乘潮水位估计的逐时潮位统计法

针对海岸港口的乘潮水位计算问题,提出了逐时潮位法计算给定延时和保证率条件下的乘潮水位。该方法从潮位过程线上读取逐时潮位观测资料对应的持续时间,按潮位和延时分组进行二维统计,从统计结果中抽取所需计算延时的潮位序列,根据序列绘制累积频率曲线得到所需保证率的潮位值。该方法与规范法的计算结果相差不大,但在绘制累积频率曲线能减少约50%的计算量,将有效减少机时,提高工作效率。通过该方法计算得到了日照港年和季的乘高潮水位,计算结果表明船舶在乘潮进入日照港时,需特别考虑季节因素的影响。     

重力式码头方块墙沉降与旋转计算方法

基于分层总和法计算沉降的原理,推导了干施工条件下重力式码头方块墙沉降与旋转的理论计算方法,并对重力式码头试验段的沉降与旋转实测值与计算值进行了对比分析。结果表明:方块墙沉降与旋转的计算值与实测值变化规律一致,沉降与旋转均随着方块安装层数的增加而增大,但墙后回填碎石和墙上预压荷载后,墙趾处沉降继续增大,墙踵处沉降减小,并且墙体的旋转在预压后达到最大值。在重力式码头工程中推导的理论计算方法可应用于预判码头方块墙的沉降和旋转量、评价方块墙的预压效果以及预估现浇混凝土垫层的预设坡度。     

意大利威尼斯离岸深水港自动化集装箱码头结构选型

意大利威尼斯离岸深水港项目拟在外海建设现代化全自动集装箱港区,其关键技术之一是在深厚高压缩性土体且广泛存在极软弱泥炭夹层的极不均匀和复杂地质条件下,采用何种码头结构形式才能满足全自动化集装箱码头较高的使用要求。为此,对高桩码头+组合式桩基承台驳岸结构、重力式沉箱结构和全高桩(高桩码头+高桩堆场)结构3种方案进行综合比选,并利用有限元数值模拟分析,提出采用全高桩码头结构形式。该结构形式适合工程的地质条件和使用要求,技术成熟,风险小,且投资较低。     

特种半潜式无人航行器的优化设计

提出一种新型特种半潜式无人航行器方案,并对该航行器方案开展主尺度初步拟定和舱室划分等总体设计工作。基于STAR CCM+软件对该型航行器的水动力性能进行数值仿真分析,分析结果可作为推进系统设计及船型主尺度优化的依据。结合实际工程产品需求分析制约航行器推进系统设计的影响因素,分析续航力、航速、主机功率及电池质量之间的匹配关系,同时提出基于约束关系的主尺度优化方法。最后针对性能校核及数值仿真中发现的问题,提出半潜式无人航行器的进一步优化方案。     

Flexible Overlap Technology for the Lining Trolley of Single-track Railway Tunnels北大核心CSCD

Falling-off of rock piece at tunnel arch and invert heave are the main potential safety problems affecting normal operation of the railway tunnel. The reasons causing falling-off of rock piece include squeezing by lining trol⁃ ley at construction joint, concrete cutting by cantilever end of water stop at construction joint, construction cold joint at arch, concrete quality deficiency and so on. To eliminate the falling-off of rock piece at tunnel arch caused by rig⁃ id overlap, modification of lining trolley and the flexible overlap technique combining tray with rubber gasket were adopted during the construction of Nuwashan tunnel on China-Laos railway, and the potential quality problem due to rigid overlap at construction joint of tunnel lining were effectively solved. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Experimental and Numerical Study on the Behaviors of Deep-Buried Water-Storage and Drainage Shield Tunnels北大核心CSCD

Deep-buried water-storage and drainage shield tunnels, which are different from road and subway shield tunnels in terms of computation theory, construction technology and operation maintenance, would bear high inner water pressure and large earth pressure. In view of the change of the bearing mode for the lining structure of water-storage and drainage shield tunnels, a full-ring test and numerical analysis are carried out to study the influence of inner water pressure, staggered joint assembly and bolt installation types on the behaviors of water-storage and drainage shield tunnels. The results show that the deformation of the straight-jointed water-storage and drainage shield tunnel varies greatly from the state of empty water to that of full water; and the vertical and horizontal convergence deformations of the tunnel with inner water pressure of 0.6 MPa are 2.2 times and 3.2 times of that without inner water pressure, respectively. The convergence deformation, and the maximum joint opening and bolt tension of stagger-jointed lining structure decrease by 15%-25% and 25%- 40%, respectively, compared with that of the straight-jointed water-storage and drainage shield tunnel. The bolts at the segmental joints will yield because of the increase of inner water pressure and the first occurrence of bolt yield phenomenon is located near the position on the lining structure which is under the action of maximum negative bending moment; because the failure of shield tunnel is always caused by the yield of joint bolts, this position is the weak point for the deep-buried water-storage and drainage shield tunnel. For the water-storage and drainage shield tunnel based on the connection with double rows of bolts, the bolts near the outer arc surface of segmental joints in the area of 90 degree in the vault and arch bottom can be removed; the bolts near the inner arc surface of the segmental joints within the 90 degree of the haunch must be installed, otherwise, the tensile force of the bolts at the segmental joint near the maximum negative bending moment will increase by 5%-14%. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

全平衡垂直升船机提升系统研究

主提升系统是全平衡垂直升船机的关键设备,以水口全平衡垂直升船机为例,提出了承船厢运行速度曲线、控制承船厢与挡水门精确停位方法、事故紧急保护原理和关键参数计算方法。通过不同速度的试验,验证速度曲线的实用性。从运动学的角度分析了事故紧急保护的原理、确定关键参数的计算公式和方法。选择多组承船厢水深数据计算制动延迟时间和滑移行程,与现场试验数据基本相同,从理论和实践上验证了其原理的正确性。     

新型船舶燃油预热转运技术应用分析

针对传统船舶燃油加热技术存在的一些问题,介绍了一种新型燃油预热转运技术应用原理,并对该技术进行了实用性分析,提出了新船加装和老船改造该技术系统应考虑的相关问题。最终得出结论:新型燃油预热技术操作简捷,系统容易管理,实用性强,大大降低了蒸汽使用量,达到了节能减排双重功效,是值得应用于船舶的加热技术,对航运企业有一定借鉴意义和参考价值。     

What encourages people to carpool? An evaluation of factors with meta-analysis

Non-household carpools (where two or more commuters from different residences travel together in the same private vehicle) bring public benefits. To encourage and incentivise it, transport practitioners and researchers must understand its private motivations and deterrents. Existing studies often report conflicting results or non-generalisable findings. Thus, a quantitative systematic review of the literature body is needed. Using meta-analysis, this study synthesised 22 existing empirical studies (representing over 79,000 observations) to produce an integrated review of the carpooling literature. The meta-analysis determined 24 non-household carpooling factors, and their effect sizes. Factors such as number of employees (\(\bar{r} = 0.42\)), partner matching programs (\(\bar{r} = 0.42\)), female (\(\bar{r} = 0.22\)) and fixed work schedule (\(\bar{r} = 0.15\)) were found to have strong effects on carpooling while judgmental factors (such as the motivation to save costs) only exhibited small influence (\(\bar{r} < 0.1\)). Based on the significant effects, the paper discussed prospects for improving carpooling uptake by developing: (i) target demographics, (ii) selling points for marketing, (iii) carpooling partner programs and (iv) multiple employer ‘super-pools’. The results warrant caution due to the small amount of studies synthesised. Transport practitioners might plan carpooling policies based on the findings; and transportation researchers might use the list of factors to model carpooling behaviour.     

嵌入式数据库在桥梁实时监测系统中的应用

介绍了嵌入式数据库特点及Berkeley DB数据库体系结构,结合桥梁健康实时监测系统的具体需求,设计了一种基于嵌入式数据库Berkeley DB的桥梁监测系统结构,并给出了关键的数据库中数据处理的设计实现.简单讨论了该结构系统的扩展性和改进问题.