地下连续墙施工中若干问题的探讨

本文对地下连续墙设计过程中的钢筋网保护层、钢筋网接头、钢筋网预埋件、墙体锚固深度、槽底清孔等各个环节中影响连续墙质量的一些问题进行了探讨。     

振膜阻尼式料位器的原理及应用

本文所述的料位器是利用振动阻尼的原理研制的。其外形为圆柱形,它是由振动膜(用金属薄板制作)、驱动器(也是换能器)、电子电路等组成。其特点是:感应面(振动膜)是一个与外壳镶为一体的金属平面。安装使用时即可探入设备内部,也可与设备内壁成一平面,不受湿度、粉尘、污物的影响。经特殊加工可应用于特殊环境,检测不同物料的定点位置。通过在大连第一和第三粮库的烘干塔上使用表明,用振动阻尼的原理制作的料位器,在复杂恶劣的环境中检测粉粒物制的定点位置,性能稳定可非。是现已采用的料位器所不能比拟的。     

Test and Analysis of an Existing Tunnel Vibration Induced by Blasting Construction of Diaphragm Wall

According to the blasting construction of the diaphragm wall of Puxi approaching section of East Fuxing Road river-crossing tunnel,the monitoring project of the vibration of the existing tunnel induced by the blasting construction is put forward,which includes the sensors' location,monitor method and the vibration monitoring system.Based on the monitoring data of the explosion vibration,the vibration wave forms,velocities,acceleration responses,main frequencies and fields of measure points are analyzed under the conditions of three locations and different charge quantities.According to the safety-judging standard of explosion vibration,the conclusion that the existing tunnel is safe under the explosion vibration is then drawn.Furthermore,the spectrum characteristics of three explosion vibrations and the spectrum changing properties of explosion vibration wave transmitting in different directions are concluded,which can provide reference to similar projects.     

某大桥锚碇基础深基坑开挖模拟

用有限元方法模拟了某大桥锚碇基础深基坑开挖过程。模拟结果表明圆形地下连续墙的拱效应有效地减少了墙体的侧移；施工误差对结构受力和变形有重要影响；墙体嵌岩部分拉应力和压应力都很大。所得出的结论为此类基坑支护结构设计和施工提供了理论依据和实践参考。     

Construction of an ultra-deep diaphragm wall: a case study

This paper presents a case study on an ultra-deep diaphragm wall with a depth of 110 m constructed in Ningbo City. The in-situ application shows that using Bauer BC40 cutter machine in conjunction with cutter wheels specified for different strata would be qualified for constructing the 110 m diaphragm wall with high efficiency and precision given that the quality of slurry and poured concrete can be guaranteed. The ground settlement can be effectively controlled by using the overlapping construction method. Sliding failure as a whole characterized by pronounced lateral deformation is likely to occur in the upper muddy clay layer due to its high compressibility and sensitivity. In contrast, local collapse of trench walls tends to happen in the sandy silt strata. Furthermore, careful attention should be paid to sandy silt during the entire construction period as the vertical displacement of the sandy silt continues to develop even after concrete pouring     

歌唱中的呼吸

呼吸是歌唱的先决条件,了解呼吸的原理,学会正确运用歌唱中的呼吸,才能在教学和演唱实践中收到更好的效果。     

基于ABAQUS的贮箱金属膜片的优化设计

金属膜片是推进剂贮箱重要的组成部分,工作时,在外部气压作用下金属膜片从边缘处开始翻转,挤压推进剂将其排出,为外部装置提供驱动力。由于金属膜片翻转试验代价太高,在工程应用中不可能通过做大量实验来验证,往往依靠数值模拟的方法经验性地获得膜片翻转时的数据。因此,采用简单有效的数值计算方法可靠地模拟金属膜片的翻转过程对于推进剂贮箱的设计和应用具有重要的意义。     

提高混凝土管桩抗弯能力的理论与试验研究

先张法预应力混凝土管桩,尤其是薄壁管桩抗弯能力不足,往往由于施工过程土侧压力或位移造成管桩出现裂缝或其他工程问题。因此,提高管桩抗弯能力对避免或减少管桩工程质量事故有一定的作用。管桩是一空心细长预应力混凝土预制构件,在沉桩过程当中除受到竖向压力(或打击力)外,由于相邻桩沉桩过程土体的侧移挤压作用,使得已沉管桩还受到水平推力的作用。所以管桩可以视为一受弯或压弯构件来建立受力模型。因此,提高管桩抗弯能力也就是要提高管桩抗侧变形能力。本文通过实验和数值分析表明在预应力混凝土管桩中添加钢筋混凝土横隔,能提高管桩的抗弯和变形能力。     

景深及影响景深的因素

运用几何光这原理推导出景深的数学表达式，并讨论了影响景深的各种因素。     

声乐训练中歌唱呼吸技巧探讨

歌唱呼吸分为胸腹式呼吸法和腹式呼吸法,而腹式呼吸法是最适合歌唱的,掌握了腹式呼吸技法就能演唱出最优美的歌声。