华北地区岩质边坡绿化措施及植物选择研究

华北地区大规模的公路、铁路、矿山等工程建设遗留下了大量高陡的岩石边坡,随着经济发展、可持续发展对环境的要求,在一个极度退化的岩质边坡生态系统上,重新建立起一种结构稳定、功能完善、并能自我维持的土壤生态系统,并恢复植物群落多样性仍然是一个艰巨的课题。结合石家庄西部山前区矿山环境恢复治理工程,对该区岩质边坡常见绿化措施的特点、适宜条件及如何选择等作了分析归纳,同时对绿化植物物种的选择原则和适宜的华北地区生长的物种及相关属性进行总结,为该区岩质边坡绿化提供依据。     

毛尔盖水电站烧发河牙窝沟泥石流的成因、预测及防治措施

在现场地质勘察的基础上,分析了毛尔盖水电站烧发河支流牙窝沟泥石流的成因,描述了泥石流沟的特征,运用工程地质分析方法对泥石流沟形成条件进行了定性分析,计算了不同概率下泥石流的峰值流量及总量,对牙窝沟泥石流发展趋势及影响范围进行了预测分析,并在此基础上提出了相应了防治措施。     

某公路顺层边坡失稳影响因素及破坏机制

顺层边坡开挖形成大量岩体结构复杂、稳定性差的边坡,在工程开挖及降雨的影响下,出现不同规模的变形失稳现象,严重影响工程建设和运营期间的安全。通过某公路顺层边坡在施工过程中产生失稳现象的研究,分析了边坡失稳影响因素,探讨了边坡变形破坏模式。     

水泥混凝土路面裂缝产生原因及防治措施

水泥混凝土路面具有强度高、稳定性好、耐久性强、使用寿命长等特点,在公路建设中得到广泛应用。但由于施工中控制不当,或受环境作用影响,混凝土路面结构出现裂缝,从而影响它的使用功能,缩短了使用寿命。文章以内蒙古一条公路项目为例,详细阐述了混凝土路面裂缝产生的种类、原因及防治措施。     

降雨型滑坡失稳机理及稳定性评价方法研究进展

为了深化对降雨型滑坡的认识,梳理了有关降雨型滑坡失稳机理和稳定性分析的研究现状,在此基础上,对于未来重点研究方向进行了展望。首先,概括降雨型滑坡的主要类型、特征以及控制因素,重点论述了浅层土质滑坡2种失稳机理,即由基质吸力控制的较深层滑坡和渗透力占主导作用的较浅层滑坡。然后,介绍相关入渗概念和入渗模型,重点介绍了以Green-Ampt入渗模型为基础的一些改进模型,简要阐述了降雨作用下岩质滑坡的稳定性分析方法,之后重点论述了基于非饱和土力学和极限平衡法的土质滑坡稳定性分析方法,选择常见的稳定性分析方法应用于实践中,并通过安全系数的相互比较以增进其本质的理解。最后,分别从研究方法、研究对象以及研究成果运用3个方面剖析了已有失稳机理和稳定性评价研究的不足,并对相关研究方法的适宜性、研究对象的重要性以及研究成果运用的前瞻性进行探讨,在此基础上认为未来的研究应重视现场调查和监测技术的应用、综合运用多种研究方法、跨学科进行综合分析、考虑降雨入渗及稳定性分析的不确定性,以及注重高新技术的运用。     

Revisiting the notion of induced traffic through a matched-pairs study

In investigating the question of the existence of "induced demand" in connection with highway expansion projects, Hansen et al. (1993) studied eighteen California state highway segments whose capacities had been improved in the early 1970s. For the present study, these segments were paired with control segments that matched the improved segments to unimproved ones with regard to facility type, region, approximate size, and initial volumes and congestion levels. Taking annual data for average daily traffic (ADT) and design-hour-traffic-to-capacity (DTC) ratios during the 21 years 1976–1996, three approaches were used to compare growth rates between the improved and unimproved segments: overall growth comparisons for the matched pairs, repeated measures analysis, and analysis of matched mean profiles. We found the growth rates between the two types of segments to be statistically and practically indistinguishable, suggesting that the capacity expansions, in and of themselves, had a negligible effect on traffic growth over the period studied. Reasons for the differences between these results and those of aggregate cross-sectional models finding a significant induced demand effect are discussed. Our analyses suggest that the aggregate models may overestimate induced traffic due to the attribution of at least a fraction of the observed traffic growth to "induced demand" rather than to some of the confounding factors which were not controlled for in such studies. At the same time, it is noted that the traffic induced by capacity expansion may in certain circumstances be larger than that observed in the present study, with the effect of new highway construction on traffic growth being a prime candidate for scrutiny in this regard. The results of this study nonetheless suggest that, for existing facilities, the size of the induced-traffic effect that can be attributed to capacity enhancements may be sufficiently small that its detection in a case-control study would be difficult, if not impossible, without a substantially larger sample size.     

高速公路建设与建设环境

就高速公路建设与建设环境的关系进行了阐述，并对建设环境方面存在的主要问题进行了分析，就优化建设环境的对策进行了一些探讨。     

开阳高速公路沥青混凝土路面平整度的控制实践

通过介绍施工阶段影响沥青混凝土路面平整度的诸因素及平整度的控制措施 ,为改善和提高沥青混凝土路面平整度提供一些借鉴经验。     

基于正交异性壳单元的悬索桥非线性静风稳定性分析

基于正交各向异性空间壳单元的大跨度桥梁静风稳定分析方法,通过对江阴长江大桥的静风稳定分析表明,大跨度悬索桥在静风荷载作用下存在两种破坏形式,即静力扭转发散与风荷载超过结构极限承载力造成的破坏,结构的具体破坏形式可能因攻角不同而改变。通过与空间梁单元模型的比较分析表明:两种方法计算的整体变形比较一致,但传统空间梁单元模型存在一定的局限性,而壳单元法能比较全面地考虑结构的整体与局部失稳。     

沥青路面早期损坏的原因及防治

该文通过济宁市路网建设的实例,提出了沥青路面早期损坏的类型与特征,分析了存在问题和原因,给出了解决问题的方法和措施。