纵向钢筋对矩形混凝土轴心受压柱延性的影响

许多实验数据显示，纵向钢筋对钢筋混凝土轴心受压柱的延性有很大影响，保证纵向钢筋在受力过程中不提前失稳是问题的关键。在合理布置箍筋的前提下，增加纵向钢筋数量可改善混凝土延性；通过控制纵向钢筋与箍筋比例及钢筋在柱子中的承载力份额可以获得预期的延性指标。     

水平井气液两相变质量流的流动规律研究

水平井井筒变质量流的流动规律是进行水平井产能预测、油井生产系统优化设计及动态分析的基础。从理论和实验两方面对水平井筒气液两相变质量流的流型判别与压降计算进行了探索性研究 ,建立了分层流、间歇流、分散泡状流和环雾流的流型判别模型以及分层流与间歇流的压降计算模型 ,并绘制了流型图。计算值与实验数据对比表明 ,分层流和间歇流模型与以空气和水为介质的实验结果具有良好的一致性 ,其压力梯度模型的计算值与实验测量值间的平均相对误差为 5 .3% ,大部分误差在 10 %以内 ,说明该计算模型有较高的精度     

泵送混凝土剪力墙裂缝成因分析及治理方案

介绍高层建筑结构剪力墙长度大于 6m将产生竖向裂缝的成因 ,并在建筑构造设计方面提出若干改进方案     

双梁门式起重机水平刚度的计算

本文对起重机水平刚度的指标计算实行空间分析,充分考虑门式箱形空间结构中的广义约束力作用和刚度匹配影响,保证结构变形的连续性和协调性,对传统计算方法进行改进,提出新的实用计算公式,从而提高了对门式起重机水平刚度评价的真实度。     

小桥涵预制板改现浇的施工方法

文章从荷载横向分布机理,阐述如何将预制板梁改成现浇板梁,并提出了“预制工现浇”法。     

竖向弹簧-钢球隔震系统的隔离水平地震作用

提出一种新的竖向弹簧—钢球隔震系统隔离水平地震作用的隔震方法,用势能不变值原理与“对号入座”法则建立该隔震系统的振动方程,分析各控制参数对该隔震系统地震反应的影响．研究结果表明,该隔震系统结构简单,隔离水平地震作用效果显著．     

Research on spatial association rules mining in two-direction

In data mining from transaction DB, the relationships between the attributes have been focused, but the relationships between the tuples have not been taken into account. In spatial database, there are relationships between the attributes and the tuples, and most of the associations occur between the tuples, such as adjacent, intersection, overlap and other topological relationships. So the tasks of spatial data association rules mining include mining the relationships between attributes of spatial objects, which are called as vertical direction DM, and the relationships between the tuples, which are called as horizontal direction DM. This paper analyzes the storage models of spatial data, uses for reference the technologies of data mining in transaction DB, defines the spatial data association rule, including vertical direction association rule, horizontal direction association rule and two-direction association rule, discusses the measurement of spatial association rule interestingness, and puts forward the work flows of spatial association rule data mining. During two-direction spatial association rules mining, an algorithm is proposed to get non-spatial itemsets. By virtue of spatial analysis, the spatial relations were transferred into non-spatial associations and the non-spatial itemsets were gotten. Based on the non-spatial itemsets, the Apriori algorithm or other algorithms could be used to get the frequent itemsets and then the spatial association rules come into being. Using spatial DB, the spatial association rules were gotten to validate the algorithm, and the test results show that this algorithm is efficient and can mine the interesting spatial rules.     

方钢管混凝土柱节点的抗剪受力分析

为研究方钢管混凝土柱节点的受剪屈服问题,建立了方钢管混凝土柱节点抗剪受力模型。该模型在试验的基础上,将方钢管混凝土柱节点抗剪受力过程分为协同工作、共同工作、屈服强化和极限变形4个阶段,抗剪受力由钢管腹板和节点核心区混凝土共同承担,其中核心区混凝土又以平面抗剪和压杆模式分别对抗剪承载力作出贡献。综合考虑这三者的作用,该模型与试验结果吻合较好。使用该模型可对方钢管混凝土柱节点的受剪和变形等性能进行分析研究。     

碎石桩加固土质边坡的机理及稳定性评价

云南省华电镇雄电厂边坡的工程地质条件复杂,软弱夹层较多,地基土体基本处于饱和状态,抗剪强度较低.由于以上的工程实际,设计采取碾压堆石压坡的工程措施,局部辅以振冲碎石桩置换,以期对坡体的受力、变形和稳定性等进行改善.利用FLAC3D软件对镇雄边坡的碎石桩加固过程及碾压堆石压坡填土过程进行了三维数值仿真分析,并分析了碎石桩加固土质边坡的机理.考虑复杂地基与碎石桩、挡土墙之间的相互作用,以及碎石桩加固后的排水情况,采用分级加载的方式模拟边坡的填土过程,通过坡体的应力、位移对比,定量分析了碎石桩加固措施的效果.基于强度折减法,采用结点位移法评价边坡的稳定安全状况.计算结果表明,采用碎石桩加固并进行排水后,提高了土体材料的力学性质,减小了孔隙水压力,边坡的受力得到了较大的改善,变形得到了控制,边坡的稳定性较好.