利用轴载谱分析高速公路水泥路面当量轴载换算系数

利用江苏省不同地区20条高速公路上2004～2006年所有货车和大客车的动态称重数据,分析确定了各自的轴载谱参数;比较了我国和AASHTO 1993水泥路面设计方法中轴载换算公式的区别,分别利用这两种方法确定了各种车型的当量轴载换算系数以及混合交通的累计轴载作用次数, 为路面结构分析和设计提供参考,并指出在参考国外相关指标和典型的路面结构时,应当注意由于国、内外水泥路面轴载换算公式不同而造成的差别.     

悬索桥重力刚度法及主缆水平拉力计算

对于大跨度悬索桥,加劲梁的抗弯刚度远远小于具备强大拉力储备的主缆的重力刚度,加劲梁的抗弯刚度的大小对全桥结构行为的影响只是处于次要地位。忽略加劲梁的抗弯刚度而将悬索桥当成一个单纯的索结构来分析它的内力和变形的方法就是重力刚度法。通过与悬索同跨简支梁的剪力和弯矩来明确重力刚度的概念,并揭示该剪力和主缆水平拉力、该弯矩和主缆挠度之间的关系。分别采用重力刚度法和通用软件ANSYS来计算悬索桥的内力和变形,其结果接近,说明采用重力刚度法计算的结果也是具有参考价值的。     

Analysis of interaction factors between two piles

A rigorous analytical method is presented for calculating the interaction factor between two identical piles subjected to vertical loads. Following the technique proposed by Muki and Sternberg, the problem is decomposed into an extended soil mass and two fictitious piles characterized respectively by Young＇s modulus of the soil and that of the difference between the pile and soil. The unknown axial forces along fictitious piles are determined by solving a Fredholm integral equation of the second kind, which imposes the compatibility condition that the axial strains of the fictitious piles are equal to those corresponding to the centroidal axes of the extended soil. The real pile forces and displacements can subequally be calculated based on the determined fictitious pile forces, and finally, the validity of the proposed approach and desired pile interaction factors may be obtained. Results confirm the portray the influence of the governing parameters on the pile interaction.     

基于时间地理学的居民活动空间测度方法研究

活动空间能够反映居民受到的时空制约以及移动自由度，对分析居民出行行为有重要研究意义.本文基于时间地理学理论，强调时间维度对个体活动空间的重要塑造作用，引入活动持续时间作为权重因子，构建了活动空间的时空重心测度模型，提出“偏移度”“扩展度”两个概念来量化个体活动空间，并与传统空间中心测度方法进行对比分析，最后，以昆明市居民调查数据进行实例验证.结果表明，活动空间是由时间和空间两大要素共同决定，当存在出行距离大于4 km以上，偏移度对空间测度的修正程度约为5%~15%，时间要素对活动空间的影响程度变得较为敏感.     

Approximate weight functions of stress intensity factor for a wide range shapes of surface and an embedded elliptical crack

This paper describes the application of weight function for stress intensity factor in a surface crack with a wide range of crack shapes. Based on the weight function representation proposed by Wang and Glinka (2009), an extended formulation of the weight function for surfaces and embedded cracks is performed. The unknown parameters in the formulations were determined from reference values of stress intensity factor for a surface and an embedded crack given by finite element analysis with the J integral method. The effectiveness of the proposed weight functions has been verified by comparing with the stress intensity factors given by finite element analysis and available approximated solutions under several loading conditions.     

顺倾结构面红层岩质边坡稳定性分析及治理

含顺倾结构面的红层岩质边坡开挖过程中极易发生边坡失稳问题。本文以东南地区一公路红层岩质边坡为研究对象,分析该类边坡的致灾因子,并针对该边坡沿顺倾结构面的滑动破坏模式,提出坡脚堆载反压、刷方减载、夯填裂缝、设置排水工程和锚固工程的综合治理措施。通过建立滑坡模型,采用室内试验法、反算法和极限平衡法确定滑面计算参数和滑坡推力,并对治理措施实施过程中边坡稳定性进行分析验算,论证治理措施的可行性。监测数据表明,治理效果较为理想。     

抛石基床局部遭水冲破坏的诊断与加固

抛石基床发生局部破坏的工程实例较多,对出现该类问题的应对措施和相关加固技术的研究是迫切的。文中总结了大马力拖轮在靠离泊作业中造成使用期间重力式码头抛石基床局部被冲坏等主要原因,对抛石基床局部破坏问题的检测、诊断和安全性评估技术进行了探讨,并对各种抛石基床的加固方法加固效果进行了概括,最后提出了对码头管理单位在码头使用和维护的建议。     

驾驶舱眩光仿真分析与实车评价

良好的汽车驾驶舱视觉舒适性能够保障驾乘人员的行车安全，提高道路交通的稳定性，因此汽车驾驶舱的人机工程布置和内饰设计需要考虑减少驾驶舱眩光的产生。针对该问题，提出了一种基于CATIA/SPEOS的汽车驾驶室眩光评估方法。利用光线追踪法分析产生光反射部件之间的几何位置关系，在考虑材质属性、外界环境、真实光学效果和阳光照射方向的前提下，利用视觉仿真精确映射汽车驾驶舱的眩光位置。以某型SUV驾驶舱为例，通过光线跟踪分析发现，组合仪表不会有光线的直接照射产生眩光，中控大屏幕会有通过天窗和右边侧窗玻璃的光线直接照射产生眩光；通过视觉仿真分析发现，组合仪表由于光线折反射导致轻微眩光，中控大屏幕眩光面积较大；前挡风玻璃区域在中午和下午眩光较为严重，左边外后视镜区域在下午有空调镀铬装饰和风口造型的成像；中控大屏幕贴合AR防眩光膜优化后，分析结果表明，整块屏幕视觉效果趋于一致，视觉功效有显著提高。通过制定驾驶舱炫目主观评价流程并进行主观评价分析，得出驾驶舱眩光主观评价分析结果与仿真方法评估结果一致，表明该评估方法在新车研发和车型改款试制前期对驾驶室眩光分析和优化具有可行性。     

Crash risk factors associated with injury severity of teen drivers

This paper focuses on identifying crash risk factors associated with injury severity of teen drivers. Crash data obtained from the Highway Safety and Information System (HSIS) for the entire state of North Carolina, for years 2011 to 2013, was used for analysis and modeling. Among all the crashes during the study period, a total of 62,990 crashes involving teen drivers (15 to 19?years) were analyzed. A partial proportionality odds model was developed to identify factors contributing to injury severity of teen drivers. The results obtained indicate that teen drivers driving sports utility vehicles and pickup trucks are more likely to be severely injured when compared to teen drivers driving passenger cars. Teen drivers are more likely to be severely injured on weekdays, particularly during peak hours. The chances of teen drivers getting involved in severe injury crashes on Tuesdays and Fridays is higher when compared to Sundays. Age, gender, road configuration, terrain, adverse weather condition, and access control are observed to have a significant effect on teen driver's injury severity.     

Dynamic anti-plane interaction between an impermeable crack and a circular cavity in an infinite piezoelectric medium

Wave propagation in an infinite elastic piezoelectric medium with a circular cavity and an impermeable crack subjected to steady-state anti-plane shearing was studied based on Green＇s function and the crack-division technique. Theoretical solutions were derived for the whole elastic displacement and electric potential field in the interaction between the circular cavity and the impermeable crack. Expressions were obtained on the dynamic stress concentration factor （DSCF） at the cavity＇s edge, the dynamic stress intensity factor （DSIF） and the dynamic electric displacement intensity factor （DEDIF） at the crack tip. Numerical solutions were performed and plotted with different incident wave numbers, parameters of piezoelectric materials and geometries of the structure. Finally, some of the calculation results were compared with the case of dynamic anti-plane interaction of a permeable crack and a circular cavity in an infinite piezoelectric medium. This paper can provide a valuable reference for the design of piezoelectric actuators and sensors widely used in marine structures.