应用综合措施修复斜井

本文介绍了在湖北黄金公司鸡冠咀金矿副斜井的修复工程中,采用井筒浅部地面注浆,锚、网、喷构筑井筒反拱,井筒壁后及围岩注浆等综合措施,使修复工作获得成功。     

偏心受剪螺栓群的极限状态计算方法

螺栓群在偏心剪力作用下会产生附加弯矩.目前常用的设计方法为弹性计算方法,但极限状态计算结果与试验结果更加吻合.通过工程上常用的实例来比较弹性和极限状态两种计算方法的结果.经过大量运算,得出两种方法的规律性变化.     

在拱腰爆炸荷载作用下锚杆动态响应数值分析

为研究拱腰集中装药下锚杆的动载响应特性,利用有限元分析程序LS_DYNA 3D,对锚杆的轴向应力分布规律进行了显示动力分析。对比爆心径向同一距离测点的实测压应力时程曲线,模拟结果曲线峰值、形态和趋势与之较为一致。迎爆侧受压强度明显大于背爆侧,最强的受压部位在迎爆侧拱腰;迎爆侧拱顶和拱腰受拉强度比较大,最强受拉部位在拱顶。受压峰值和受拉峰值从锚头到锚端都是先增加后减小,但最大峰值位置不同,并利用应力波原理和最大拉应力瞬时断裂准则分析其原因。     

螺栓连接件力学特性计算与模态试验对比分析

接触非线性在工程中是广泛存在的,但目前有限元分析软件尚不能完全解决非线性动力学问题。文中针对一螺栓连接件建立不同传力途径的有限元模型,并与试验结果对比分析,得到最佳建模方案,有效削减接触非线性对动力特性的影响,在工程中解决类似问题具有一定借鉴作用。     

Applicability of damage models for failure analysis of threaded bolts

Damage models have been applied in engineering applications. In the present work both Gurson–Tvergaard–Needleman (GTN) model and the progressive damage model have been employed to describe plastic deformation and damage behaviour in the tensile bars and threaded bolts. The predictive capabilities of the models are critically assessed. The parameters in the damage models are identified from uniaxial tensile tests. The models are applied to predict failure of the threaded bolts. Numerical results reveal both models agree with experimental data in uniaxial tension and in threaded bolts. The overall results do not show substantial differences. However, damage evolutions from both damage models display very different developments. Whereas the GTN model confirms damage nucleation in the specimen center of the uniaxial tensile bars, as observed in experiments, the progressive damage model predicts damage starts from the specimen surface where the plastic strain reaches its maximum. In threaded bolts both models do not show significant deviations in predicting the ultimate loading. The progressive damage model without stress triaxiality consideration predicts an unrealistic ductile fracture process and cannot be applied to metallic materials.     

钢框架中钢梁高强螺栓拼接摩擦耗能的试验研究

为了探索将钢框架中的钢梁高强度螺栓拼接节点按照摩擦耗能节点进行设计的可行性,进行了三个试件的循环加载试验。所有试件的梁柱连接都采用焊缝连接,钢梁拼接按照拼接中心处的实际受力设计,翼缘和腹板拼接全部采用10.9级高强螺栓摩擦型连接,螺栓孔采用长圆孔。试验结果表明:三个试件都能够实现拼接中心的摩擦耗能作用,而且梁柱连接焊缝不会提前破坏;所有试件都表现出了良好的耗能性能;但试验也发现了一些值得注意的问题,如在循环加载作用下,拼接节点的承载能力和耗能能力下降较多,长圆孔的开孔长度对节点的转动能力和耗能能力影响较大等。     

内啮合齿轮泵联接螺栓的载荷分析

螺栓组的载荷计算一般认为是各螺栓均分工作压力,但实际上各个螺栓受力可能是不相等的。以内啮合齿轮泵上的螺栓为研究对象,对压力进行合理分区,利用SolidWorks中的Simulation功能来分析螺栓受力情况,然后计算受力最大螺栓的应力。通过此方法可以检验能否采用低精度等级的螺栓以节约生产成本。     

Blind bolted moment connection to sides of hollow section columns

This paper presents the results of an experimental programme for a new blind bolted connection to unfilled hollow section (HS) columns under static loading. In this connection, channels with side plates connect beam flanges to the side face of HS columns. This is a simple alternative connection to typical face connections, i.e. the extended endplate connection or the T-stub connection (with T-stubs connecting the top and bottom flanges of the beam to the face of the column). The channel side plate connection was found to be much stiffer than a typical face connection and has the potential to achieve a rigid connection status for braced frames according to the EC3 classifications. Comparison of the test results and three dimensional finite element (FE) modelling indicates that the FE analyses can be used to predict the connection behaviour with sufficient accuracy. The preliminary investigation for the channel side plate connection shows promising results and forms the basis for the development of other blind bolted side connections for applications in the low rise construction industry.     

钢结构用高强度螺栓预拉力损失研究

利用正交试验,对钢结构用高强度螺栓预拉力损失进行了终拧后时间、螺栓直径、连接板厚度、环境温度四因素三水平影响分析。结果表明：在给定的四个影响因素中,对螺栓预拉力损失率影响由大到小的顺序为终拧后时间、螺栓直径、钢板厚度、温度。同时对两组试件进行了终拧后时间这一因素的长时间监测,得到预拉力损失的变化规律。     

止水帷幕结合土钉及预应力锚杆支护施工应用

针对深基坑开挖施工中,地下水位高、土质条件复杂、基坑降水困难、施工安全隐患多等因素,通过合理设计支护方案、安排施工工序,实现了安全、经济、环保的目标,从而为基础施工提供了较为理想的施工条件。