世博轴及地下综合体的基坑工程设计

世博轴及地下综合体工程的基坑长约1000m,宽约100m,按基坑开挖深度不同分为三部分。地下两层区段开挖深度约12m,基坑保护等级为三级,采用重力式挡土墙或放坡结合800mm厚地下连续墙的边环板半逆作围护设计;地下浅三层区段开挖深度约为17m,基坑保护等级为三级,采用重力式挡土墙或放坡结合1000mm厚地下连续墙的边环板半逆作的围护设计;地下深三层区段开挖深度21.5m,基坑保护等级为二级,采用1000mm厚地下连续墙结合全逆作的围护设计。对各部分基坑给出了主要的监测结果。大尺度基坑的围护问题得到了安全经济的解决。     

泵站工程基坑施工

文章介绍了上海LB泵站开挖深度达14.4m基坑工程的施工技术,地下土层含厚达10余m的粉土冲填层,该基坑邻近高级住宅楼及其它地下建筑设施,基坑开挖难度很大。采用包括基坑围护方案,施工要点和施工监测等施工措施,成功地完成了该基坑的施工。     

浅谈基坑支护加固的设计与施工技术

1概述广州某工程原设计为地下二层,地上30层的双塔住宅楼,由于修改建筑使用功能,修改后的设计为地下三层,地上28层的集商业、餐饮、办公、住宅于一体的综合性大楼,总建筑面积为67051m2。2原基坑支护设计该工程原基坑开挖周长约320m,基坑底面设计标高为-8.45m～-9.15m,开挖深度为7.84m～8.75m。从安全、经济、合理、可行的角度出发,本工程基坑支护采用土钉支护,局部配合超前钢管桩、预应力锚杆的综合支护方案,并根据场地的工程地质条件和周边环境情况的不同,采用五个工况的支护段。2.1基坑北面该段基坑开挖边线紧靠公路而且地下管线较多,(长6…     

大型地下人防工程深基坑施工技术

杭州市市重点项目的地下人防工程,建筑面积约60 000 m2,基坑开挖最深为14.5 m。基坑支护采用多种支护形式相结合的设计方案,地下2层为钻孔灌注桩作支护排桩,设1道水平支撑,沿排桩外侧增设1排搅拌桩作止水帷幕。基坑内外全采用深井降水。着重讲述深井降水施工及降水的保证措施。通过精心组织施工,工程进展顺利。基坑开挖监测结果与施工过程验证了此方案是安全、经济、合理可行的。     

复杂地质条件下深基坑施工中的关键技术

上海长风地区2号(西)地块工程地下4层,基坑开挖深度超过18 m,局部挖深大于21 m,基坑土层中砂层厚,近坑底有贝壳层,周围环境特殊.介绍了钻孔灌注桩成孔、围护地墙成槽、基坑降水设置减压井、挖土等质量控制措施,通过监测信息化指导施工,保证了工程的顺利进行.     

基坑监测技术在某深基坑工程中的应用

上海某工程位于市中心,地下4层,基坑挖深19.55 m,周边三侧毗邻市政道路,地下管线密布;东侧距原多层房屋仅6 m,上海地区又属软土地区,地下水位高,基坑及周边环境安全至关重要。通过基坑监测,能够实时反映施工过程中引发的土体性状及围护体系、邻近建筑物、地下设施的变化情况,为设计及施工提供参考依据,控制基坑变形。     

软土基坑工程中环形内撑式支护结构的应用技术

高层建筑基坑一般都处于繁华市区，周围道路、地下管线复杂，环境对开挖引起的土体变形敏感，但目前的基坑设计理论尚不完善，并有一定的地区局限，因此，支护结构的合理设计及施工过程中的现场监测和信息反馈十分重要犤１犦。本文介绍瑞安市人民医院病房综合大楼基坑围护工程的设计方案与监测。１工程概况浙江省瑞安市人民医院综合病房楼建筑面积３８０００m２，采用框架－剪力墙结构，其中主楼２４层，地面高度９５m；１层地下室，局部夹层；裙楼５层，建筑面积约２００００m２。基坑工程开挖深度７．０３～７．４３m，电梯井处为１０．４…     

砂土地基超深基坑设计若干设计要点探讨及实例分析

工程位于杭州市钱江新城,基坑开挖范围内以粉砂性土为主,粉砂性土属高水位强渗透性地基。地上由299 m超高层塔楼及其裙房组成,地面以下为4层地下室。基坑开挖深度21.55 m,核心筒最大开挖深度约28.65 m。本文详细介绍基坑工程概况、设计方案、栈桥对撑一体化设计、深层地下承压水处理与现场监测等内容。此方案可供类似工程基坑围护设计参考。     

广州五山路地铁车站深基坑支护与监测分析

广州五山路地铁车站深基坑(17.7m)周边毗邻基础较差的天然地基多层民宅和交通流量较大的岳洲路,为确保基坑施工安全,采用地下连续墙加多道钢管内支撑支护方案。在施工过程中对基坑施工进行了详细监测,取得了丰富的监测数据,并依据监测进行施工调整,可供类似工程借鉴。     

地铁站工程深基坑的施工监测方法

某地铁站工程基坑开挖深度 2 3m ,采用地下连续墙加内支撑的支护方法 ,为保证基坑开挖及结构施工安全 ,采用信息法施工 ,本文介绍其监测方法、监测设施、数据处理与反馈。     

Strategies for Handpump Water Supply Programmes in Less-Developed Countries

ABSTRACT Community water supply programmes in developing countries frequently utilize wells or boreholes equipped with handpumps as the technology of choice. Whilst simple targets concerning numbers of wells to be drilled or villages to be served are often prominent, the wider objectives of such programmes are rarely expressed in quantified terms and, as a consequence, programme impact is often disappointing as well as difficult to evaluate. Because objectives are not clear, programme strategy fails to include all the issues and activities which are necessary to achieve the maximum beneficial impact on participating communities. In the paper, target objectives, checklists of programme activities, and staffing requirements are proposed. The subject of programme impact is briefly discussed, and a realistic approach to programme evaluation is outlined. The paper is intended both as an aid to project planners and as a guide to managers and evaluators of existing well-handpump programmes.     

基于现场监测的深基坑施工动态风险评估

目前常用的基坑风险评价方法主要是根据专家经验完全进行定性分析,存在很大的主观不确定性。以监测项目作为基坑风险的评价指标,并考虑监测项目之间的相对重要性关系,建立了基于现场监测的深基坑工程施工期风险评估指标体系。以监测报警值作为参考标准将监测数据量化为监测项目的安全风险概率;风险损失以监测项反映的可能风险源采用专家调查法进行估值;兼顾考虑基坑的安全风险概率和风险损失对基坑的风险度进行了分级,并根据风险度等级处理要求作出风险响应。通过工程实例对该风险评估方法进行了应用分析,表明该方法具有信息明确、动态、可靠的特点。     

内蒙古北山鹿咀子锑矿矿床成因及成矿时代

鹿咀子锑矿属热液脉状锑矿床,以辉锑矿为主要矿石矿物,赋矿围岩为石炭系红柳园组长石石英砂岩、含砾长石石英砂岩及二叠纪辉长岩。成矿物质主要来源于石炭系红柳园组中的玄武岩和安山岩。北西向断裂为成矿流体运移提供了通道,是主要的导矿构造。高角度的北东向走滑断裂切割区内北西向断裂及辉长岩体,是主要导矿及容矿构造。赋矿岩石为沿北东向断裂破碎带产出的碳酸岩化石英脉。芨芨泉辉长岩LA-ICP-MS锆石U-Pb年龄为(276. 6±1. 7) Ma,结合控矿构造特征,认为北东向断裂活动及其伴随的锑矿化时间,至少要晚于276. 6 Ma。     

国家游泳中心“水立方”结构设计优化

国家游泳中心“水立方”的墙体和屋盖结构创造性地采用了新型多面体空间刚架结构体系,该结构的弦杆选用矩形钢管、腹杆选用圆钢管,节点为焊接球节点。虽然结构的构成类似网架结构,但结构构件的受力状况完全不同于网架结构的二力杆,而表现为类似空腹网架的刚接梁。杆件内力包含弯矩、轴力、剪力、扭矩,弯曲应力大于轴向应力,所以结构的优化较为复杂。本文结合具体的结构设计,全面介绍了结构设计计算中的优化内容,包括:“强墙弱盖”优化,墙体杆件和屋盖杆件选用不同应力水平控制;截面类型优化,放弃加劲肋截面而改用紧凑型截面,充分发挥截面塑性,提高结构延性;几何构成“杂交”优化,将屋盖下弦贯通内墙,为减小屋盖与墙体交界处杆件过大的弯曲应力而附加少数腹杆,形成局部汇交力系;“铰接”优化,采用铰接计算处理策略,将少数弯曲应力较大无法满足规范要求的杆件两端处理为铰接,加强其周围相关杆件,再刚接迭代计算,较好满足承载力要求;“强节点弱杆件”优化,提高结构延     

Determination of the main hydraulic and poro-elastic properties of a limestone from Bourgogne, France

This study is a part of a large experimental program intended to characterise the effects of increasing temperature upon the hydraulic and poro-mechanical behaviour of a limestone from Anstrude, France. Methods of measurement as well as experimental devices, designed by our laboratory, are presented and commented on. Permeability values, measured on six different samples, either with gas or ethanol, clearly show that the results obtained with the two fluids are virtually identical as soon as the gas measurements are corrected for the Klinkenberg effect. As the permeability is not very sensitive to confining pressure variation, it can be assumed that the intact rock is slightly cracked. This is confirmed with microscopic observations as well as poro-elastic property measurements. Concerning the latter, various ways of obtaining their values are presented and compared. They include drained and undrained bulk modulus, Biot and Skempton coefficients and Biot modulus; the consistency between these parameters is finally highlighted and demonstrates that the classical theory of poro-elasticity hold very well for such a rock, which is almost monomineralic with quite a high porosity.     

地热水水源热泵在校园建筑的应用

探讨了校园建筑冷、热负荷的特点,介绍了适用于校园建筑供暖、供冷的冷热源。结合某工程实例,研究了以水源热泵机组作为冷热源的水源热泵系统,针对校园建筑冷、热负荷特点,修正了冷热负荷。分析了水源热泵系统的经济性、环保性及校园建筑采用水源热泵作为冷热源的优势。     

Comparative performance analysis of concentric-tube-type heat exchanger at various operating conditions with copper and aluminium tube materials

Concentric-tube-type heat exchanger is selected as a thermodynamic system for this research work. Different materials (copper and aluminium) are used for tube of heat exchanger. Entropy generation, exergy destruction, entransy and entransy-based thermal resistance are evaluated at different mass flow rates/inlet temperatures/specific heats of working fluids (hot/cold fluids). In addition, different tube materials and various outer/inner tube diameters of heat exchanger are also taken as parameters. And then combined effects of all these parameters are analysed. Finally, performance characteristic charts are generated. Analyses are done for counter flow heat exchanger as well as for parallel flow heat exchanger. Computer software is developed and all these analyses are done using prepared computer software. These evaluations are important to identify those operating conditions at which the heat exchanger’s performance is best and optimised.     

Significance of the soil in environmental quality improvement--a review

The broad outlines of plant and animal ecology are indicated and ecosystems are defined. The impact of agriculture and industry on these systems is indicated. The major forces bringing about instability of the soil are pointed out. Wind erosion, water erosion, nutrient and oxygen balances are described in principle. Intensification and specialization of agriculture are described in some detail. These intensive practices are compared to the older “normal” agriculture. Hence, the courses of the modern agricultural problems in environmental pollution and waste management are indicated. The magnitude of the pesticide problem is defined and the need for regulation is emphasized. Special consideration is given to chlorinated hydrocarbons and mercury compounds. The process of eutrophication is defined and is described as a natural process. Sources of artificial enrichment of the water are described as well as city and rural waste water.The remedial measures that need to be taken to maintain and/or improve the environment are discussed. Systems of handling animal wastes are described in some detail. Dry, slurry, and wet systems are described in regard to management. The control of excessive fertilizer nutrients, pesticides, and agricultural chemicals including heavy metals is outlined in some detail. Animal manure management as a part of the soil fertility system is described. Nitrogen and phosphorus management is discussed in some detail. Utilization of city waste water and sewage treatment plant sludges are indicated. Solid waste disposal on the land as a means of environmental improvement is considered from the point of view of disposing of raw sewage, sewage sludge, and solid wastes generally. Fruit and vegetable processing wastes can be treated by a process of overland flow in order to bring about adequate oxidation of these wastes. Wastes from packing plants for animal processing are much stronger wastes and require more complex treatment than fruit and vegetable processing wastes. Oil-spills as a pollutant on land are described in more or less quantitative terms. Remedial measures are given.     

基于SAP 2000 API功能的桁架结构优化设计

将改进的序列线性规划法和SAP 2000最新推出的API功能相结合,两者互动对桁架进行优化。其数学模型以设定截面形式的杆件的面积和桁架节点坐标为设计变量,以结构的最小重量为目标函数,以杆件的强度、刚度、稳定性、构造要求以及结构整体挠度为约束条件。优化后结构重量降低13·81%,优化效果显著。     

基于DEA 的建筑工程项目综合优化研究

质量、成本、工期是工程项目管理的三大主要控制目标。首先以工期目标为变量,分析工期-成本、工期-质量的非线性关系,分别建立成本、质量目标与工期目标之间的量化非线性关系模型,进而建立三者之间的多目标优化模型。结合工程网络计划优化技术,用关键路径法进行若干次工期压缩,得到不同工期、成本、质量水平的若干施工方案,组成待选方案集,通过数据包络分析的方法分析不同方案的投入、产出效率,进而根据效率值择优选取施工方案。并结合算例证明了该优化方法的有效性,为项目决策提供支持。