软土地区含止水帷幕的板梁式双排桩支护基坑计算研究

依托广州市西湾路地块改造项目一期工程基坑支护项目,结合MIDAS-GTS对软土地区含止水帷幕的板梁式双排桩支护进行了有限元三维数值分析研究。研究表明,基坑开挖对基坑临近区域的地表水平位移有较大的影响,支护结构前、后排桩的水平位移均呈上部大、下部小的分布趋势,随着桩身深度的增加,后排桩的水平位移降幅大于前排桩。结合计算结果及第三方监测数据,该支护形式应用于软土地区可有效提高支护体系的抗侧向变形能力,提高基坑的安全性,具有广泛的应用前景。     

软土基坑中长短桩支护的数值模拟研究

放坡+等长桩+被动区加固是武汉深厚软土基坑中常采用的支护方法,然而在软土地区按等长桩进行布置会导致支护造价较高。为了降低支护造价,以实际工程为背景,探讨长短桩在基坑支护中的最优配比选型。首先采用ABAQUS有限元和天汉基坑软件对比分析等长桩桩体的受力情况,并将监测数据与软件计算结果相对比,验证有限元软件计算结果的合理性,然后以等长桩有限元模型为基础,在ABAQUS中建立长短桩支护三维模型,分析四种不同配比的长短桩在基坑支护的受力和变形,并选出最优长短桩配比支护方式。研究表明一长一短的桩型配比支护方案相比其它三个方案更可有效支护基坑,为武汉地区类似软土基坑工程支护设计提供参考。     

排桩+钢支撑支护结构位移和弯矩分析研究

以武汉阅马场首义广场隧道工程为依托,以排桩+钢支撑支护结构为主要研究目标,采用解析法和数值模拟法对该工程中的排桩+钢支撑支护结构的位移变形和弯矩进行模拟计算,并与实测位移进行比较.对比分析计算结果,研究分析了排桩+钢支撑支护结构在基坑开挖过程中桩身侧向位移和受力弯矩的分布规律及特点.     

深基坑双排桩支护数值模拟研究

利用三维有限元软件,对采用双排桩支护的某基坑工程进行了数值模拟,分析了双排桩排距的变化、桩径的变化对支护体系水平位移、弯矩等的影响,通过对不同支护条件下的双排桩支护体系的分析,得到了相应的结论,指出桩径在800 mm~1 000 mm,排距在2.4 m~3.0 m较为合适。     

深基坑排桩复合支护技术及其应用

结合中核建材总部大厦基坑的工程地质条件与基坑周边环境,提出了排桩+内支撑+悬臂桩的排桩基坑复合支护方案。使用天汉V2005.1软件对支护结构进行了验算,结果显示基坑各分段被动区最小安全系数均大于1.2,桩身承受的最大弯矩均小于桩身弯矩设计值。经基坑监测表明,采用排桩复合支护可有效控制基坑顶部水平位移、建筑物沉降、深层侧向位移、内支撑内力均在允许范围内。     

桩锚支护在深基坑工程中的应用

结合武汉世茂龙湾一期二标段深基坑工程实践,为满足基坑支护方案的安全、经济、方便施工,根据地质条件、场地环境条件对支护方案进行优化选型,采用等值梁法进行悬臂桩加锚杆的支护结构设计,计算结果表明,该支护体系可以较好保证支护结构位移在安全范围内、支护体系安全高效,对周围建筑物影响小,节省工程费用,可为软土地区类似深基坑支护体系的设计、施工提供理论依据。     

铁路深基坑支护设计及监测分析

依据工程特点和沿海软土水文地质条件,本采用钢筋混凝土灌注桩+内支撑的桩撑支护方案,有效地控制了基坑变形,确保了项目顺利实施。在基坑开挖和地下结构施工过程中,对支护结构位移、内撑轴力及周边建筑物沉降进行了监测。选择典型部位桩顶及桩体的水平位移、内支撑轴力的监测结果与设计数值进行对比分析,结果吻合较好。可为沿海软土地区的类似工程设计、施工提供借鉴。     

滨海软土区深基坑支护结构设计及变形分析

基于三门核电站一期泵房深基坑工程的成功实践,对滨海软土区的基坑工程特点、支护结构设计和变形特点进行了详细分析。本工程依据地层条件,将基坑边坡划分为完全基岩边坡,基岩埋深小、无淤泥地层的边坡,基岩埋深较大、有较厚淤泥层的边坡三种类型,并分别采用了三种支护型式:放坡、排桩+岩锚、排桩+深搅重力墙+岩锚,有效解决了滨海软土区的地下水位高,淤泥粘聚力及内摩擦角小,基坑侧壁受水平荷载大、易失稳等难题。现场监测结果表明锚索应力及基坑的水平位移和沉降均满足规范及设计要求。三门核电站泵房深基坑支护所面临的岩土工程问题对于沿海工程具有一定的普遍性,该方案的成功应用可为沿海地区类似工程的设计提供参考。     

基坑被动区加固参数对支护结构位移影响分析

为研究软土地基区域基坑被动区加固参数对支护结构位移影响,以武汉地区某典型基坑工程为背景,采用FLAC二维数值模拟的方法,建立了有限差分基坑被动区的加固模型,并将CX6现场实测值与计算值与进行对比,验证计算模型的合理性;实测桩身应力变化规律同支护体系水平位移分布规律一致,反映了实测数据的正确性;基于模型讨论了加固区域的深度、宽度、形状参数对支护结构位移的影响;并将计算值与支护结构的实测位移进行了对比分析,验证数值模拟的精确性、合理性。结合实测值和数值模拟分析的结果表明,数值模拟可以较好地分析支护体系的实际变形规律;在武汉软弱土层地区,被动区阶梯式加固相比其他加固形式有明显的优势,具有较强的适用性;被动区加固对支护结构变形的位移影响是非常显著的;加固区域各阶深度、宽度都存在一个有效域,当超出该域后,加固效果不会出现显著提升;当各阶加固宽度与深度相当时,加固效果最好。     

深基坑施工对钢板桩围堰影响的数值模拟分析

结合武汉市东湖通道工程项目,根据地勘报告地层参数及东湖通道基坑深度,利用数值模拟软件ABAQUS对钢板桩围堰内侧基坑开挖过程中的钢板桩位移、拉结钢筋的应力及基坑周围土体位移情况进行数值模拟分析,预测围堰结构内侧基坑开挖施工过程中钢板桩围堰稳定情况及基坑周边土体位移情况,以期对实际施工提供科学的指导,提高工程的安全性和可控度.     

浅析高速公路工程招投标中的最低评标价法

结合目前高速公路施工项目招投标活动的实际情况,阐述了最低评标价法的概念,归纳了其优点及存在问题,对完善最低评标价法提出几点策略,以期促进招标投标市场更加规范有序。     

Place-Making in Megaprojects in Melbourne

This article analyses state-led place-making practices in Melbourne. The two levels of government that influence planning in Melbourne make much of the city as ‘culturally vibrant’ and ‘creative’, and have incorporated creative city-inspired place-making principles into many layers of the planning system. An examination of the development of two mixed-use megaprojects in central Melbourne reveals however that ideals of culturally engaging public places, and indeed of creative landscapes for middle-class consumption, wither in the face of more basic imperatives for economic development. In these case studies the ‘creative city’, no matter how the idea is interpreted, has little traction either as a set of inclusive place-making principles or as a gentrification strategy. The article concludes that the creative city-inspired place-making objectives in the planning system at both state and local levels are ambiguous in their overall intents and completely unsupported by statutory controls. Such place-making objectives as are realised are the compromised results of the interplay of uncoordinated decisions, delivered at the pleasure of the developer.     

Pathogens in septage in Vietnam

Septage is widely acknowledged as a major source of infectious pathogens while disposal of septage, and the operation and maintenance of septic tanks, is not regulated in many developing countries. Twenty untreated septage and septage sludge samples were taken from Can Tho City, Vietnam to examine their pathogen content, and indicator micro-organisms. Escherichia coli and Enterococcus spp. were detected in all samples, regardless of sludge storage time. Phages were detected in 80% of samples. Salmonella spp. were detected in 70% of the untreated septage and 60% of septage sludge samples. Concentrations of phages and bacteria tested in septage sludge after many years of tank storage were much higher than the expected levels. Helminth ova were present in 95% of untreated septage samples with an average of 450 ova l^− 1, and were detected in all septage sludge samples with an average of 16,000 ova l^− 1. Twelve varieties of helminth ova were identified. More helminth ova varieties in higher concentrations were found in septage than those reported from stool samples. The varieties' frequency ranged from 10% to 50% and Ascaris lumbricoides predominated. Results show that pathogens and indicator micro-organisms, especially helminth ova, accumulate in sludge. Thus helminth ova should be considered when septage sludge is treated and used for agriculture. Proper health protection measures must be applied for people handling septage.     

在市场中实践在实践中学习在学习中进步--工程公司市场化进程的回顾与展望

近两年来，工程公司在提高市场竞争意识、推动市场化进程中做了大量工作，其中坚持走出去的方针是我们自我加压、推行加快市场化步伐的一个重要战略步骤。     

新时期广东城市化的新特点

新时期广东城市化出现以下特点:知识源导向、城市由单体向群体化发展、产业集群推动、政府主导自上而下的集约化发展、城镇化向城市化转变、由重“数量”发展向重“质量”发展的转变。     

新形势下高校强化基建财务管理的探讨

在市场条件下高校基建财务人员在加强日常财务管理的同时,必须树立起高度的工作责任心,抓好事前监督、事中监督、事后监督三个环节,全面理解、贯彻执行《高等学校财务制度》,管好用好各项基本建设资金,提高基建财务管理水平,更好地完成高校各项基建任务,以有限的投资,最快的建设速度,获得最大的投资效益。     

2005年北京办公物业市场七大趋势

趋势一:CBD区域写字楼集中放量从各区域规划方案上看,CBD区域多数项目在03～04年处于项目的报批手续及拆阶段,预计2005年正式推向市场,因此2005年CBD区域将成为北京市场供应集中的域,区域即将供应的项目有北京财富中心(二期)、金地国际花园、万达广场、SOHO尚都、万通中心、世纪财富中心、怡禾国际中心、光华国际等。除去未知项目,2005CBD写字楼办公面积的供应量为60万平方米左右。中关村区域经过一段时间的集中供后开始逐步放缓,2005年供应的体量相对较大的项目有中关村金融中心、新中关。金街区域可能开盘的项目只有2个:英蓝国际中…     

浅谈我国工程项目建设成本控制存在的问题

结合目前我国施工企业工程项目成本管理现状,对工程项目成本管理过程中存在的问题进行了较详细的分析,并提出了一些解决问题的办法,以做好项目成本控制工作,进而增强企业经济实力。     

Variation in property taxation in Tulsa

Conclusions It may be reasonably concluded from this study that the range of variation in these ratios of assessed to actual value are of a reasonable size for the great majority of cases. The frequency distribution of these sample ratios was not normal, however, as was assumed a process of this type would produce. On the other hand, the failure of the regression analysis to identify any significant variables which would explain these variations would tend to re-enforce the assumption that the fluctuations were indeed of a random nature.To sum it up in one paragraph, aside from a few extreme cases, the assessing process appears to give estimates which are more consistent than would be expected under the assumption that any errors would be of a random nature, but the regression analysis was unable to isolate any particular socioeconomic characteristics which would explain the variation which was present.Financial support for this research project was furnished by the University of Tulsa.