Deformation mechanism of high-stress and broken-expansion surrounding rock and supporting optimization based on the gray correlation theory

Aiming at the large deformation and support problems of high-stress and broken-expansion surrounding rock, and taking 1 000 m level roadway of Mine II in Jinchuan as the research object, an investigation on the deformation and damage of roadway surrounding rock and an analysis of its mechanism were carried out. The gray correlation theory was used in support scheme optimization design. First, causes and mechanism of deformation of the 1 000 m horizontal transport channel were analyzed through field investigation, laboratory test and data processing methods. We arguued that poor engineering geological conditions and deep pressure increases were the main factors, and the deformation mechanism was mainly the ground deformation pressure. Second, the gray correlation theory was used to construct supporting optimization decision method in the deep roadway. This method more comprehensively considers various factors, including construction, costs, and supporting material functions. The combined support with pre-stressed anchor cables, shotcrete layer, bolt and metal net was put forward according to the actual roadway engineering characteristics. Finally, 4 support schemes were put forward for new roadways. The gray relational theory was applied to optimizing the supporting method, undertaking technical and economic comparison to obtain the correlation degree, and accordingly the schemes were evaluated. It was concluded as follows： the best was the flexible retaining scheme using the steel strand anchor; the second best was the one using plate anchors on the top and rigid common screw steel bolt on the two sides; the ttiird was; the rigid common screw steel bolt in full section of roadway; and the worst is the planished steel rigid support. The optimized scheme was applied to the 1000 m level of new excavation roadway. The results show that the roadway surrounding rock can reach a stable state after 5 to 6 months monitoring, with a convergence rate less than 1 mm/d.     

连续箱梁桥拓宽拼接方式的分析

基于高速公路上混凝土连续箱梁桥的不同特点,结合拓宽工程实践,总结了现有刚接及铰接方式的适用范围及具体构造,然后针对错孔布置桥梁拼接受力复杂、三向预应力箱梁拼接不能破坏横向预应力以及大跨径桥梁拼接等工程难题,提出了箱梁间不连接或弱连接的构造设想,以期对同类工程有参考价值。     

干摩擦和水润滑条件下等静压石墨和碳石墨摩擦学性能的对比研究(英文)

研究了等静压石墨和碳石墨在干摩擦和水润滑条件下的摩擦学性能.采用销-盘摩擦磨损试验机进行等静压石墨和碳石墨的摩擦学实验.通过摩擦系数和磨损率来评估两类材料的摩擦学性能,通过磨损形貌来分析其磨损机理.实验结果表明,在干摩擦条件下,等静压石墨的摩擦系数大于碳石墨的摩擦系数,而等静压石墨的磨损率低于碳石墨的磨损率.在水润滑条件下,等静压石墨的摩擦系数和磨损率明显降低.等静压石墨的磨损形式主要是磨粒磨损,碳石墨的磨损形式主要是剥落磨损.最后,系统地分析了等静压石墨在干摩擦和水润滑条件下的磨损机理.     

结构体系转换顺序对大跨连续梁桥施工控制的影响研究

利用桥梁结构分析软件MIDAS／Civil建立桥梁结构计算模型，对莱在建特大跨悬臂浇筑预应力混凝土连续梁桥的整个施工过程进行仿真分析，同时运用前进分析法对桥梁结构进行施工控制分析计算，重点对结构体系转换过程中临时固结拆除引起悬臂端挠度过大以及由于跨中底板预应力筋引起的张拉后底板压应力过大等问题进行了深入研究，提出通过优化结构体系转换顺序的方法解决以上问题。优化方案的验算结果符合设计规范要求，建议已被采纳。     

静压桩与天津滨海新区土体滑动摩擦的试验研究

静压桩贯入地基时,桩侧面与土之间会产生滑动摩擦.采用改进直剪仪进行试验,研究了静压桩与天津滨海新区土体间的滑动摩擦及其时效性,得出了静压桩与土的外摩擦角及其变化规律,并总结了静压桩与土摩阻力的时效性机理.研究发现滑动摩阻力与土的类型、法向应力有关,且与法向应力近似呈直线关系;随着时间的增长,粘土和淤泥质土与桩之间的摩阻...     

武汉某预应力钢筋混凝土立交匝道荷载试验研究

介绍武汉某预应力钢筋混凝土立交匝道静、动荷载试验内容、检测方法,通过预应力钢筋混凝土立交匝道进行试验分析,对桥梁结构的承载能力和工作状况做出综合评价,确保该桥能安全使用.     

预应力碳纤维布加固技术

本文对现有的碳纤维加固技术进行了介绍,探讨了碳纤维增强塑料加固混凝土结构的优势与缺陷,综述了碳纤维布增强塑料施加预应力后,对加固受弯构件的开裂荷载,极限荷载,抗弯刚度等性能的影响。     

工程静压桩桩端扩张压力评价

为研究工程桩端扩张压力,对现有计算方法进行了改进。文章根据静压桩贯入机理,分析了静压桩的贯桩过程;并在模拟桩体贯入过程的基础上,建立了基于半无限圆孔扩张的压桩静力平衡方程,求得了弹性条件下桩端扩张压力的理论解答,同时进一步分析了桩端扩张压力与压入深度的关系。     

浅谈预应力砼现浇连续箱梁施工技术

结合金山大道快速干道立交桥的工程概况,从地基处理、支架搭设与预压、模板、支座安装、钢筋与波纹管制作与安装、砼浇筑与养护、模板与支架拆除、张拉钢绞线、真空灌浆与封锚、卸落支架等方面就预应力砼现浇连续箱梁的施工工艺作了阐述,并总结了现浇箱梁施工控制要点,为类似条件的工程施工提供了借鉴.     

浅谈边坡支护中预应力锚索施工技术分析

随着我国的快速发展,高等级公路的建设量处在一个逐年攀升的阶段,由于其正在大量建设的过程中,使得公路边坡问题愈发显现出来,预应力锚索施工技术由于其自身的优越性,能够有效地被应用在公路边坡支护领域