矩形顶管施工地下管线破坏机理分析与控制

由于顶管施工不可避免地对周围土体产生扰动,引起地层移动,从而威胁邻近地下管线的安全.文中以某地铁站出口市政过街通道矩形顶管施工为背景,通过分析矩形顶管施工时土体与地下管线的相互作用,探讨管线应力和位移的分布情况,对其破坏机理进行了总结,并阐述了相应的控制措施.     

超声波检测钢管芯框架柱混凝土质量

以钢管混凝土超声检测技术为基础,结合工程实例,阐述钢管芯混凝土质量超声检测的基本原理和方法。     

PEIOO-RC管道专用料的发展及国内应用情况

本文简要介绍了聚乙烯（PE）压力管道材料的发展、耐开裂聚乙烯（PEl00一RC）材料的定义,PE压力管道混配料质量性能及要求,特别是PEl00一RC的关键技术要求、应用经济性能比较及绿色环境效益,还介绍了PEl00一RC管道在国内的应用情况。     

重庆地区旋挖桩施工质量问题浅析及解决对策

重庆市城乡建委组织重庆市质量监督总站,重庆市建筑科学研究院等单位编制的《旋挖成孔灌注桩工程技术规程》已经在住房和城乡建设部备案,于2012年12月27日发布,2013年3月1日起施行。为了确保旋挖成孔的施工质量,加强施工管理与技术学习,该文对重庆地区旋挖成孔桩普遍存在的问题进行了分析,并提出了解决的方案。     

Hysteresis loops of carbon fiber-reinforced ceramic-matrix composites with different fiber preforms

The hysteresis loops of C/SiC ceramic-matrix composites (CMCs) with different fiber preforms, i.e., unidirectional, cross-ply, 2D and 2.5D woven, 3D braided, and 3D needled at room temperature have been investigated. Based on fiber slipping mechanisms, the hysteresis loops models considering different interface slip cases have been developed. The effects of fiber volume fraction, matrix cracking density, interface shear stress, interface debonded energy, and fibers failure on hysteresis loops, hysteresis dissipated energy, hysteresis width, and hysteresis modulus have been analyzed. An effective coefficient of fiber volume fraction along the loading direction (ECFL) was introduced to describe fiber preforms. The hysteresis loops, hysteresis dissipated energy and hysteresis modulus of unidirectional, cross-ply, 2D and 2.5D woven, 3D braided and 3D needled C/SiC composites have been predicted.     

Avoiding filter cake cracking: Influence of consolidation on desaturation characteristics

In cake filtration processes with an air-blowing step, cracking is an undesirable phenomenon as it leads to deterioration of the filtration process by highly increasing gas throughput. This leads to higher residual moisture if the pressure difference cannot be maintained and an increase in overall cost. Crack formation can be avoided by compacting the filter cake before desaturation. While this action will make the separation process applicable by highly reducing gas consumption, there are also potential negative effects. Compaction increases filter cake resistance and might therefore slow down desaturation kinetics. Therefore, the authors investigated how the filter cake characteristics governing desaturation change from the nonconsolidated to the consolidated state of the filter cake and compared these findings to the actual dewatering kinetics. The results showed that for the case where cracking could be oppressed, dewatering kinetics of the consolidated cake are actually faster than for the nonconsolidated cake, despite higher resistance of the consolidated cake. Thus, compaction is an appropriate action when dealing with filter cake cracking.     

荷载作用下埋地玻璃钢夹砂管受力特征分析

就埋地玻璃钢夹砂管在荷载作用下的受力特征问题,进行室内模拟试验与分析,试验采集了不同试验工况下埋地管道不同部位应力应变、管周不同位置土压力以及变形特征,得出了管道在不同荷载作用下的管土相互作用规律,从而判断埋地管道关键部位受力性状,并可为荷载作用下埋地玻璃钢夹砂管涵设计提供科学依据。     

600kt/a NPK复合肥AZF工艺特点浅析

介绍中国-阿拉伯化肥有限公司采用AZF工艺生产600 kt/a NPK复合肥的工艺流程,分析该工艺在造粒、干燥、筛分破碎、冷却包裹、气体除尘以及尾气洗涤等各工序的特点。采用AZF工艺生产NPK复合肥能保证产品呈中性、质量稳定、溶解性好、颗粒强度高、水分低、结块轻、肥效高;同时车间粉尘少,操作环境好,排放尾气中有害成分低,环境污染小。     

高温环境下催化裂化催化剂磨损状况的研究

为研究流化催化裂化(FCC)催化剂在高温环境下的磨损行为,在一套固定流化床装置中考察了FCC平衡剂CGP-I在500℃和600℃高温环境下磨损率的时变关系和过孔气速对磨损率的影响,分别从颗粒形貌、磨损动力学等方面对催化剂的磨损机制进行了研究。结果表明:随着磨损时间的延长,磨损速率逐渐下降;随着磨损温度和孔气速的增加,磨损率增大。通过分析结果并与Gwyn磨损动力学方程比较建立了宏观磨损平衡方程,整个磨损过程可近似看作一级不可逆过程,该催化剂磨损率随磨损时间和孔气速的升高呈指数关系增加,高温环境下催化剂的磨损行为主要受表层磨损机制支配。     

沉降罐加气浮技术处理含聚污水的现场试验研究

为了提高油田含聚污水的处理效果,对污水站已建的沉降罐进行了改造。通过在自然沉降罐前增加管式反应器和在内部设置穿孔布气管,进行管式反应器单独气浮、穿孔布气管单独气浮及管式反应器和穿孔布气管同时气浮3种方式处理含油污水的现场试验。试验结果表明,与不加气浮自然沉降罐相比,3种气浮方式油的去除率都提高23%以上,SS去除率都提高了19%以上,并确定了合理的回流量。