Simplified analysis for estimation of the behavior of a submerged floating tunnel in waves and experimental verification

To achieve rational design in waves for a submerged floating tunnel which has emerged as a new offshore transportation infrastructure, it's necessary to understand its hydrodynamic behavior. For simple but accurate estimation of hydrodynamic forces, a theoretical method is proposed and the tests with physical models in a wave flume were carried out for verification. Morison's equation was used to estimate wave loads composed of inertia force and drag force. Forces calculated by applying the linear wave theory to Morison's equation coincided well with those measured by the tests. The test results showed that mooring systems played a significant role in the movement of the submerged floating tunnel in waves. A pendulum model could be used to describe the motion of the submerged floating tunnel with a single vertical mooring. Based on the verified relations, a simple slack condition which causes the submerged floating tunnel to be unstable was also proposed. The simplified approach proposed by this study proved to be useful in designing the submerged floating tunnel in the initial stage.     

高速铁路路基质量检测指标K30、Ev2、Evd的相关性分析

高速铁路施工中同时采用了K30、Ev2、Evd3项力学指标对路基压实质量进行检测,该3项指标的检测内容与检测原理接近.为了减少检测工作量、提高检测效率,本文在简要分析3项指标各自测试原理的基础上,利用大量实测数据,对3项指标进行了相关性分析.分析结果表明,3项指标具有较好的相关性,且用回归分析结果反算的数值与规范给出的标准相近,说明该3项指标具有较好的相互替代性.依据分析结果,认为用Ev2替代K30,或用Evd替代Ev2和K30都是可行的.     

空管运行效率评估指标体系研究

空管运行效率是衡量一个区域空管系统总体运行状态的综合指标,它受到很多与空管系统有关因素的影响。基于人机环系统工程理论,结合空管运行实际情况,充分分析空管运行效率的影响因素,建立空管运行效率评估的原则、标准和指标体系。     

沥青混合料低温性能评价指标研究

通过对现有评价沥青混合料低温性能的试验方法和评价指标的对比,提出低温弯曲和弯曲蠕变试验是较为经济可行的试验方法。破坏能是较好的评价沥青混合料低温性能的指标。应用低温弯曲和弯曲蠕变试验所得数据,给出了破坏能的简单计算方法。     

基于灰色聚类分析的城市交通路网综合评价方法研究

针对城市交通路网的多指标综合评价中存在的主观性等问题,依据灰色聚类分析原理,提供了一种计算各指标权重的方法,使得指标之间的权重在评价过程中自动产生,不需要经过人为判断,减少了评价过程中的主观因素。在此基础上,结合杭州市萧山区城市路网进行综合评价,并根据评价过程与结果,提出路网改善建议。     

Sediment physical properties of the DYNAS study area

Physical properties of the deposits in the DYNAS study area, the Mecklenburg Bay, were investigated using sediment echosounders and laboratory analysis were carried out on undisturbed short sediment cores. Wet bulk densities of about 1.2 g/cm³ for mud and up to 1.9 g/cm³ for silty sand were found in surface sediments of the Mecklenburg Bay. Sediment density–depth functions were approximated by logarithmic regression functions at different depth intervals. Sediment consolidation was studied by both (i) consolidation tests of sediment samples and (ii) from the void ratio–overburden pressure relation in natural sediments. Low shear strength values of 9–71 Pa were measured at the mud surface. Downcore, a depth gradient of about 14.5 Pa/cm was calculated. Sediments with high silt and sand contents are characterized by shear strength values of up to 3000 Pa. Published formulas derived from erosion studies were used to calculate the critical shear stress using wet bulk density and shear strength. The obtained results demonstrate clearly, that there is still a wide gap in knowledge about the relationships between erosion parameters and sediment physical properties.     

透水砼结构特点及其透水性能研究

就功能而言,透水砼与普通砼相比较,最大的区别就是其良好的透水性能.本文分析了透水砼的结构特点、透水指标及其影响因素,通过试验确定了透水砼的透水系数,建立了透水性能与孔隙率、透水系数与力学强度之间的关系,目的是为透水砼配合比设计提供参考依据并指导透水砼路面的结构设计.     

客运专线引入枢纽后客运站合理布局的探讨

通过分析影响专线客运站布局的诸因素，根据其对枢纽的影响程度的大小．制定一套合理的指标体系，研究指标量化的方法和分析指标权重，将方案中的所有指标进行总体比较。选择出最优方案。     

大体积混凝土冬期施工控制

控制大体积混凝土冬期施工裂缝的关键是混凝土配合比设计和根据工程实际情况采取的温控措施。     

船舶电站物理模拟系统的研究

以相似理论为基础，提出用直流电动机调速系统模拟船用柴油机调速系统，对船舶电站物理模拟系统进行了计算机仿真，证明本文提出了的物理模型和数学模型是合理的，可行的，达到了用直流电动机模拟柴油机的效果。