浅淡沉管夯扩灌注桩的施工

1.工程实例 滁州某开发小区1幢6层商住楼,原基础设计为沉管灌注桩(377),且为摩擦端承桩,桩长为17m,钢筋笼全长配置,桩身混凝土为C25,以第④层砾石层作为桩端持力层,单桩承载力设计值R=579kN.但在试桩静载试验后,提出的单桩容许承载力为430kN.后经多方分析论证,原沉管灌注桩变更为锤击沉管夯扩灌注桩(二次夯扩),两次夯扩灌注混凝土高度H分别为3.5m和2.5m.再次静载试验报告中,单桩承载力容许值为630kN,满足设计要求.下面就以该工程为实例,简要介绍一下沉管夯扩灌注桩的施工.     

浅谈沉管夯扩灌注桩的施工

１．工程实例滁州某开发小区１幢６层商住楼，原基础设计为沉管灌注桩（３７７），且为摩擦端承桩，桩长为１７m，钢筋笼全长配置，桩身混凝土为C２５，以第④层砾石层作为桩端持力层，单桩承载力设计值R＝５７９kN。但在试桩静载试验后，提出的单桩容许承载力为４３０kN。后经多方分析论证，原沉管灌注桩变更为锤击沉管夯扩灌注桩（二次夯扩），两次夯扩灌注混凝土高度H分别为３．５m和２．５m。再次静载试验报告中，单桩承载力容许值为６３０kN，满足设计要求。下面就以该工程为实例，简要介绍一下沉管夯扩灌注桩的施工。２．施工原…     

A simple derivative spectrophotometric method for simultaneously detecting nitrate and nitrite in plasma treated water

A spectrophotometric technique is developed to simultaneously quantify nitrate and nitrite in plasma treated water. The measurement is based on examining the inflection points (wavelengths) in the derivative absorbance of the nitrate or nitrite solution. At the inflection points of the pure nitrate solution, the derivative absorbance is zero and independent of the nitrate's concentration, and thus the nitrite's concentration in a mixed nitrate and nitrite solution can be obtained by using the Beer's law at these points. The nitrate's concentration can also be achieved from the inflection points of nitrite in the same manner. The relation between the tested substance's (nitrate or nitrite) concentration and the second- or the third-order absorbances is obtained at these inflection points. Test measurements for mixed aqueous solutions of nitrate and nitrite with or without hydrogen peroxide confirm the reliability of this technique. We applied this technique to quantify the nitrate and nitrite generated in air plasma treated aqueous solutions. The results indicate that both nitrate and nitrite concentrations increase with the plasma treatment time, and the nitrite species is found to be generated prior to the nitrate species in the air plasma treated aqueous solution. Moreover, the production rate of total nitrogen species is independent of the solutions' pH value. These results are relevant to diverse applications of plasma activated solutions in materials processing, biotechnology, medicine and other fields.     

斜井双钩串车提升井口车场在煤矿的应用

详细介绍了煤矿主斜井双钩串车二次变坡高低道四股道自溜滚动运输自动摘钩排绳井口车场的设计过程。系统地介绍了主斜井双钩串车提升井口车场各技术参数的合理选取和确定,并利用AutoCAD绘图的方法进行设计。设计过程简单、直观,设计结果严谨、精准。设计的车场结构克服了传统的井口车场设计存在的问题,极大地提高了车场操作的安全性、可靠性。设计的车场自动化水平较高,最大限度地缩短了摘挂钩作业时间,充分发挥了提升系统的提升能力。