软弱围岩中连拱隧道爆破震动测试分析

结合闲林隧道爆破施工,对软弱围岩中连拱隧道爆破震动进行监测,分析了震动波在软弱围岩和支护结构中的传播及分布规律.研究表明,爆破最大振速一般出现在第一个峰值上;爆破震动对爆破面前后10 m范围内的中隔墙影响较大,随着距离的增大,震动波衰减明显;建议软弱围岩中连拱隧道开挖最大装药量控制在8 kg以内.研究结论可为类似条件下连拱隧道的爆破施工参数设计和现场监测提供借鉴与参考.     

山岭隧道爆破施工中初衬结构变形实时监控的研究

探讨了目前山岭隧道爆破施工时安全监测手段上的不足点,希望探索一条通过爆破过程中及爆破后的初衬形变的监测,实现施工中的安全监测方法.结合杭绍台高速公路台州段隧道施工,通过安装在初衬钢拱架拱腰部位的二维位移传感器,连续监测在爆破前后的钢拱架二维位移情况.及时捕捉到了爆破后的位移动态响应和滞后相应.为建立基于监测二维位移方法...     

小净距隧道群爆破动力分析

采用有限元软件ANSYS对某高速公路小净距隧道群进行爆破动力分析,得到钻爆施工过程中新建隧道爆破施工产生的地震波对既有隧道的影响程度,提出新建隧道爆破施工的控制速度参考值,并对小净距隧道群爆破施工开挖顺序进行优化。     

船体外板大拼接焊缝高效无尘喷砂除锈器

为适应船体外板大拼接焊缝大范围高效环保喷砂除锈,开发大腔室多枪旋转高效无尘喷砂器,并对其气固两相流特性进行研究.将整个喷砂过程置于一个直径100.0 m m以上的密闭腔室,采用单/双喷砂枪通过电机高速旋转喷枪对工件表面进行喷砂,并基于真空负压对反弹的磨料和冲蚀掉的铁锈、油污、粉尘等进行回收、分离和循环再利用.采用基于欧...     

Determination of t8/5 cooling times for underwater local dry welding of steel

Knowledge of thermal history is the basic condition for studying the structure - properties of welded joints. The determinant of thermal history is the thermal cycle, whose in-situ measurements are still a big challenge. Water as the welding environment complicates this issue even more. The article presents a method to determine an equation for calculating t_8/5 cooling times for underwater gas metal arc welding of unalloyed steels using the local dry cavity method. The work uses the contact method of temperature measurements with the use of thermocouples to obtain the temperature changes of the points of welded joints covered by the thermal field. On this basis, the values of the t_8/5 cooling times were determined. A regression analysis of the Response Surface Method was used to determine the equation, which resulted in a second-order model with interactions. Statistically significant factors were determined (thickness of welded elements and heat input value) and the model veracity was confirmed as the assumptions of normality and homogeneity of variance (homoscedasticity) of the residuals were met. The t_8/5 cooling time values depend on the thickness of the welded elements and heat input value in a nonlinear way. In terms of the test conditions, the cooling times ranged from 3.0 to 7.7 s. The equation allowed for the calculation of t_8/5 cooling times during underwater welding of unalloyed steels using the local dry cavity method based on the variability of the experimental conditions with satisfactory accuracy.     

激光除锈在船舶分段除锈中的应用

针对绿色造船技术发展对船舶分段清理除锈的工艺需求，研究船舶分段激光除锈技术。对不同表面状况的船舶分段试验样板开展激光除锈试验，在清洗效果、作业环境和投资运营成本等方面，与传统的喷砂除锈进行对比，分析激光除锈效果及适用性。结果表明，激光除锈技术应用于船舶分段除锈，具有能耗低、污染小、工作环境好等优点。激光除锈可为船舶分段除锈提供一种新的方法。