公路特大型泥石流灾害控制技术研究

公路特大型泥石流是国内外迄今尚未解决的主要公路病害，具有大冲大淤、冲击路径变化不确定以及毁损作用极其强烈的特性，是公路泥石流研究及防治的核心。本文基于两相流理论建立了泥石流冲击力计算公式；遵循特大型泥石流发育特点及公路泥石流防治特殊要求建构了泥石流综合治理模式，并开发了速流结构、底埋隧道、翼型墩汇流技术及糙桩技术，并对相关的核心技术进行了深入分析。研究成果对于彻底解决公路特大型泥石流病害奠定了重要的技术基础。     

公路隧道防雷接地系统研究

分析了公路隧道防雷接地的特殊性，提出将隧道初期支护的锚杆、管棚、拱架等焊接固连起来多点引出做基础接地体，构成接地装置，并采用拦截、屏蔽、均压(等电位连接)、分流和共用接地系统等综合防雷方案。实践证明，行之有效，对公路隧道防雷接地具有现实意义。     

沿河公路路基冲刷深度的计算

在沿河公路路基冲刷防护中多采用挡土墙或石砌护坡。确定合理的局部冲刷深度 ,是确定挡土墙基础埋置深度的重要依据。在分析路基局部冲刷的影响因素基础上 ,结合甘肃省陇南地区沿河公路挡土墙的冲刷实测结果 ,探讨和建立新的局部冲刷计算公式 ,公式的计算结果与实测数据基本相符     

天巉公路隧道防排水设计研究

以天二级汽车专用公路 9座隧道为依托 ,针对甘肃省境内干旱、半干旱黄土地区的的工程地质和水文地质特点 ,分析了影响隧道防排水结构设计的因素 ,提出天公路隧道三种防排水结构形式和设计图式     

电站600 MW机组P91三通的设计制造

采用压力面积法对电站 6 0 0MW机组主蒸汽管道P91材质三通进行设计 ,应用有限元对设计模型进行验证 ,通过改进常规径向补偿热压工艺 ,成功制造出 6 0 0MW机组P91钢 90°热挤压三通。通过检验和试验 ,表明其可替代进口锻制 6 0 0MW机组P91钢 90°三通。     

空气罐控制输液管道水击研究

采用特征线法对瞬时关闭管道终端阀门 ,在安装和不安装空气罐两种状况时 ,管道压力的变化情况进行了数值模拟 ,并分析了空气罐初始容积、空气罐安装位置等参数对管道瞬态水击压力变化的影响 ,结果表明 :在输液管道的适当位置安装容积一定的空气罐能较好地控制水击的产生     

An Exploration of the Relationship between Timing and Duration of Maintenance Activities

The timing and duration of an activity episode are two important temporal aspects of activity-travel behavior. Understanding the causal relationship between these two variables would be useful in the development of activity-based travel demand modeling systems. This paper investigates the relationship between these two variables by considering two different causal structures – one structure in which time-of-day choice is determined first and influences duration and a second structure in which activity duration is determined first and affects time-of-day choice. These two structures are estimated within a discrete-continuous simultaneous equations framework employing a full-information maximum likelihood methodology that allows error covariance. The estimation is performed separately for commuter and non-commuter samples drawn from a 1996 household travel survey data set from the Tampa Bay area in Florida. The results of the model estimation effort show that the causal structure in which activity duration precedes or affects activity timing (time of day choice) performs better for the non-commuter sample. For the commuter sample, the findings were less conclusive with both causal structures offering equally good statistical measures of fit. In addition, for the commuter sample, all error correlations were found to be zero. These two findings suggest that time of day choice and activity episode duration are only loosely related for the commuter sample, possibly due to the relatively non-discretionary and inflexible work activity and travel.     

成都市城区水域开发工程设计概况

今文介绍了成都市府南河上蓄水、泄洪为一体的水工设施——充水式橡胶坝枢纽工程，并确定了坝址、坝高及坝前所形成的有效水面面积，还讨论了实现城区西侧勾通府南河的设想。     

遗传算法在区段站到发线的应用研究

为解决车站到发线的合理运用问题，采用遗传算建立了到发线运用的染色体结构和适应度函数，对这种复杂的非线性组合优化问题进行了仿真。     

汽车操纵动力学十八自由度模型仿真研究

本文介绍了根据多刚体动力学中的凯恩方法建立的一般两轴汽车的十八自由度数学模型。