沙坡变电站谐波分析与治理

针对沙坡变电器谐波严重超标的220kV变电站提出了谐波治理的措施,达到既能补偿无功又能滤除谐波的目的.通过计算分析,该方案能够满足无功出力的要求且具有良好的谐波效果.     

某工程中心挡墙的破坏机理及变形监测研究

由于工程地质情况不清，某工程中心挡墙曾发生过破坏，文章分析其破坏机理，并从安全的角度探讨其适宜的变形监测方法：测点及基点的布设、测点的埋设、观测方案、观测精度与测量限差。然后从实际观测结果出发，分析该工程的安全性。     

宝钢热电设备基础弯曲变形计算中产生沉降量计算值差异的原因分析

文中从群桩效应和土体受压变形的时间效应阐明了大型设备基础按弹性支点上筏板计算其沉降量和按“实体基础”计算其沉降量产生差异的原因。     

尾砂胶结充填挡墙受力分析及工程应用

胶结充填过程中挡墙的稳定性是重要的安全保障,结合工程实际,通过现场挡墙侧压力监测试验,研究充填过程中挡墙受压情况.试验结果表明,挡墙受充填料浆静水压力、动水压力和固化膨胀力的影响,在充填后期受力最大,最易发生破坏.用公式拟合部分试验数据,结果吻合得很好.通过以上研究计算得到了合理的挡墙厚度.     

冻土工程特性及变电站建构筑物防冻措施分析

通过对冻土的工程特性研究,分析了常温及低温环境下,粘性土不同含水率对应的力学参数。并针对冻土对变电站建构筑物基础的影响,提出了设置砂砾垫层、选择独立式基础或桩基础、减少基础外侧冻切力等三种具体工程措施。该成果可以为冻土地区电力工程建设提供参考。     

变电站通信网络常见故障分析及处理

介绍了变电站通信系统的基本结构及常见通信故障产生的原因,并分析了常见故障的处理方法,最后提出了防范措施。     

基于新型挡墙的吹氩中间包内流场及温度场优化

提出了一种新型多孔挡墙-气幕挡墙组合的控流方法,以某厂单流板坯中间包为对象,对比分析了使用新型挡墙装置前后中间包内流场、温度场及RTD曲线,随后对新型挡墙的参数进行优化。结果表明,新型挡墙组合气幕挡墙的中间包内钢液流场、平均停留时间、死区体积及温度分布均较优于无挡墙、仅气幕和仅新型挡墙方案;新型双挡墙的导流孔半径60 mm相较于40、50和80 mm方案,钢液平均停留时间增加2.15～28.7 s,死区体积比减少0.4%～3.1%,进出口温差降低0.1～0.3 K,低温区体积减少0.07～0.75 m³,且挡墙间包底所受冲击较小;气幕挡墙距长水口840 mm相较于1 040、1 180、1 320与1 520 mm方案,钢液温度分布和包底所受冲刷差别较小,而平均停留时间增加6.57～25.39 s,死区体积比减少0.9%～3.2%。     

转炉炉壳的变形分析及延长炉壳寿命的措施

分析了转炉炉壳变形的原因,提出了采用炉壳强化冷却的措施来控制炉壳变形,延长炉壳寿命,实现转炉炉壳的长寿化。     

金属材料热处理变形及开裂问题分析

随着社会发展速度的不断加快,各种工业建设飞速发展,金属材料的使用量越来越大,对金属材料的使用要求也越来越高,需要对金属材料进行各种处理,才能够使其满足使用要求,热处理工艺便是金属材料常见的一种处理工艺,其应用十分广泛,优势也颇多,但是其内也存在有变形和开裂问题,为了更好的提高金属材料的使用性能,文章便就此问题进行了浅要分析。     

变电站五防功能不完善分析及整改措施

电网中五防闭锁系统是保证电网、设备和人身安全的重要措施,也是防止电气误操作的一种技术手段.深入分析了变电站五防功能不完善存在的问题,并针对这些问题提出了一些整改措施.     

Database for Retaining Wall and Ground Movements due to Deep Excavations

A database of some 300 case histories of wall and ground movements due to deep excavations worldwide is presented. Although recognizing the weakness in the approach, a large database is used to examine general trends and patterns. For still soil sites, movements are generally less than those suggested in the well-known relationships proposed by Clough and his coworkers. However, for walls that retain a significant thickness of soft material but have a high factor of safety against basal heave, movements are similar to those calculated using the Clough charts. In these cases, when soft ground is actually present at dredge level, the Clough charts will underpredict movement and need to be used with care. For the above cases there is no discernible difference in the performance of propped or anchored systems but there is some evidence to suggest top-down systems perform better. In cases where there is a low factor of safety against excavation base heave, large movements can occur, but the Clough charts will give reasonable preliminary estimates of the likely movement in such cases. Cantilever walls have shown displacements that are often independent of the system stiffness. There is evidence to suggest that, in the case of cantilever walls and for all walls in stiff soils worldwide, design practice is conservative. Finally, the inclusion of a cantilever stage at the beginning of a construction sequence seems to be the main cause of unusually large movements.     

环冷机挡料墙受力分析及改造

首秦龙汇矿业有限公司球团厂自投产以来,环冷机挡料墙陆续出现了一些问题,包括耐材脱落、后侧壁板烧坏、挡料墙损坏、脱落等,严重影响了正常生产。为此,我们通过计算、分析,提出了一系列改造措施并予以实施。改造后,挡料墙使用寿命由三个月延长到至少一年半,取得了很好的效果。     

Time-Dependent Back Analysis of a Multianchored Pile Retaining Wall

A multianchored pile retaining wall was constructed to protect the cut made for the cut and cover section of the twin Trojane Tunnel. Deformation monitoring surveys were conducted and measurements of movements were carried out throughout the construction cycle of the wall and beyond. In order to determine design parameters for the soil strata embedded in a complex geological sequence, the soil-wall interaction was back analyzed using the finite element method. The technical note describes the process of selection of material parameters through careful assessment of the laboratory data and the results of the numerical back analyses. Once selected, the parameters were verified on the other cut and cover sections of the same tunnel and later used in routine design. Generally, a good agreement between predicted and observed behavior was achieved suggesting the adequate determination of the geotechnical model and the soil parameters.     

挡土墙优化设计初探

挡土墙是应用比较广泛的构筑物,它的设计要考虑使用要求、周围环境、总图条件、地基情况、抗震设防、冻土深度及墙体总高度等因素,关键因素则是墙体总高度;由于挡土墙的计算是基于几个假定理论进行的近似计算,因此,合理选用材质、造型、构造等对于实现设计方案优化显得尤为重要.较大的挡土墙工程,经优化设计后可降低工程造价且能加快施工进...     

土与复合桩支护结构变形破坏分析

对深基坑在7种不同复合桩支护结构条件下开挖分别进行了弹塑性有限元模拟,根据计算结果分析了土与复合桩支护结构在不同条件下的变形特点和破坏模式.     

基于理论与数值分析的衡重式挡墙优化设计

衡重式挡土墙价格低廉,施工工艺简单,在实际工程中应用广泛。在市政道路拓宽改建过程中,由于受到施工现场已建道路管线以及场地空间有限等因素的影响,传统的衡重式挡土墙由于自身尺寸较大,与现有管线等冲突,无法满足设计要求。通过对衡重式挡土墙截面进行优化,降低了作用在墙身的土压力,进而减小了挡墙本身的尺寸,避免了现场地下管线的改迁,取得了良好的工程效益。     

Performance of a Cantilever Retaining Wall

Earth pressure cells, tiltmeters, strain gauges, inclinometer casings, and survey reflectors were installed during construction of a reinforced concrete cantilever retaining wall. A data acquisition system with remote access monitored some 60 sensors on a continual basis. Analyses of the data indicated development of the active condition after translation of about 0.1% of the backfill height. The wall rotated into the backfill as a rigid body, but the top of the stem deflected away from the backfill, approximately equal in magnitude and opposite in direction to the displacement from rigid body rotation. Loading on the wall back-calculated from strain gauge readings was consistent with active earth pressure. The maximum lateral force, about the same as the design value, occurred during compaction of the backfill. Observations that differed from standard assumptions included the passive earth pressure in front of the shear key being less than 10% of the design value and vertical stress below the heel being greater than the toe. Compaction-induced lateral stresses on the stem were sometimes twice the vertical stress.