预应力锚杆复合土钉墙支护技术在宣钢深基坑中的应用

介绍了对施工场地狭窄、周围紧邻已有建筑物的深基坑,采用预应力锚杆复合土钉墙支护技术进行施工的情况。通过基坑支护设计、方案比较及理论验算,并在施工环节采取一些有效措施,克服了施工的难点,使预应力锚杆复合土钉墙这一支护技术在深基坑工程中得以较好应用。该施工技术缩短了工期,节约了大量资金,成功地解决了基坑边坡的强度及稳定性问题,保证了安全施工。     

兰州地区土钉墙支护受力研究

虽然兰州地区在基坑开挖时多采用土钉墙支护,但由于地层的复杂性,使得土钉墙的受力变形分析变得较为复杂,尤其是土钉墙在开挖期间土压力及土钉的受力分析,在理论与实践应用中还存在一定差距。以兰州城市规划展览馆基坑工程为例,结合理正深基坑支护结构设计软件FSPW-7.0,分析基坑在开挖时土压力及土钉拉应力的变形规律,并与现场实际监测数据进行对比分析。研究表明:采用软件FSPW-7.0计算分析时,所得的计算结果与现场实测的土钉最大拉应力及土压力吻合度较高,其计算结果可作为设计土钉墙参数选取的依据,并用以施工指导。     

北京地区基坑土钉墙设计及建议

基于北京某地铁车站基坑工程设计,对基坑土钉墙作用机理、设计方法及两者之间存在的问题进行了论述,并针对出现的问题提出了见解和建议.其对类似工程的管理、设计及施工有一定的参考意义.     

钉式锚杆锚固机理及其在红透山矿的应用

本文提出了一种新型钉式双锚头压环锚杆,同时介绍了此种锚杆的技术参数,作用机理,现场试验以及工程应用情况。同水泥砂浆锚杆与管缝锚杆相比,钉式双锚头压环锚杆锚固力大,后期锚固可靠,锚杆受力后移出量小能有效地粘结加固围岩阻滞变形,且安装打设迅速,并可立即承载,锚杆各部位结构设计合理功能齐全,适应性强。     

土钉支护设计与施工

在城市地区进行深基坑开挖支护是土木工程中最为复杂的技术领域之一,它不仅要保证基坑施工过程中的土体稳定,而且要严格限制周边的地层位移以确保环境安全.土钉墙支护是近年发展起来用于土体开挖和边坡稳定的一种新的挡土技术,由于土钉支护具有施工速度快、用料省、造价低的优点,故其已在深基坑支护中得到了广泛的应用.以下以兰州石油化工公司3#公寓楼工程为例讲这种支护模式的设计和施工情况.     

深基坑土钉支护数值模拟

基于FLAC3D的基本原理及其求解过程，对深基坑工程土钉墙支护做了数值模拟，对不同土钉长度、倾角的4种支护方案进行了对比选择。对所选支护方案的计算结果进行分析，得出一些有用的结论，对深基坑土钉墙支护设计及合理施工有一定的指导意义。     

基于基坑护坡桩+土钉墙支护措施研究分析

随着我国经济发展水平的不断提高,人们的生活水平也有了很大的改善,促使建筑行业也取得了长足的发展,在经济建设中扮演着越来越重要的角色。近年来,建筑工业的施工技术和质量要求越来越严格,本文主要探讨基坑护坡桩+土钉墙复合支护结构这一技术,从一些工程实例入手,分析其发展现状、特点及前景,对相关工程有一定的参考意义。     

矿山岩土工程深基坑施工技术研究

矿山岩土工程深基坑施工技术在地下工程中发挥着关键作用,主要包括保证地下工程的安全性、提高地下工程的稳定性、增强地下工程的耐久性和提高地下工程的可维护性。施工过程包括施工准备、土方开挖、基坑支护和地下水处理等步骤。具体应用包括土钉墙支护技术、地下连续墙施工、桩锚支护技术和逆作法施工。这些技术和方法在处理复杂地质条件下的深基坑工程中发挥了关键作用,提高了工程的安全性和效率,保障了工程的顺利进行。     

拉森钢板桩在南昌高富水砂砾层基坑工程设计中的应用

近些年来,随着南昌城市建设的快速发展,其深大基坑工程越来越多[1],据不完全统计从2012年至2016年间南昌市共审查深基坑项目317个,支护形式从最初的土钉墙、拉森钢板桩、悬臂桩,发展到双排桩、地连墙、型钢水泥土墙(SMW、TRD、CSM等工法)技术,支护形式越来越多、越来越灵活,在满足安全的前提下,节能、环保、经济的支护方案被广泛采用。本文以南昌某主市场冷冻机房基坑支护为例,介绍了外拉锚式拉森钢板桩计算、施工难易程度及止水效果分析,为后续类似基坑工程施工设计提供经验。     

土钉墙深基坑支护设计与施工

主要介绍了广州某钢铁厂加热炉工程深基坑开挖所采用的土钉墙方案的设计情况。     

Massing and Enclosure Design with SEED-Config

SEED-Config supports, in three dimensions, the schematic design of building forms and technical systems. It provides a uniform interface and computational mechanism in which to implement a variety of form making and technological design capabilities. In operation, it assists a designer in discovering potentially applicable design operations, the alternative designs that can be generated by applying operations and the previously created designs that might apply to the current design problem. Like the rest of SEED, SEED-Config represents designs as functional units that are realized or allocated by design units. A design problem is represented as a design that has unallocated functional units. SEED-Config acts through the application of technologies to allocate functional units and to further develop the functional units of the current design problem. In the most general terms, a technology is a collection of computational mechanisms to create and instantiate design and functional units satisfying the requirements of a class of functional units in a design context, based on specific construction technology or form generation principles. Using SEED-Config, we are developing technologies that create: (1) Three-dimensional building massings from schematic layouts; (2) enclosure systems around building massings; and (3) structural systems within a building massing. We discuss the first two technologies here. Technologies for building massing address architectural issues of visual composition and style. Technologies for building enclosures rely on established types of enclosure design. We use one such type, airtight insulated rainscreen enclosures, to demonstrate enclosure technologies.     

Time-Dependent Back Analysis of a Multianchored Pile Retaining Wall

A multianchored pile retaining wall was constructed to protect the cut made for the cut and cover section of the twin Trojane Tunnel. Deformation monitoring surveys were conducted and measurements of movements were carried out throughout the construction cycle of the wall and beyond. In order to determine design parameters for the soil strata embedded in a complex geological sequence, the soil-wall interaction was back analyzed using the finite element method. The technical note describes the process of selection of material parameters through careful assessment of the laboratory data and the results of the numerical back analyses. Once selected, the parameters were verified on the other cut and cover sections of the same tunnel and later used in routine design. Generally, a good agreement between predicted and observed behavior was achieved suggesting the adequate determination of the geotechnical model and the soil parameters.     

Simultaneous Prediction of Saturated Hydraulic Conductivity and Drainable Porosity Using the Inverse Problem Technique

The saturated hydraulic conductivity K and the effective porosity f are two important input parameters needed for lateral drain spacing design, as well as some other applications. The technical and economic justification, of most drainage projects, is mainly connected to these two parameters. The current design procedure is based upon calculation of the lateral spacing, using some average values of K and f within the drainage area. The objectives of this study were to introduce a new method for simultaneous estimation of K and f parameters using the inverse problem technique, and to evaluate five different unsteady drainage analytical models of the Boussinesq equation, suggested by different researchers for simultaneous prediction of the parameters. Consequently, five different analytical models for predicting water table profiles were solved, using the inverse problem technique. Each model was then evaluated. A physical drainage model of 2.2?m length, 0.3?m width, and 0.5?m height was established in the laboratory and carefully packed with a sandy loam soil. A perforated drainage pipe of 4.5?cm in diameter was installed at the bottom end of the model. Many piezometers were inserted in the soil for spatial and temporal water table monitoring. Different data sets from the experiments and literature were used for model calibration. The newly proposed approach that is based upon measuring water table profiles, at different times, was then evaluated with both constant and variable f. The predicted values of the proposed approach indicated reasonable agreement with the measured data. With variable effective porosity, the method was even more accurate to predict the water table profiles. Using the inverse problem technique, all the analytical models provided good agreement with the measured data. Among these, however, the Topp and Moody model predicted more accurate results than other models.     

Undrained Bearing Capacity of Strip Footings on Slopes

The undrained bearing capacity of foundations on or near slopes is commonly calculated using empirical equations or from design charts which have been produced based on limit equilibrium or upper bound plasticity calculations. Many of the available methods do not take account of important parameters that affect the undrained bearing capacity factor, such as the distance of the footing from the slope, the slope height, or the soil properties. This paper presents finite element analyses of strip footings on or near undrained soil slopes performed in order to investigate the influence of the various parameters that affect undrained bearing capacity. The results of the analyses are compared to available methods. It is found that while some of these methods compare well with the finite element results for certain combinations of geometrical parameters and soil properties, they cannot produce sufficiently accurate results as they either do not take account of all of the affecting parameters or are generally not conservative. Based on the finite element results, design charts, equations, and a design procedure are proposed for the calculation of the undrained bearing capacity factor Nc as a function of the undrained shear strength and the bulk unit weight of the soil, the footing width, the distance of the footing from the slope, the slope angle and the slope height.     

In vivo localization of diglycylcysteine-bearing synthetic peptides by nuclear imaging of oxotechnetate transchelation

The goal of this study was to propose a new approach of the upper tibia for intramedullary nailing. Since two years, the authors performed a transversal skin incision superior to the distal end of the patella. The patellar tendon is dissociated and the tibia is perforated through the anterior intercondylar area. The advantages of this approach versus classical techniques are discussed. This approach allows isolated tibial or femoral nailing but also both nailings during the same procedure.     

4孔氧枪喷头在25t转炉上的应用

分析了２５ｔ转炉使用４孔氧枪喷冰的设计参数，论证了喷冰和于生产的冶金效果和技术经济指标变化情况。     

Economic Design Optimization of Foundations

A geotechnical foundation design should address at least three basic requirements: ultimate limit state (ULS), serviceability limit state (SLS), and economics. Most conventional design approaches focus on ULS and/or SLS optimization, with economics being evaluated afterwards. As an alternative, this paper develops a design approach that explicitly considers the construction economics and results in a foundation that has the minimum construction cost. This design approach is expressed as an optimization process, in which the objective is to minimize construction cost, with the design parameters and design requirements as the optimization variables and constraints, respectively. This design approach is illustrated using a spread footing example. Because construction costs vary by locale, the economically optimized designs differ regionally. Sensitivity studies on soil properties and design requirements show that, for typical spread footing designs in cohesionless soils, Young’s modulus (E) and the effective friction angle (?′) are the key parameters. A quantitative assessment illustrates the importance of soil property variability on cost. It is also found that, for typical spread footing designs, a relatively stringent ULS requirement generally ensures fulfillment of the SLS requirement.     

以冷代热无取向电工钢应用中存在的问题

就国内电工钢以冷代热进展缓慢的原因进行了分析,主要是电机设计相关的技术数据没有进行更新,给中小电机设计制造带来困难。建议国家支持电器科学研究,修改相关技术手册,使电机设计满足使用冷轧电工钢的需要。     

回转圆筒干燥器主要技术参数的确定

结合设计实例,介绍了回转圆筒干燥器主要技术参数的确定,通过物料平衡计算和热平衡的计算,实现了工艺技术要求;设备运行良好,各项参数实测指标均达到或超过设计要求。