30 000 DWG散货船码头系泊模型试验研究

对30 000 DWG散货船在开场水域码头系泊开展了模型试验研究。在风浪流组合工况中,对不同系泊方式的系缆张力和船舶运动进行了分析。分析结果表明,流向和缆绳长度对系缆张力有显著影响。试验结果可为类似船舶码头安全系泊提供重要技术参考。     

高海拔特长隧道低温大风环境及对围岩-结构温度场的影响

为探明高海拔特长隧道洞外低温大风的成因、特征及对洞内风场、围岩-结构温度温度场的影响,以国道317线雀儿山隧道为工程依托,采用气象站、手持风速仪、红外测温仪、埋入式多点铂电阻温度传感器等,对冬季隧道贯通前后进出口两端隧址区、洞内净空风速、风向、温度以及隧道轴向、径向的围岩-结构温度场进行现场实测,分析低温大风成因和特征、隧道贯通前后负温区范围、风速风向变化规律以及对洞口段和洞深部围岩-结构温度场的影响。研究结果表明：受高原大尺度大气环流产生的高原季风以及雀儿山两侧日照时间、地形引起的小尺度范围内自由大气热力差影响,隧址区冬季风速高、温度低;大风时段主要集中在14：00~21：00,平均风速达10 m·s^-1,负温时段主要在19：00~8：30,隧道进、出口日最大气温差分别为23.5℃和28℃;隧道贯通前,进出口两端负温区段在860 m以内;贯通后,出口端主洞和平导负温区段为1 200,1 280 m,分别比进口端长了340,420 m;贯通前后,隧道深部最低风速分别为1.1,2.2 m·s^-1,洞内风向由两端向洞内方向转化为主要由出口向进口方向;隧道洞口浅埋段围岩和衬砌结构径向负温范围在贯通前为1.20 m,贯通后为0.80 m,且在上述范围内温度变幅较大;低温大风对隧道深部的围岩温度影响不大,但对结构表面温度影响明显,由于变温区主要集中在二衬混凝土结构内部,因此要重视结构内部产生的冻胀作用。     

试述国内外公路设计理念的发展

更新公路建设理念的前提和核心是要更新设计理念,只有做到不断地更新设计理念,才能确保公路建设的可持续发展.     

基于驾驶负荷的山区二级公路纵坡路段驾驶舒适度评价研究

为定量评价山区公路纵坡路段驾驶舒适度，本文以云南省文都二级公路为研究对象，进行实车试验开展驾驶负荷研究.首先，分析上、下坡路段坡度、坡长、加(减)速度指标对驾驶负荷影响程度，运用多元回归建立驾驶负荷模型；其次，利用心率增长率的第50、85分位值划分驾驶舒适度，结合所建模型对驾驶舒适度进行阈值分析，确定不同驾驶舒适程度对应坡度、加(减)速度区间范围；最后，对模型及阈值划分合理性进行分析验证.结果表明，坡度、加 (减)速度对纵坡路段驾驶负荷皆为显著变量，而坡长与驾驶负荷仅存在弱相关性.本文模型有效，阈值划分合理，可为低等级公路驾驶负荷研究提供参考.     

A day-to-day dynamical model for the evolution of path flows under disequilibrium of traffic networks with fixed demand

Transportation networks are often subjected to perturbed conditions leading to traffic disequilibrium. Under such conditions, the traffic evolution is typically modeled as a dynamical system that captures the aggregated effect of paths-shifts by drivers over time. This paper proposes a day-to-day (DTD) dynamical model that bridges two important gaps in the literature. First, existing DTD models generally consider current path flows and costs, but do not factor the sensitivity of path costs to flow. The proposed DTD model simultaneously captures all three factors in modeling the flow shift by drivers. As a driver can potentially perceive the sensitivity of path costs with the congestion level based on past experience, incorporating this factor can enhance real-world consistency. In addition, it smoothens the time trajectory of path flows, a desirable property for practice where the iterative solution procedure is typically terminated at an arbitrary point due to computational time constraints. Second, the study provides a criterion to classify paths for an origin–destination pair into two subsets under traffic disequilibrium: expensive paths and attractive paths. This facilitates flow shifts from the set of expensive paths to the set of attractive paths, enabling a higher degree of freedom in modeling flow shift compared to that of shifting flows only to the shortest path, which is behaviorally restrictive. In addition, consistent with the real-world driver behavior, it also helps to preclude flow shifts among expensive paths. Improved behavioral consistency can lead to more meaningful path/link time-dependent flow profiles for developing effective dynamic traffic management strategies for practice. The proposed DTD model is formulated as the dynamical system by drawing insights from micro-economic theory. The stability of the model and existence of its stationary point are theoretically proven. Results from computational experiments validate its modeling properties and illustrate its benefits relative to existing DTD dynamical models.     

Evaluation of total risk exposure and insurance premiums in the maritime industry

The empirical evaluation of maritime risk exposure is based on the monetary value at risk (MVR) that incorporates individual safety quality data of about 130,000 vessels, insurable values related to various potential damages, and proxies for fractions of values lost at incidents. MVR provides a tool to enhance strategic planning of maritime administrations and insurance providers, which is illustrated by a high level comparison of annual risk exposure with insurance premiums for 2010–2014. The analysis reveals a global annual insurable value of 30.6 trillion USD with associated annual MVR of 38.8 billion USD for very serious and serious incidents. Although oil tankers show the highest risk exposure (1.75 million USD per tanker per year), safety qualities are found to be best for this ship type (1.4% annual incident risk) and worst for container vessels (2.8%). Annual growth rates in total risk exposure are mostly positive with highest value for dry bulk carriers (27.8%), whereas risk exposure tends to decline for pollution of oil tankers (−2.0%) and passenger vessels (−11.3%), and for loss of life of oil tankers (−1.9%) and dry bulk carriers (−1.4%). Comparison across administrative dimensions reveals that most risk exposure lies with old open registries and with beneficial owners and the Document of Compliance companies located in high income countries. Comparison with global insurance premiums suggests reasonably adequate coverage of maritime risks (excluding cargo) with under-insurance of risk by around 5% (about 1 billion USD per year), with some uncertainties remaining for actual loss fractions of the involved damages.     

刘家峡大桥桥台岸坡岩体特性及其稳定性研究

刘家峡大桥位于刘家峡水库右岸冲沟沟口,是临夏折桥至兰州市达川二级公路的控制性重点工程.该桥设计采用单跨悬索桥方案（跨径20 m＋536m＋20m）,建成后将成为甘肃省乃至北方地区最大跨度的桥梁.通过地质调绘、工程钻探、平硐勘探、岩体声波测试、大型原位岩体变形试验和室内力学试验多种方法,对桥台岸坡岩体特性进行了详细研究.基于变形理论,运用Geo-Studio和FLAC数值模拟软件对库水位升降、桥基开挖、桥塔荷载等因素影响下的桥台岸坡的稳定性进行了研究,最后并就桥台岸坡防治措施提出了建议.     

对船舶号灯、号型条款中常见误解类型的剖析

号灯、号型是船舶不可或缺的组成部分,是识别和判断船舶类型、大小、动态和工作性质的主要手段.尽管《1972年国际海上避碰规则》规定了各种船舶在不同动态下应显示的号灯或号型,但是由于船舶吨位增大,地方和港口主管机关对号灯、号型另行规定以及为满足当前操纵需要而设计的新型船舶出现,加大了对号灯、号型所提供的信息判断难度。本文以事故案例为引导,根据当前航行环境特点,对号灯、号型的规定进行有针对性的分析和研究。     

青少年学生参加体育锻炼的现状研究

针对我国青少年体质健康问题,对青少年学生参加体育锻炼行为现状进行了分析,为实施青少年体育运动的干预指导提供了依据。     

断层影响带地应力特征及稳定性验证

为研究分析福建某隧道两断层影响带的地应力场特征,在其隧道中部断层影响带附近两钻孔中采用水压致裂法进行了地应力测试.测试结果表明:断层影响带测试区地应力符合一般地应力分布规律,水平主应力随深度增加有增大趋势,局部裂隙导致部分测点应力值偏高或偏低;两测孔最大水平主应力方向一致,均为NNW向.该测试结果与区域构造应力场基本吻合,也接近于同区域围岩完整区地应力测试成果.文章根据该测试成果分析了该测试区的地应力特征,并采用滑动准则下限验证了两测孔所在的断层的稳定性.