水库滑坡涌浪爬坡特征试验研究

由滑坡引起的涌浪灾害不仅严重威胁航运安全,还会冲毁码头、大坝等水工建筑物并造成沿岸居民生命财产的损失。采用物理模型试验的方法对散粒体滑坡涌浪的爬坡特性开展了研究。试验结果表明:影响涌浪爬坡高度的主要因素有滑坡入水速度、滑坡体规模、滑动面倾角、水深、传播距离和爬坡角度等;当涌浪远场传播形态类似椭圆余弦波或孤立波时,涌浪爬坡高度较高,岸坡处水流紊动剧烈,涌浪对岸坡的破坏能力也最强。根据试验结果还建立了近岸坡处涌浪最大波幅计算模型,并结合经典波浪爬坡经验公式推导出了新滑坡涌浪爬坡高度计算公式。以长江新滩滑坡为例,验证了新涌浪爬坡高度计算公式的精度。研究结果能为实际工程中可能存在的滑坡涌浪爬坡灾害范围预测和涌浪避险方案制定等提供一定参考。

磁驱动双半球胶囊机器人爬坡运动分析

胃及肠道内表面布满环形皱襞,凹凸的复杂作业环境给磁驱动双半球胶囊机器人姿态能否稳定回归带来不确定性,且肠道起伏的表面迫使机器人应具备一定角度的爬坡行走能力。基于空间旋转磁场与机器人的随动效应,采用拉格朗日乘子法建立主动模态下爬坡滚动的完整动力学模型,通过姿态角仿真分析验证了模型的正确性。为进一步分析机器人的爬坡能力,建立简化动力学模型,结合由动量矩定理推导的纯滚动条件,仿真相关参数与纯滚动爬坡角度关系。仿真表明:机器人爬坡时姿态具备一定的抗干扰能力,且在规定范围内,增大磁场强度和摩擦因数,可以增强机器人的爬坡能力。上述结论为延展胶囊机器人的作业场合提供了理论支持。

新型变结构球形机器人运动分析

针对已有的变结构球型机器人在连杆爬坡机构展开状态下无法进行转弯的缺点,改进了原有机构,使其成为一种在两种运动模式下都可以进行原地零半径转弯的新型球形移动机器人。由于新型机器人的后轮也能提供驱动力,因此其爬坡能力也大大增强。建立新型变结构球型机器人爬坡和转弯的力学模型,并用仿真软件分别对新旧几款球形机器人的爬坡运动进行仿真对比分析,通过仿真分析验证了力学模型的正确性和新型机构对于增强机器人爬坡能力的有效性。在此基础上,对影响新型机器人爬坡能力的参数进行分析,为进一步提高机器人越障能力提供了理论依据。最后,通过样机试验进一步验证了力学模型的正确性、机器人的转弯灵活性和新机构对于增强机器人爬坡能力的有效性。

番禺大桥主塔施工技术

介绍了番禺大桥（主跨３８０ｍ斜拉桥）主塔的施工，对大斜度钻石型塔的施工技术进行了详细的总结，重点介绍管桩－贝雷梁混合支架、整体提升斜爬模、环向预应力束、预应力深埋锚的施工工艺。

基于信息生态理论的大数据治理建模及西部区域治理路径设计

[目的/意义]目前尚无区域信息压力的研究,西部区域大数据服务缺乏适应型的信息服务架构与模型设计,而作为大数据治理实施主体的当地政府,不发达地区治理路径选择与定量模型应用成为情报政策领域亟待解决的问题。[方法/过程]应用区域信息生态承载递阶结构理论,加入系统仿真模拟与动力学建模,针对治理区域所在社会环境、自然环境等系统内外部耦合作用效果及因子分析,分析并构建了区域大数据治理的作用模型。[结果/结论]首次构建了我国区域大数据治理的爬坡模型及定量评价;构成爬坡模型的3个大数据治理约束因子中,区域信息社会基础环境质地属于很难改变的自然弹性力,而信息社会发展需求因子为系统只能适应与接受的社会经济驱动力,唯有信息治理路径选择因子属于仅有的可调控、选择的制度力或政策力;区域信息治理的核心取决于该区域驱动力与支撑力的发展是否适应其阻滞力与压力水平,区域大数据中心作为关键的科学与扶贫治理的信息使能器,成为大数据治理基本的信息生态环境容纳与治理路径选择。

Adjustment of B3 model for drying concrete with additives based on experimental data

All currently avalable concrete creep predicting models cannot describe well the creep of a concrete structure because they all leave the effects of additives out of consideration. The purpose of this work was to modify model B3 for overcoming this deficiency. We tested thirteen specimens of C40 and C50 concrete with additives, out of which nine were for creep and four for shrinkage tests over a 700 d period under controlled temperature. We compared the experimental results for creep and shrinkage with those obtained by using model B3, and derived modification terms through regression analysis. Based on the experimental results of identical specimens under varied stress levels, we also derived a function considering the effect of stress level on creep. It is suggested that the creep prediction models without adjustment should not be used for modem concrete with a variety of additives.

Modification of B3 Model for Sealed Concrete with Additives Based on Experimental Observations

Thirteen specimens were tested out of which nine were for creep of sealed concrete and four for shrinkage test,for a period of 700 d under controlled temperature condition.The experimental results for creep and shrinkage were compared with creep and shrinkage computation model B3 and distinct discrepancies between observed and calculated creep and shrinkage strains were observed.Based on regression analysis,modification on B3 model has been formulated which will be applicable at least for concrete of characteristics strength of C40 and C50 with additives.Besides,on the basis of observation on identical specimens with varied stress strength ratio,a function is generated which accounts effect of stress strength ratio on creep.Finally,Civil Engineering community is suggested not to follow the creep prediction models without correction at least for modern concrete,as they do not account the effect of additives on its compliance function.

Model of tri-sectional wheel-based cable climbing robot and analysis of centrifugal safety landing method

This paper proposes a new type of tri-sectional wheel-based cable climbing robot which is able to climb up vertical cylindrical cables of a cable-stayed bridge. The robot is composed of three pairs of wheels equally spaced circularly which are joined by six connecting boards to form a whole closed hexagonal body to clasp a cable. The whole design is entirely modular to enable to assenably the robot on-siteeasy eaoily. To analyze the static features of the robot, a mathematical model of climbing is deduced. Furthermore, taking a cable with a diameter of 80mm as an example, we calculate the design parameters of the robot. For safly landing in the case of electrical accident, a centrifugal speed regulator is proposed and applied to consume useless energy generated when the robot is slipping down along the cables. A simplified mathematical model of the landing mechanism is deduced. Finally, several experiments on the climbing mechanism demonstrate that the robot can carry payloads less than 2.2kg to climb up a cable with diameters varying from 65mm to 205mm.

基于抗车辙性能的沥青路面长大纵坡界定标准

提出了基于抗车辙性能的沥青路面长大纵坡标准的界定方法。首先根据现场车辙调研数据对同济大学车辙预估模型进行标定,使之适用于具体工程;然后基于标定后的车辙预估模型和沥青路面容许车辙深度确定出车辆在长大纵坡上的临界车速;同时根据现场车速调研数据对汽车爬坡模型进行修正,使之反映车辆在长大纵坡上的实际车速变化;再根据修正后的汽车爬坡模型和车辙预估模型,推导出车辆在从坡底爬坡开始,达到临界车速时所行驶过的坡长,即为对应特定坡度的坡长限值;最后给出了多哥壹号公路改建工程中长大纵坡界定标准的实例。结果表明,基于沥青路面抗车辙性能长大纵坡界定标准较规范中基于行车安全的标准更为严格,可以作为规范中标准的补充。