Hydraulic Joint for Pipe Jacking

A newly developed hydraulic joint for pipe jacking is described and compared with conventional compression rings. It is shown that with the hydraulic joint, thrust eccentricities are largely reduced, resulting in a much more uniform stress profile at the pipe ends and hence a considerably reduced pipe damage potential. Higher jacking forces can be applied (fewer or no intermediate jacking stations are necessary), longer pipes can be used (fewer joints are necessary), smaller radii of curvature are feasible (fewer or no intermediate jacking pits are necessary) and frictional forces are reduced. The measurement of joint displacements and joint liquid pressures permits an effective real-time monitoring of the jacking process. 30 of the 40 pipelines with a total length of 8.2?km completed so far had curved alignments. The smallest radius of curvature was 86?m using 3?m long pipes with an internal diameter of 1.2?m. Practical experiences gained with the hydraulic joint are summarized.     

复合曲线上点的坐标计算与放样

在道路和建筑物建设等过程中常常设计一些曲线,为了满足不同用途的需要,曲线的形式也不相同,在一个工程项目中有的曲线是由几条不同半径或曲率的线段组成,这样给曲线上点的坐标计算和放样带来不便,特别是在城市建设过程中,施工场地的限制。本文根据工程实例介绍了某个体育场施工中复合曲线上钻孔坐标的计算及测设方法。该方法适合于场地狭小,使用全站仪或测距仪配合计算器进行放样的工程。     

三山岛金矿新立主混合井快速掘砌技术研究

介绍了三山岛新立主混合井连续6 个月（含马头门）掘砌破百米的应用技术,以及各种机械无缝配合和滚班作业施工组织在竖井掘砌中的综合使用,在岩石硬度系数f＞10 以上的竖井开拓中取得了优秀成果。     

铝薄带快速铸轧技术研究

常规连续铸轧工艺存在铸轧速度低、生产率不高的问题.为此,华北铝业有限公司、中南大学和涿神公司合作开发研制了中国第一台超薄快速铸轧机,于2001年12月至2006年进行了多次工业试验,成功地生产出厚度为3.0 mm的铝箔毛料,最大铸轧速度达到4.7 m/min,产能提高了20%,并生产出合格的0.007mm铝箔.这些试验对今后的工业生产有一定指导意义.     

马钢达涅利高质量圆坯连铸机

介绍了马钢全新的达涅利先进12 m半径2流大圆坯连铸机.达涅利拥有的工艺诀窍和生产设备的可靠性保证了其成功投产并给马钢提供了为用户服务的有效工具.圆坯的产量和质量指标达到设计值,意味着达涅利的技术能保证圆坯浇铸管理简便,可在每个工艺阶段对连铸机进行全面控制.     

炼轧厂罗可普连铸机的技术改造和工艺优化

韶钢炼轧厂四机四流罗可普连铸机从意大利德兴公司引进,是目前国内较高拉速小方坯连铸机,最大拉速可达3.60 m/min,平均拉速达3.3 m/min.该连铸机自2000年12月投产,由于该连铸设计主要生产螺纹钢,在品种钢开发过程中,铸坯质量难以达到要求.为了满足品种钢开发的要求,2005年7月对该连铸机进行技术改造和工艺优化.     

板坯结晶器内流场作用下钢液传热凝固的数值模拟

以钢厂230 mm×2 150 mm板坯连铸机为研究对象,通过三维数值模拟分析了拉坯速度(0.8～2.3m/min)、水口浸入深度(100～200 mm)、铸坯宽度(1 100～2 150 mm)对结晶器内流场作用下的钢液传热、凝固特征的影响。结果表明,拉坯速度等参数变化不会改变结晶器内钢液流动的基本特征,但会显著影响到结晶器内窄边坯壳的发育状况。水口浸深、铸坯宽度和拉坯速度的变化对于结晶器熔池液面钢水过热度也有不同程度影响:小断面,大拉速和水口浸入深度较小时熔池液面过热度较大,最大达6.2 K。     

Setting and realizing process plan for straightening thin- walled tube by multiple cross rolls of equal curvature

Since it was difficult to setting the plan and the unifying curvature- radius precisely when the thin- walled tubes were straightened continuously by the rolls of equal curvature. Therefore, based on the mechanism of unifying- straightening for the multiple cross- rolls straightening machine, the judgment method of the unifying curvature- radius was presented firstly in view of the bending and springback equation of the thin- walled tube, and then the searching method of the minimum unifying curvature- radius was presented subsequently, finally the straightening plans were drawn up for different thin- walled tubes with different initial curvature radii, especially for the thin- walled tube with the large initial deformation which could not be unified by the two cross rolls, the new method was pre- bending, unifying, and straightening, and it was also presented whether a thin- walled tube could be straightened. Some procedures were developed by VB to calculate the example, which is shown that the methods are effective, meanwhile it is found that if the unifying curvature- radius exist for an initial curvature- radius, it will not be sole and will be within a scope, and it is also found that there must be a scope of the initial curvature- radius within which the thin- walled tubes can??t be unified by the two cross rolls.     

同步顶升液压系统设计及动态特性分析

In this paper, according to the characteristics of large load and uneven distribution of upper wall, large jacking height and high requirements for synchronous jacking precision in the separation process of the upper and lower wall of WK-35 electric excavator,a large-scale mining equipment in the mine, a hydraulic synchronous jacking method with four-point uneven load is proposed, which combines with the fuzzy PID control method which is suitable for nonlinear and time-varying complex system control to realize the synchronous jacking of excavator. Based on the synchronous jacking hydraulic system of WK-35 electric excavator, a simulation model of AMESim hydraulic system is built for dynamic simulation. The analysis results show that the changes of different loads only affected the piston velocity or oil velocity of the hydraulic cylinder in the final stable state. Both the balance control valve and the throttle speed control valve can quickly reach the stable state within 0~1s, which is conducive to better response performance when the hydraulic system enters the steady state.     

矿热炉自焙电极三维仿真计算及焙烧参数分析

以某矿热炉自焙电极为原型,采用多物理场耦合的方法研究自焙电极温度、电流密度和焦耳热分布。为进一步分析电流、筋片长度、筋片数量和电极糊电导率对自焙电极温度分布影响,绘制接触元件部位z=-0.725 m、z=-0.362 5 m和z=0 m截面温度沿x轴分布曲线。研究表明,自焙电极以400 mm/d的速度压放,焙烧区位于接触元件2/3处时,自焙电极强度能够支撑自身重量,不会发生流糊和软断事故;电流为25、55和100 kA时,随着电流增大,电极焙烧区向接触元件上部移动,电极糊电导率取0.5、1.0和2.0倍时,随着电导率的增大,电极焙烧区向接触元件下部移动;而筋片长度和筋片数量对自焙电极温度场影响较小,筋片长度增减100 mm或筋片数量增减2个,焙烧区变化不明显。     

平面弯曲带式输送机的设计选型及应用

平面弯曲带式输送机运送物料的基本原理是将水平转弯段输送带的内曲线抬高,同时将两侧托辊前倾安装,以平衡输送带张力的分力与离心力。根据物料输送要求,结合现场实际情况,综合考虑运量及成本等,确定输送机的主要参数：带宽1200mm,带速1.6m/s,运输量800t/h,弯曲段曲率半径500m,提升高度10.95m,电机功率250kW。同时确定了输送机转弯处的托辊变位、可变槽角和内曲线抬高角。应用后,输送机运行良好,各项性能指标与设计值基本吻合。     

连铸参数对中间包内控流元件冶金性能的影响

根据相似原理,以浇铸Φ380 mm铸坯的28 t 3流T型中间包为原型,通过实验相似比λ=1:2水模型,研究了拉速0.3～0.9 m/min、液位600～1200 mm连铸条件下,控流元件对中间包内流场特性的影响。结果表明,当实际生产的中间包液位为500 mm左右时,拉速<0.4 m/min时,控流元件改善其流场的作用不明显,不需加入控流元件;当拉速≥0.4 m/min和<0.7 m/min时,可选用带挡墙结构的中间包;当拉速≥0.7 m/min,可考虑挡墙加湍流抑制器的结构,以优化中间包内流场特性。通过对中间包内流场的分析得出,设置控流元件时,应尽量降低注流混乱度并使钢水湍动能尽可能多的消耗在浇铸区。     

Improving the plasticity of hard-to-work tool steel in continuous casting

Pulsed-continuous melt solidification is developed for the production of chill-cast ingots and continuous-cast billets of hard-to-work P6M5 steel. The introduction of pulsed-continuous melt solidification and linear-solidification heat treatment at OAO MMZ Serp i Molot has permitted the continuous casting of high-speed P6M5 steel on a radial machine (radius of curvature 9 m). The new method produces continuous-cast billets of increased plasticity, thereby eliminating the need for forging. The new system has been used to produce hot- and cold-rolled P6M5 steel sheet and bar.     

0.8 m/min拉速H异型坯中间包控流装置对传递性能影响的数值模拟

根据长8 m,钢水液位0.8 m的3流H型连铸坯中间包,采用FLUENT软件建立三维几何模型模拟研究了弧形挡墙导流孔直径D（100~200 mm）,导流孔高度H（350~550 mm）和两导流孔夹角θ（20°~50°）对中间包内钢液的流场和温度场分布、钢液的混合状况及不同粒径夹杂物上浮去除的影响,结果表明导流孔直径D 100 mm、导流孔高度H 550 mm、导流孔夹角θ 50°时,中问包综合传递性能最优,各流平均停留时间差和各出口钢水温度差较小,大颗粒夹杂去除率达76%。     

宜春钽铌矿选矿自动化设计与实践

随着市场竞争加剧以及矿产资源的日益减少,如何提高资源利用率成为我国矿山企业面临的问题。为了提高生产效率,提升资源利用率,越来越多的矿山企业通过完善技术,实现生产过程的自动化和信息化,达到节能增效,提高企业竞争力目的。本文以宜春钽铌矿钟家市选矿厂的选矿自动化系统建设为例,阐述了选矿自动化系统的设计方案与实践内容。     

Laparoscopic visual field. Voice vs foot pedal interfaces for control of the AESOP robot

BACKGROUND: In order for robotic devices to be introduced successfully into surgical practice, the development of transparent surgeon/machine interfaces is critical. METHODS: This study evaluated the standard foot pedal for the AESOP robot compared to a voice control interface. Speed, accuracy, learning curves, durability of learning at 2 weeks, and operator-interface failures were analyzed in an ex vivo model. RESULTS: Foot control was faster and had less operator-interface failures. Voice control was more accurate as measured by "pass points." The foot control learning curve reached a plateau at the third trial, while the voice control did not fully plateau. Durability of learning favored the foot control but was not significantly different. CONCLUSIONS: Currently, the voice control is more accurate and has the advantage of not requiring the surgeon to look away from the operative field. However, it is slower and may require more attention as an interface. As voice recognition software continues to advance, speed and transparency are anticipated to improve.     

脱磷专用转炉的氧枪设计及研究

 脱磷专用转炉通常采用脱磷氧枪促进化渣,提高脱磷率,实现铁水预脱磷。设计了马赫数为1.9、氧枪流量为14500m3/h的4孔脱磷氧枪,利用Fluent软件模拟了脱磷氧枪的速度场、温度场和密度场等分布。模拟发现：4孔脱磷氧枪在枪位为1.5m时,射流速度约为115m/s,当射流速度为100m/s时,最大射流半径为0.28m。在此基础上,将脱磷氧枪用于120t脱磷专用转炉的生产过程,取得了良好的冶炼效果：可控制脱磷终点温度为1370℃左右;转炉终点碳的质量分数大于2.8%时能满足脱碳炉热量要求;半钢磷的质量分数平均可达到0.018%,平均脱磷率可达到79.2%。与传统单渣工艺相比,采用此工艺不仅能降低炼钢终点磷含量,也能保证脱磷的稳定性。     

四机四流高效罗可普连铸机的工艺控制

韶钢炼轧厂四机四流罗可普连铸机从意大利德兴公司引进，是目前国内较高拉速小方坯连铸机，最大拉速可达3．60m／min，平均拉速达3．3m／min。该连铸机自2000年12月投产以来，对连铸工艺不断优化，现已形成一套成熟的工艺控制，工艺故障及设备故障逐步降低，铸坯质量全面达标。     

邯钢400m2烧结机试生产及工艺参数的优化

介绍了邯钢400m^2烧结机的试生产情况及对工艺参数的测定和优化。针对燃料粒度偏细且配量大，返矿配入量波动、生石灰供应不足、烧结终点控制不当等问题，逐步采取措施进行调整，使烧结工艺参数得到优化，加 快了达产速度。     

Observed Performance of Long Steel H-Piles Jacked into Sandy Soils

Full-scale field tests were performed to study the behavior of two steel H-piles jacked into dense sandy soils. The maximum embedded length of the test piles was over 40?m and the maximum jacking force used was in excess of 7,000?kN. The test piles were heavily instrumented with strain gauges along their shafts to measure the load transfer mechanisms during jacking and the subsequent period of static load tests. Piezometers were installed in the vicinity of the piles to monitor the pore pressure responses at different depths. The time effect and the effect of installation of adjacent piles were also investigated in this study. The test results indicated that, although both piles were founded on stiff sandy strata, most of the pile capacity was carried by shaft resistance rather than base resistance. This observation implies that the design concept that piles in dense sandy soils have very large base capacity and small shaft resistance is likely to be inappropriate for jacked piles. It was also found that the variation in pore pressures induced by pile jacking was closely associated with the progress of pile penetration; the pore pressure measured by each piezometer reached a maximum when the pile tip arrived at the piezometer level. A nearby pile jacking was able to produce large tensile stresses dominating in the major portion of an installed pile; both the magnitude and distribution of the induced stresses were related to the penetration depth of the installing pile.