新梅江大桥挂篮设计及施工

挂篮悬浇应用于桥梁的施工中,具有自重轻,工艺简捷,变形小,工期短、质量高的特点.通过结合新梅江大桥工程挂篮施工技术,阐述了挂篮承重系统、吊挂系统、锚固系统和走行系统等的构造形式,并介绍了挂篮施工及施工过程的质量控制措施.     

48m箱梁节段拼装预应力孔道质量控制技术

红柳河特大桥48m简支箱梁预应力质量控制的关键是节段箱梁预制过程中的预应力孔道位置控制和节段拼装过程中的湿接缝预应力孔道位置控制。由于48m箱梁节段拼装预应力筋过长、弯曲较多都会加大预应力筋的孔道摩阻损失,因此,后张法在张拉前测试预应力孔道的摩阻力是确保施工质量的有效措施。预应力孔道的摩阻测试有效验证了孔道位置施工质量,给预应力张拉提供准确的施工参数,确保预应力张拉施工质量。     

Testing the functionality of peripheral vision in a mixed-methods football field study

ABSTRACT

In team sports, peripheral vision might be useful to simultaneously monitor movements of opponents and teammates. Until now, however, little is known about the perceptual-cognitive processes underlying peripheral vision in a sporting task. Therefore, we used a mixed-methods approach with in-situ decision making (3 vs. 3 situations) and retrospective verbal reports to identify perceptual strategies used for optimal information pick-up in high- and low-skilled football players. Our results show that the use of peripheral vision by central defenders depends on the position of the ball and the position of the direct opponent. Players were shown to either use a pivot strategy, whereby they frequently look at the direct opponent if he is not in the possession of the ball in addition to making saccades to monitor other players, or they employ a more direct strategy, in which gaze is anchored on this location, avoiding saccades and monitoring the other players with peripheral vision. Based on our findings we make recommendations about how these gaze strategies can be further tested in future research and how sports practice can benefit from these results.     

扩孔锚索在软土深基坑中的应用

通过对厦门软土中某深基坑支护实例分析,揭示在软土地区深基坑采用扩孔锚索取代排桩的内支撑,结合坡顶放坡或水泥土搅拌桩支护设计方案的可行性,探讨支护结构周边土体的变形和锚索拉力的发展特性,为今后类似的深基坑维护工程提供借鉴和经验。     

锚杆锚固质量无损检测研究进展

对煤矿用锚杆锚固质量检测技术的国内外研究历史及使用现状进行了回顾和分析,并对现有一些检测技术的优缺点进行了简要分析,并对彻底解决锚杆锚固质量无损检测的技术进行了展望。     

徽杭高速公路泥岩路堑边坡锚杆试验成果分析

徽杭高速公路B标段泥岩路堑边坡广泛采用了节点锚杆框格梁进行边坡防护与加固。为了对节点锚杆的加固效果进行评价,选取了3块地质条件不同的泥岩、泥质岩路堑边坡进行锚杆拉拔试验。文章研究了各泥岩边坡节点锚杆的拉力一位移曲线,并就试验中存在的有关疑点展开讨论,最后对锚杆试验成果的应用及节点锚杆框格梁技术进行了简要评述。     

预应力混凝土路面设计准则研究

对混凝土路面板施加预应力,可显著提高其承载能力,因而相同荷载下板厚可减小.预应力改变了路面板的结构形式,可抵抗更大的冲击、振动和超载.本文讨论了设计预应力混凝土路面的要点,提出了预测预应力路面早期、使用阶段及开裂后压应力的设计步骤.必须清楚区分反复荷载和非反复荷载中的变量,同样需要检查预应力路面在超载下开裂后的恢复情况.文末附一个设计实例说明该方法的应用.,With a concrete pavement slab prestressed, its load-carrying capacity can be significantly increased, thus a thinner slab may be used for the same loading. Prestressing modify the structural behavior of the pavement slab and there is a greater resistance to impact, vibration and overloading. This paper discusses the major design considerations necessary in the successful construction of prestressed concrete pavements and presents a design procedure developed to predict the compressive stress due to prestressing in the pavements at early stage, during service and after cracking. Variation in the approach for repetitive and nonrepetitive loads is clearly distinguished. Check on the recovery after cracking for overloading in prestressed pavements is also needed. Finally, a design example is illustrated the application of the approach developed.     

锚具静载锚固效率实验装置的研制及开发

研制了以空心钢管钢筋混凝土为实验机台座的锚具静载锚固效率实验装置,介绍了该实验数据的采集方法.此试验装置可开展锚具静载锚固效率的教学试验,并多次应用于大跨度预应力桥梁锚具静载锚固效率监测.     

预应力混凝土结构的耐久性设计方法研究

根据预应力混凝土结构的耐久性特点,分别定义了结构构件在碳化环境和氯离子侵蚀环境下的耐久性极限状态,建立了以可靠性数学和随机过程为理论基础的数学模型,并对耐久性失效概率进行了理论分析.提出了碳化环境下的预应力混凝土结构构件的耐久性实用设计方法.计算结果表明:预应力混凝土结构的耐久性优于传统钢筋混凝土结构;现行国家规范(GB 50010-2002)中规定的混凝土保护层厚度是不足的;根据碳化和氯离子侵蚀环境的不同,混凝土保护层厚度应该分别不小于35mm和45mm.     

锚网索支护全煤巷实现综掘机90°转弯连续掘进技术的研究

介绍朱庄煤矿用锚网锚索支护大断面煤巷实现综掘机90°转弯连续掘进技术的研究,并对施工工艺、监测系统、支护参数和经济效益进行分析比较。朱庄煤矿应用的实践表明本项技术可以大大提高掘进速度、降低成本。