass is given, the run-through of the plastic zone between the main power-house and main transformer room is presented as a critical criterion for the overall instability of the cavern, and the general safety factor is obtained by searching for the reduction coefficient. A point safety factor calculation method based on the Mohr-Coulomb yield criterion is given. The influence of different seismic input parameters on the general safety factor of the cavern and the point safety factor of key positions are studied based on an underground power-house cavern of a hydropower station in Southwest China. The results show that the quantitative evaluation method for the stability of the surrounding rock based on the safety factor is feasible and can reflect the general safety de-gree and local safety degree of different positions of the cavern for different working conditions. It is found that the general safety factor of the cavern and the point safety factor of key positions decrease with an increase of the ampli-tude and duration of a seismic wave while they increase with an increase of the incident angle; additionally, the low frequency of a seismic wave has a great influence on the cavern while the high frequency has little effect. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

On Safety in Dismantling Temporary Strut of Super-large Tunnels with Double-layer Primary Support北大核心CSCD

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.     

Risk assessment framework for exposure of cargo and ports to natural hazards and climate extremes

There is an increase in risks and catastrophic losses in maritime transport including ports and cargo. Significant losses have been associated with large scale natural hazards, such as earthquakes, tsunami, cyclones, and other extreme weather events. This paper identifies the main gaps in understanding maritime risks in transportation research. The gaps are attributed to insufficient empirical work available from the maritime transport and logistics research community to guide multi-risk and natural hazards impact assessment on seaport and cargo. In addition, disaster studies communities have barely made adequate efforts to understand and assess port and cargo risks arising from multi-hazards and disaster events. This paper examines existing conceptual frameworks concerning exposure and risk assessments of natural catastrophe’s impacts. Furthermore, the paper identifies trends and gaps in risk assessment frameworks in the field of disaster studies that can be beneficial for maritime risk research. The authors propose a new risk assessment framework that can guide future research and multi-hazard risk assessment processes at different scales of maritime risks.     

A latent class accelerated hazard model of social activity duration

Over the past decade, activity scheduling processes have gained increasing attention in the field of transportation research. However, still little is known about the scheduling of social activities even though these activities account for a large and growing portion of trips. This paper contributes to this knowledge. We analyze how the duration of social activities is influenced by social activity characteristics and characteristics of the relationship between the respondent and the contacted person(s). To that end, a latent class accelerated hazard model is estimated, based on social interaction diary data that was collected in the Netherlands in 2008. Chi-square tests and analyses of variance are used to test for significant relations between the latent classes and personal and household characteristics. Findings suggest that the social activity characteristics and the characteristics of the relationship between the socializing persons are highly significant in explaining social activity duration. This shows that social activities should not be considered as a homogenous set of activities and it underlines the importance of including the social context in travel-behavior models. Moreover, the results indicate that there is a substantial amount of latent heterogeneity across the population. Four latent classes are identified, showing different social activity durations, and different effects for both categories of explanatory variables. Latent class membership can be explained by household composition, socio-economic status (education, income and work hours), car ownership and the number of interactions in 2 days.