水泥土搅拌桩复合地基静载试验检测法的安全度分析

在检测水泥土搅拌桩复合地基的承载力能否达到设计要求时 ,最常用的方法是单桩静载试验法和复合地基静载试验法。工程实践中发现 ,采用这两种静载试验方法得到的检测结果存在较大差异。笔者根据水泥土搅拌桩的基本特性 ,结合工程实例 ,对这两种静载试验检测结果存在的差异及其安全度进行比较分析 ,得出单桩静载试验法结果的安全度高于复合地基试验法结果的结论 ,因此 ,提出了一些合理化建议     

水泥土深层搅拌桩在某工程中的设计与应用

结合实际工程介绍了水泥土深层搅拌桩在复杂软弱场地中的设计及应用。     

喷粉桩施工工艺及其应用范围

喷粉桩是一种深层搅拌桩,系采用喷粉桩基成孔。运用粉体喷射搅拌法(喷粉法)原理。用压缩空气将粉体(水泥或石灰粉)输送到钻头。并以雾状喷射到加固地基的土层中。借钻头的叶片旋转加以搅拌。使其充分混合。形成水泥(或石灰)土桩体。与原地基构成复合地基。达到加固软弱地基础的目的。目前。这种桩基已广泛地应用于工业与民用建筑软土地基、公路、铁路路基的处理。以及进行坡加固和地下工程支护、防渗墙等工程上。     

水电地勘企业安全生产工作几点探讨

地勘工作是水电工程设计工作的基础性工作,它的情况直接影响到设计工作质量和水电工程建设,有必要对地勘队伍的安全生产管理工作进行分析研究,以适应水电工程建设和发展的需要. 1 安全生产现状及存在问题 (1)企业改制,专业扩展.随着电力体制改革的不断深入,主辅分离辅业改制,水电勘测设计企业的地勘单位除积极配合水电工程设计,认真搞好地勘工作外,还要拓宽业务范围,从事基础工程勘察、钻孔灌注桩、人工挖孔桩、深层搅拌桩、振冲桩、铁路隧道施工、路桥基础、高边坡治理等.     

利用承台与桩基协同工作和土的抗力作用处理桩基事故

湖南省某企业职工住宅楼成孔灌注桩基础 ,部分桩单桩承载力经静载试验后不能达到设计要求 ,必须进行处理。本文通过对事故原因分析 ,处理方案的确定 ,结构和构造措施的采用等方面 ,分析与处理了这个工程事故 ,并在技术经济效果方面进行了对比。     

水泥土深层搅拌桩在某工程中的设计与应用

结合实际工程介绍了水泥土深层搅拌在复杂软弱场地中的设计及应用。     

某污水处理厂深层搅拌水泥桩的施工监理

通过某工程实例,说明对于深层搅拌水泥桩,只有加强施工全过程的施工监理,控制好关键工序,才能保证工程质量.     

复合基坑工程中组合围护施工技术的应用与控制

主要介绍上海徐家汇路618号地块复合基坑工程的特殊部位9根据具体工况采取的地下连续墙、水泥土搅拌桩、钻孔灌注桩、高压旋喷桩等组合围护施工技术应用及控制措施,简单阐述了组合围护施工中特殊情况的处理措施,剖析了该裙房基坑充分利用桩的空间组合效应,合理组合围护的结构形式,实现了安全、可靠等预期目标.     

软土地铁隧道盾构工法端头井加固稳定性分析

以上海地铁10号线盾构隧道的进出口端头井加固为例,说明软土地区盾构端头井基坑的加固方法,重点说明高压旋喷桩和三轴搅拌桩联合加固在软土地区的应用和用FLAC软件对加固后土体进行稳定性分析。表明此种方法在软土盾构端头井加固的设计和施工的实用性,为以后同类工程的设计和施工起到一定的借鉴作用。     

北京地铁义和庄站基坑支护结构及变形监测

结合北京地铁义和庄站深基坑支护变形监测方案,并通过大量实测数据对基坑的水平变形、钢支撑和锚索拉力变化规律进行了研究;并比较排桩、内支撑与排桩、锚索两种支护形式的变形差异.监测结果表明:围护结构的变形增量主要发生在基坑深层土体开挖及支撑结构架设前后阶段,在开挖至坑底后变形趋于稳定;支撑内力增加影响因素较多,包括地面堆载及温度影响;围护结构变形与支撑轴力变化具有显著的关联性;桩撑与桩锚支护结构的变形具有一定的差异性.     

推动安全生产社会化的思考

研究了在新的形势下聚合各方资源,推动安全生产社会化的关键问题。重点分析了安全生产社会化的内涵,初步提出了推动安全生产社会化的整体设计,从组织、政策、约束三个维度研究了社会化组织体系建设,并为社会化工作的具体落实提出了安全培训、安全知识传播、安全文化、企业专项服务、政府执法支撑、事故信息共享、公众监督等七个重点工作方向,为创新开展安全生产社会化工作提供有益借鉴。     

热蠕变性对除尘滤袋PTFE缝线强力的影响

缝线是影响除尘滤袋寿命及可靠性的重要因素之一,缝线在长期热烟气作用下失效的案例愈来愈引起业界的关注。通过热态拉伸试验研究了热蠕变性对袋式除尘器滤袋用PTFE缝线强力的影响。在持续高温下对PTFE缝线进行拉伸试验,结果表明:PTFE缝线的拉伸断裂强力随温度升高而大幅下降,试验温度在250℃以上时,其拉伸最大载荷仅1~3 N(线密度1 200~1 250 den);PTFE缝线的拉伸断裂伸长率随温度升高呈现先上升后下降的趋势,在120℃左右达到最大值;高温环境对PTFE缝线的使用寿命有较大影响,缝线能在软化后受到外力作用而断裂失效,在实际工业生产中应给予关注。     

Perceptions of alcohol-impaired driving and the blood alcohol concentration standard in the United States

IntroductionAlthough the number of alcohol-impaired driving (AID) fatalities has declined over the past several years, AID continues to be a serious public health problem. The purpose of this effort was to gain a better understanding of the U.S. driving population's perceptions and thoughts about the impacts of lowering the blood alcohol concentration (BAC) driving standard below.08% on AID, health, and other outcomes.MethodsA questionnaire was administered to a nationally representative sample of licensed drivers in the U.S. (n = 1011) who were of age 21 or older on driving habits, alcohol consumption habits, drinking and driving habits, attitudes about drinking and driving, experiences with and opinions of drinking and driving laws, opinions about strategies to reduce drinking and driving, general concerns about traffic safety issues, and demographics.ResultsOne-third of participants supported lowering the legal BAC standard, and participants rated a BAC standard of .05% to be moderately acceptable on average. 63.9% indicated that lowering 30 the BAC to .05% would have no effect on their decisions to drink and drive. Nearly 60% of respondents lacked accurate knowledge of their state's BAC standard.ConclusionsPublic support for lowering the BAC standard was moderate and was partially tied to beliefs about the impacts of a change in the BAC standard. The results suggest that an opportunity for better educating the driving population about existing AID policy and the implications for lowering the BAC level on traffic injury prevention.Practical applicationsThe study results are useful for state traffic safety professionals and policy makers to have a better understanding of the public's perceptions of and thoughts about BAC standards. There is a clear need for more research into the effects of lowering the BAC standard on crashes, arrests, AID behavior, and alcohol-related behaviors.     

胶带运输机设备安全诊断的研究

根据胶带运输机实际应用情况 ,提出胶带运输机常见故障诊断及安全评估模型     

氨制冷系统压力管道安装及实验的要点

近年来,液氨管道事故的不断发生,引起了人们对氨制冷管道系统工程的高度重视.首先介绍了氨的性质,然后介绍了氨制冷管道安装及实验应该注意的一些要点,希望能对氨制冷工程的管道安装质量起到一些作用.     

Ignitability characteristics of aluminium and magnesium dusts that are generated during the shredding of post-consumer wastes

The authors investigated the ignitability of aluminium and magnesium dusts that are generated during the shredding of post-consumer waste. The relations between particle size and the minimum explosive concentration, the minimum ignition energy, the ignition temperature of the dust clouds, etc. the relation between of oxygen concentration and dust explosion, the effect of inert substances on dust explosion, etc. were studied experimentally.

The minimum explosive concentration increased exponentially with particle size. The minimum explosive concentrations of the sample dusts were about 170 g/m³ (aluminium: 0–8 μm) and 90 g/m³ (magnesium: 0–20 μm). The minimum ignition energy tended to increase with particle size. It was about 6 mJ for the aluminium samples and 4 mJ for the magnesium samples. The ignition temperature of dust clouds was about 750 °C for aluminium and about 520 °C for magnesium. The lowest concentrations of oxygen to produce a dust explosion were about 10% for aluminium and about 8% for magnesium. A large mixing ratio (more than about 50%) of calcium oxide or calcium carbonate was necessary to decrease the explosibility of magnesium dust. The experimental data obtained in the present investigation will be useful for evaluating the explosibility of aluminium and magnesium dusts generated in metal recycling operations and thus for enhancing the safety of recycling plants.     

稳定土技术在土路扬尘治理中的应用及展望

综合分析了稳定土技术用于土路扬尘污染治理的各种方法 ,在此基础上对该课题的研究及其发展提出了有关看法和建议。     

城市立交桥交通噪声变化规律与影响的研究

针对目前我国城市立交桥交通噪声影响的状况,环评预测结果偏差过大的问题,应用大量的环保验收实测数据,对城市立交桥交通噪声的变化规律与影响进行了分析研究.城市立交桥的交通噪声昼间变化幅度小于夜间变化幅度,一定时期的昼间噪声等效声级Ld与夜间噪声等效声级Ln的变化幅度不大于1.0dB(A),昼间噪声等效声级Ld高于夜间噪声等效声级Ln,其差值(Ld-Ln)多在2.5dB(A)之内.立交桥交通噪声主要是由大型车辆行驶噪声贡献的,车辆的行驶噪声夜间普遍高于昼间,对周围敏感点影响的噪声一楼最低,在桥路面以上六层楼的噪声最高,比桥面平层楼房平均高2.4～3.0dB(A),桥面下的楼房的噪声低于桥面平层楼噪声2～3dB(A).其结果对于城市立交桥交通噪声的管理与治理提供相应的参考.     

On the importance of knowing the affective meaning of job demands

Theorizing about the effects of job demands on mental health, job satisfaction and performance can be enhanced by allowing for a more complicated view of job demands. This paper describes an empirical attempt aimed at investigating facets of job demands. It hypothesizes that (1) many individuals will agree that job demands of certain kinds and strengths, will be associated with either satisfaction, or dissatisfaction, (2) that there will be no general agreement for some types of demands. Correlational analysis was performed on two independent sets of data to test the hypotheses, which were both supported. These results raised questions about the status of the concept of demands itself and a recommendation is made that it be replaced by the more neutral term ‘job demands milieu’ which can be applied to other aspects of the job environment such as task-based milieu, role-based milieu, or physical environmental milieu.     

Perceptions of the Importance and Control of Professional Problems in the Clinical Setting

The objective of this study was to identify the relative importance of culturally relevant professional problems and the degree of control over them, as perceived by dentists and dental students in Mexico City, Mexico. The dentists and students ranked 13 problems according to importance and then according to the perceived degree of control over each one. Novice clinicians were less secure about their ability to cope with the legal, financial, and clinical performance problems, whereas experienced clinicians were more concerned about occupational hazards and the dental market and culture. Both reported similar perceptions of their control of the problems. This preliminary information should support introducing into dental schools relevant practice-management courses, targeting continuing education efforts, and instituting professional counseling measures to meet the challenges posed by these problems.