冻土区道路翻浆的原因及影响因素

从土质、水分、温度、行车荷载、路面结构等几个方面对冻土地区道路翻浆的产生原因进行了分析并提出了防治措施。     

基于 Matlab PDE 工具箱的土体冻结温度场模拟研究

分析并运用Matlab PDE tool模拟模型槽土体冻结的温度场并验证模拟值的准确性。首先,通过合理的边界假设,使三维的模型槽土体冻结热传导问题转化为二维空间;然后,运用Matlab PDE tool进行模拟并对比测温点的模拟温度和实测温度。结果表明：土体冻结中温度场导热可以通过Matlab PDE tool模拟,且操作简单易于掌握;测温点模拟值的准确性与测温点距边界距离和冻结时间有关。     

季节性冻土地区客运专线路基基床结构优化

对季节性冻土地区客运专线的路基基床结构进行了优化,通过现场填筑试验证实优化后的路基基床填筑方案,即铺设两布一膜,上覆5 cm中粗砂,再铺设55 cm厚级配碎石达到了检验标准,可在所研究的工程中推广使用。同时提出采用C25纤维混凝土代替原设计8 cm沥青混凝土作为防水层,优化后的防水层在施工操作性和质量保证方面有较大优势。     

超大型矿砂船典型节点优化设计研究

以两条超大型矿砂船为例,采用节点细化有限元分析方法,对一系列高应力区域进行研究。以双层底局部短纵桁与内底/外底纵骨连接处、槽型横舱壁与纵舱壁相交处、边舱平面横舱壁水平桁趾部等位置为例,对应力集中节点的结构优化方案进行了比较计算,得到的结论对这些区域的节点设计具有一定指导意义。     

基于MS-RG混合图像分割模型的道路检测研究

道路场景因其结构的多样性、纹理变化的复杂性和自然曝光的不稳定性,使得传统基于道路分割的道路检测方法大多存在信息冗余,并且存在边界丢失、模糊等质量问题.本文首先在道路图像上使用 Meanshift均值漂移算法,通过空间内的概率密度呈梯形上升去寻找局部最优,并搜索属于同一模点的像素然后生成获得超像素块.然后利用 Meanshift算法获得的聚类超像素块进行多种子点区域生长,规范生长规则,克服不能得到封闭边界的缺陷,改进道路图像的分割效果.实验结果表明,本文提出的模型适用性强,相比于传统方法有效地提升了分割准确性和实时性,可准确识别出图像中的道路信息,确保车辆能够行驶在可行驶区域上.     

沿海滩涂区桩基施工

泉州后渚大桥位于大潮差滩涂区,引桥采用桩基筑岛施工,介绍筑岛施工要注意的问题及应对办法。     

Crash prediction model for two-lane rural highways in the Ashanti region of Ghana

Crash Prediction Models (CPMs) have been used elsewhere as a useful tool by road Engineers and Planners. There is however no study on the prediction of road traffic crashes on rural highways in Ghana. The main objective of the study was to develop a prediction model for road traffic crashes occurring on the rural sections of the highways in the Ashanti Region of Ghana. The model was developed for all injury crashes occurring on selected rural highways in the Region over the three (3) year period 2005–2007. Data was collected from 76 rural highway sections and each section varied between 0.8 km and 6.7 km. Data collected for each section comprised injury crash data, traffic flow and speed data, and roadway characteristics and road geometry data. The Generalised Linear Model (GLM) with Negative Binomial (NB) error structure was used to estimate the model parameters. Two types of models, the ‘core’ model which included key exposure variables only and the ‘full’ model which included a wider range of variables were developed. The results show that traffic flow, highway segment length, junction density, terrain type and presence of a village settlement within road segments were found to be statistically significant explanatory variables (p < 0.05) for crash involvement. Adding one junction to a 1 km section of road segment was found to increase injury crashes by 32.0% and sections which had a village settlement within them were found to increase injury crashes by 60.3% compared with segments with no settlements. The model explained 61.2% of the systematic variation in the data. Road and Traffic Engineers and Planners can apply the crash prediction model as a tool in safety improvement works and in the design of safer roads. It is recommended that to improve safety, highways should be designed to by-pass village settlements and that the number of junctions on a highway should be limited to carefully designed ones.     

空间六索面斜拉桥钢桥塔拉索锚固区受力分析及结构优化

依据钢桥塔的结构形式和受力特点,建立钢桥塔节段的板壳有限元模型,对索塔锚固区进行有限元静力分析,得出索塔锚固区的应力分布特征,通过减小塔壁与横隔板厚度、在锚固区支撑加劲肋间加水平加劲肋等对锚固区的结构进行优化,使上横隔板的应力集中现象得到了很好的解决,且传力较流畅。     

季冻区半刚性基层材料工程特性试验研究

以季冻区道路的半刚性基层为背景,对石灰稳定土和二灰稳定土的最佳干密度、无侧限抗压强度和冻胀量进行了研究。经过试验得出季冻区石灰稳定土基层中石灰剂量为14%~16%时强度相对较大,是抑制冻胀发育的最佳石灰剂量;影响二灰土强度的首要因素是二灰用量,季冻区二灰稳定土基层的合理二灰含量约为30%,二灰比1 2(石灰粉煤灰土=10 20 70)为季冻区二灰土最佳配合比,该配合比强度大,抑制冻胀发育效果较好。     

寒区隧道冻胀压力的约束冻胀模型

评价了中国主要的冻胀压力分析模型,在存水空间模型的基础上,分析了冻胀水体的形变约束特征,提出了冻胀压力类似于气体压力的约束冻胀模型,并给出了相应的理论分析公式;计算分析了冻胀压力的作用位置、冻胀水体尺度、围岩和衬砌刚度等对衬砌结构安全度的影响及分布规律。结果表明:该模型表现了冻胀压力为局部荷载的特征,同时考虑了衬砌和围岩刚度对冻胀压力的影响,并可模拟存水空间内的冻胀水体为任何多面体形状;增加衬砌刚度仍是提高衬砌抗冻能力的有效措施。