Locating rental stations and bikeways in a public bike system

To determine the spatial distribution of rental stations and bikeways in a public bike system, this paper proposes a facility location and network design model. The model is developed as a multi-objective programing problem that considers four objectives (minimizing cyclist risk, maximizing cyclist comfort, minimizing adverse impacts on traffic and maximizing service coverage) and multiple constraints (monetary budget, network connectivity, station spacing, bikeway types, station number and value ranges of decision variables). The ε-constraint method solves the programing problem for the public bike system in Daan District, Taipei City, Taiwan. The nine non-dominated alternatives generated are all markedly better than existing locations of rental stations and bikeways. Scenario analysis results indicate that increasing the construction budget for bikeways significantly improves cyclist safety and comfort whilst increasing the adverse impact on traffic. Planners can use this model to develop public bike systems that spatially integrate rental stations and bikeway networks.     

Mechanism of Tunnel Water Inflow Caused by Bending Failure of a Waterproof Dike Based on a Circular Thin Plate Mechanical Model北大核心CSCD

Water bursts during tunnel construction endanger construction, and it is therefore necessary to reserve a waterproof dike with the required thickness to avoid water bursts and to take reinforcement of the dike and treatment of the structure liable to trigger a water burst. Using the water burst at K5+398 of the Mingyueshan tunnel of the Shanghai-Chengdu expressway as an example, and considering the type of tunnel section and the upright mudstone of the dike, the waterproof dike at the work face is simplified as a round thin plate. A formula for the calculation of a minimum safety thickness for the critical waterproof dike is deduced by analyzing the force applied on the water-proof dike, and the minimum safety thickness for the water burst section at K5+398 of the Mingyueshan tunnel is cal-culated. The numerical simulation analysis demonstrates the critical thickness of waterproof dike at K5+398 of the Mingyueshan tunnel is 1.4-1.55 m, and the calculated water inflow and water burst basically agree with the actual condition. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Model Test on Grouting Law in Dynamic Water-Rich Sand Layers by the Electric Resistance Method北大核心CSCD

In order to study the diffusion law of grouting slurry in the water-rich sand layer under flowing water conditions, a grouting test model consisting of a main test system, a grouting system, and a measurement system was developed. And for detecting the diffusion scope of the grouts, a new resistivity method was proposed. It is found that the relationship between grouting pressure and grouting rate during the test is strong. Under hydrodynamic conditions, the grouting slurry diffuses elliptically. Due to gravity and the effect of the upper water flow, the center of gravity of the ellipsoid is below the grouting outlet, and the grouting effectively improves the physical and mechanical properties of water-rich sand bodies. At the same time, the resistivity method has a good application effect on the detection of grouting diffusion range. The range of slurry diffusion obtained by the resistivity method is basically consistent with the boundary of the stone body after excavation, indicating that the resistivity method is reliable for detection of grouting range in dynamic water-rich sand layer. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Analysis of the Circulation System of a Slurry Shield and the Muck Carrying Ability of a Dredging Pipe北大核心CSCD

The circulation system of a slurry shield is composed of a transportation system and a processing system.For shield construction, correct selection of the circulation system for the slurry shield is directly related to construc-tion speed. Using the Nanjing Yangtze tunnel as an example, the material balance calculation of the circulation sys-tem, sieving effect analysis, and analysis of the muck carrying ability of the dredging pipe are conducted for various strata. The practical results show that above mentioned calculations and analysis method provide a good reference for the proper selection of a slurry separation system and dredge pipe. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

柳江红花二线船闸输水系统布置与水力学模型试验研究

红花二线船闸是广西西江黄金水道首批重点建设项目,是提升柳江及西江通航能力、实现西江亿吨黄金水道的重要工程,其闸室规模与三峡船闸一致、工作水头近20 m、输水能量巨大。结合工程特点,选择了闸底长廊道侧支孔输水系统,设计了输水系统具体布置,并提出采用汇合廊道改善单边阀门运行输水流态的措施。通过比尺为1∶30的物理模型试验,对不同阀门运行工况下输水系统水力特性、闸室船舶停泊条件、进出水口水流条件等开展研究,推荐了使水力指标满足规范和设计要求的阀门开启方式。     

蜀山泵站枢纽船闸输水系统水力学模型试验

蜀山泵站枢纽船闸对引江济淮工程航运至关重要,是连通长江与淮河,确保引江济淮航运干线畅通的控制性工程,其闸室规模大、工作水头高、输水能量高,输水过程水力学问题是船闸设计的关键环节。结合工程地质和结构设计,船闸拟采用形式最为简单的闸墙长廊道侧支孔输水系统,输水过程船舶与船闸自身安全能否满足相关要求需要开展细致研究。通过比尺为1∶25的物理模型试验,对其输水过程船舶停泊条件、水力特性及引航道水流条件开展研究。结果表明:在推荐的输水系统布置和阀门开启方式下,各项水力指标均能满足规范和设计要求。     

船舶岸电系统在集装箱码头的应用

靠港船舶岸电系统具有可以减少污染物排放和提高能源利用率的优点,正在我国港口大力推广。为探讨岸电系统在集装箱码头的应用前景,以大窑湾北岸某集装箱码头为例,利用仿真模型核算多种情景下2020年大窑湾北岸集装箱码头船舶使用岸电前后的碳排放量,并分析不同装卸效率对船舶的碳排放的影响。结果表明,集装箱码头使用岸电系统可实现低碳效益,提高装卸效率有利于船舶碳排放的减少,但应考虑提高装卸效率会引起装卸机械碳排放增加。     

不规则波作用下的港域波浪条件试验研究

针对数学模型很少能较好地模拟天然海浪的多向性、不规则性的特点,基于港口波浪整体物理模型试验,对不规则波作用下港域内测点的波高扰动系数的分布规律进行研究。结果表明:在绕射作用为主的掩护区域,多向波的绕射性能大于单向波,波浪扰动系数较大;波浪绕射、反射作用均十分强烈的掩护区域,多向不规则波与单向不规则波的扰动系数看不出明显的大小关系。以反射作用为主的掩护良好区域,单向不规则波的扰动系数较多向不规则波的要大,且受反射作用越大的区域,单向波的扰动系数大的越多。在以绕射作用为主的掩护区域,波浪分布对周期的敏感性较差;在以反射作用为主的掩护良好区域,波高分布对周期的敏感性较强。在绕射、反射都较强的情况下有可能单向波作用下的港内波高大于单向波,用单向不规则波来模拟反而是偏安全的。在进行港内波况整体模型试验时需要根据实际的工程条件做出综合考虑来决定波型,必要时要对单向、多向不规则波都要进行试验以确定最佳方案。     

景洪水力式升船机机械系统设计

结合景洪升船机的设计,对水力式升船机机械系统各子系统及部件的功能进行论述,对其结构和设计参数进行研究,并给出水力式升船机卷筒及同步系统、浮筒及动滑轮装置、钢丝绳组件和下水式承船厢的主要结构和设计参数。对水力式升船机浮筒的配重进行探讨,特别针对无间隙同步系统、承船厢充压对接密封装置提出新颖的结构,为同类工程设计提供参考。     

FPSO单点系泊系统安装及回接技术

单点系泊系统作为浮式生产储油卸油装置（Floating Production Storage and Offloading,FPSO）的核心组成部分,需在FPSO进入安装现场之前完成安装,随后FPSO进入安装现场进行回接。以我国南海某具体工程项目为背景,全面、系统地介绍FPSO悬链腿单点系泊系统的安装及回接方法,并采用OrcaFlex分析软件对各个施工步骤进行相关的模拟分析。该单点系泊系统的整个安装过程可分为抓地锚安装、下段锚腿铺设、锚腿张紧、上段锚腿铺设、单点浮筒拖航及就位和锚系回接单点浮筒等6个阶段。