富水砂层中钢管片冻结法更换盾尾刷技术探析

通过介绍钢管片冻结法更换盾尾刷技术在佛山地铁某盾构区间富水砂层中的应用,包括停机位置选择、补浆加固、冻结钢管片和预拆环拼装与设计、地层冻结、预拆环拆除、盾尾刷更换等一些列施工环节,来阐述钢管片冻结法更换盾尾刷技术在富水砂层等软弱地层中具有更好的安全性、经济性、高效性。相比较地面注浆加固,混凝土管片开孔冻结等传统加固措施,钢管片冻结法更换盾尾刷技术具有更好土体冻结效果,盾构周边冻结帷幕发展速度快,能够较好节省施工工期、同事减少工程预算开支和施工难度,降低在软弱地层中更换盾尾刷的风险,确保在盾尾刷更换期间的安全,值得在软弱地层中大力推广。     

复杂工程环境下富水软弱地层内盾构出洞接收关键技术分析

基于天津地铁5号线张兴庄站盾构出洞接收工程,针对下穿既有铁路和3号线地铁的复杂工程环境以及在富水软弱地层内掘进的不利地质条件,进行轨道加强、注浆、人工地层冻结、钢护筒和惰性砂浆等多项综合施工关键技术设计,详细阐述轨道加强方式、注浆参数、惰性砂浆配合比、人工冻结管布置等设计要点,针对各项关键技术提出相应的施工要求,并最终分析各项技术的施工效果。     

冻结法在富水圆砾地层联络通道施工中的应用

针对南宁地铁联络通道冻结法施工,采用Midas-GTS建立三维有限元模型对富水圆砾地层联络通道冻结法施工的安全性进行了验证,阐述了富水圆砾地层中冻结施工的关键技术,根据施工监测数据分析了冻结效果,最后总结了施工中的主要风险和应对措施。数值计算结果表明,按照设计冻结方法形成的冻结壁承载能力满足要求。冷冻机运转36d后,冻结法施工中去回路盐水温度、冻结帷幕温度和冻结帷幕厚度均达到设计要求。冻结法应用于富水圆砾地层中,主要风险在于地下水位变化和土体坍塌,应当有针对性地采取措施,保证施工顺利进行。     

软弱富水地层冻结帷幕施工技术研究

结合在淤泥质软弱富水地层中应用冷冻法进行地铁盾构区间旁通道施工情况介绍,就冻结帷幕设计,水平冻结孔施工,以及地层冻胀融沉控制等技术,进行了相关分析研究.     

地铁联络通道冻结法施工中涌水成因及防治

以某富水砂卵石地层联络通道人工冻结法施工为依托,就地层热力学参数、冻结参数和施工工艺等对冻结壁的厚度、交圈时间及平均温度等影响进行了研究,分析表明:AGF冻结效果关于热传导系数的敏感度最大,关于比热容和含水率的敏感度次之;冷冻管间距对冻结效果的影响非常显著,冻结法施工时,应加强冻结管开孔位置及倾斜度的控制;冷冻管直径变大,盐水与地层间对流系数减小,会抵消冻结管直径增大的影响;保温层设置不当以及冻结管远端定位缺陷直接影响联络通道与盾构隧道交叉区域的冻结效果,甚至出现冻结壁厚度不足和冻结壁交圈困难等问题,易导致管片开挖时涌水事故的发生。     

冻结法在广州地铁3号线施工中的应用

在富水性地基土中暗挖法施工地铁工程,采用人工冻结地层开挖及结构施工,阐述了冻结法加固地基土机理及施工工艺,通过测温和沉降监测,分析冻结法隧道施工过程中土层温度、荷载与沉降的关系。     

华东冷冻法联络通道开挖涌水情况分析与处理

处于富水砂层中的联络通道施工,选用冻结法加固土体具有冻结壁均匀性好、强度高及封水性好等优点。但在施工过程,如控制不到位,也存在冻结壁交圈效果不理想,导致开挖过程中出现涌水涌砂情况,结合该工程事故原因分析及处理情况,总结言水软土地层联络通道冷冻法施工的薄弱点。     

人工水平冻结法施工隧道冻胀与融沉效应模型试验研究

人工冻结工法作为土木工程特殊施工技术,在富含水软弱地层工程施工中有着显著的优点,但是此工法对地下管线、地面建筑物以及对冻结壁稳定性和可靠性的影响不容忽视。本文以广州地铁3号线某隧道水平冻结施工工程为原型,根据相似准则,建立集温度场、湿度场和力学场于一体的大型物理试验模型。通过模拟开挖过程,研究人工水平冻结法施工冻结壁形成规律、冻胀与融沉效应问题。模拟试验数据分析表明,水平冻结法施工可在隧道周围快速形成闭环冻结壁,有效保证一次支护前隧道围岩的稳定性;在施工中宜采用快速冻结或间歇冻结,有效控制积极冻结时间和冻结壁厚度,减少因水分迁移造成的冻胀位移量;浅埋暗挖隧道引起了明显的地表下沉位移;解冻过程中地表融沉位移较大,对环境影响较大。     

白垩系地层煤矿立井冻结壁的力学特性及温度场研究

为解决人工冻结技术在西部井筒穿越白垩系富水地层的技术难题,以甘肃新庄矿风立井冻结工程为背景,通过室内物理力学试验、现场实测及有限元数值模拟,对冻结状态下白垩系地层岩石的热物性及力学特性进行研究,探讨凿井期冻结壁的受力机制,重点分析白垩系冻结壁的冻结压力变化规律和成因,对比测温孔与冻结壁径向温度的实测与模拟结果,拟合得出冻结壁受混凝土水化热的影响范围为440~480 mm。研究结果为丰富我国岩石力学的基础理论研究起到积极作用,也可对西部冻结法凿井的优化设计和安全稳定性研究提供依据。     

富水粉砂地层杯形水平冻结法端头加固技术

苏州地铁5号线竹园路站西端头井土体加固使用人工冻结法,结合盾构进出洞施工,介绍冻结法方案设计、施工方法、施工工艺、施工关键点、冻胀融沉及控制措施等。工程实践表明,冻结法适合在地下水位高、土层强度低的地区使用,加固富水砂层效果显著、安全可靠。     

污泥制砖存在问题浅析

污泥制砖符合国家的环保政策,但在技术方面还待进一步创新和突破。为此分析了污泥制砖在技术方面、环保方面和社会大众认可方面存在问题及相应的改进措施。     

干旱区绿洲环境下的新疆小城镇建设投资

一、研究区域基本现状新疆地处欧亚大陆腹地,地貌轮廓表现为“三山夹两盆”,山地与平原的面积大致各占50%,镶嵌于戈壁沙漠的绿洲仅有7万平方公里。新疆土地面积166.49万平方公里,占全国总面积的六分之一。气候干旱,荒漠广布,是中国最大的干旱区,是亚洲干旱核心区,也是世界上著名的干旱区之一。水资源短缺,生态极度脆弱。新疆2004年底有1950万人,人均GDP已经超过了1000美元,城镇化进入了快速发展阶段,特别是小城镇的发展速度较快。但新疆特殊的干旱区绿洲环境,使得小城镇的发展存在许多问题。一是城镇规模小而散,基础设施配套差,城镇集散和…     

Levels of manganese in the urine of female farmers in non-polluted regions in Japan

Nearly 1500 urine samples were collected from female farmers in eight regions widely scattered in the islands of Japan in the winter of 1987-1988. The samples were analysed for manganese by wet ashing and flameless atomic absorption spectrophotometry under strict quality control. The values observed after adjustment for a specific gravity of 1.016 were distributed log-normally with a geometric mean of 0.65 microgram/l and a geometric standard deviation of 2.47. There was no effect of aging or any effect of smoking on the urinary manganese concentration. The inter-regional difference may be present but not yet conclusive. As no sex difference was observed in a previous study, it may be possible to deduce that the value may possibly stand for the "background" level of both men and women, either smoking or non-smoking, among the general Japanese population. The observed value is discussed in comparison with values reported in the literature.     

Typification of Fires in Buildings in Spain

Although the Dirección de General de Protección Civil (DGPC), an agency of the Spanish government, has been responsible for the collection of data and the statistical analysis of fires since 1985, it has not as yet issued any reports. It is true that a couple of studies have been made, but in neither case did they use a standardized methodology but relied simply on the heterogeneous information provided by the fire brigades which cooperated in the studies. At that time Spanish fire brigades did not have special units for professional fire investigation, nor was the information derived from standardized methodologies suited to research purposes. In addition, information was extremely scarce and basic, focussed only on the fire, the use of the building and personal data of the victims. In this context, the project for a Fire Investigation Unit in the Fire Brigade of Málaga (the sixth largest Spanish province in inhabitants) was set up. Although inspired in the methodologies used in the USA and in the UK, the aim was to create a customized methodology for the first scientific investigation of fires in Spain. Our research was conducted in 2007. Using the methodologies of the USA and the UK, our own methodological approach and the Spanish regulations, we drew up a questionnaire with 110 variables arranged into 6 modules. We studied 96 fires out of the 154 emergency fire calls received in 2007, having omitted some emergency calls for various reasons. Our results revealed that it was necessary to generalize the installation of fire extinguishers in residential buildings, to train the general public in the use of these devices, to promote the use of fire and smoke detectors in residential buildings, to encourage the inspection and control of old electric installations and to monitor the new installations, to generalize the implementation of emergency and evacuation plans and to design new systems and materials for the cabinets where hand-held extinguishers are stored.     

分光光度法测水中余氯

介绍了用双硫腙分光光度法测定水中余氯的新方法，阐述了其测定试验过程，根据试验结果显示，其结论符合国家标准，表明该方法可用于自来水等样品中余氯含量的测定，结果比较准确。     

Intersections of inequality in homeownership in Sweden

Abstract

Inequalities relating to ownership of housing have become a major issue de jour in many Western societies. This article examines how the distribution of homeownership in Sweden relates to two factors widely seen as significant to such inequalities, namely parental tenure status and place of birth. We use longitudinal registry data to examine the bearing of these two factors on individual-level tenure progression since the beginning of the 1990s for persons at different stages of their housing careers. We extend existing understandings of Swedish homeownership patterns by demonstrating that inequalities relating to place of birth and parental tenure intersect with one another in ways that substantially advantage certain subgroups while disadvantaging others, and by demonstrating that experiences of entry into homeownership have in recent years been changing in markedly different ways for these different subgroups. Overall, Swedish homeownership inequalities, far from dissipating, appear to be hardening along existing lines.     

莳花在城市绿化中的应用

目的:花化、香化、彩化已成为城市园林绿化的主要趋势,也是为满足人们对环境要求越来越高的一种心境。方法:选择采用莳花能表现出品种繁多,色彩艳丽等不同的方式,从而能在很大程度上丰富了植物造景的层次感要求。结果:能使其达到美化环境、增添节日气氛、提高绿化品质等方面有着突出的作用。结论:莳花造景对城市的美化可达到立杆见影效果,从而提高城市的形象和品位。     

日本城市浅层地下空间利用的新成就

本文结合日本川崎市站前广场和神户市哈巴兰德地区的立体化再开发，分析介绍当前日本浅层地下空间开发利用的成就和特点。     

遗传算法在边坡稳定系数计算中的应用

边坡稳定性的关键问题是确定最危险滑动面(潜在最危险滑动面)和边坡的稳定系数。国内外一般是采用先假定边坡滑移模式,然后近似确定最危险滑动面,再求近似的边坡稳定系数的方法来分析边坡的稳定性,但假设的边坡滑移模式难以反映边坡滑移的实际状态。因此本文探索利用遗传算法搜索最危险滑动面,并得到最小稳定系数及对应的最危险滑动面曲线,取得了较好的效果。     

地质情况复杂地区高速公路隧道地质预报研究

针对地质情况复杂地区垫邻高速公路设计、施工中的具体问题，从地质预报的方法、原理方面入手，对地质情况复杂地区高速公路隧道施工中的地质超前预报工作进行了深入的研究，在分析归纳的基础上，提出合适的工作方法。