A risk management approach to safety assessment of trenchless technologies for culvert rehabilitation

Proper functioning of culverts is not only critical to protecting the transportation system from flooding but also critical to maintaining the expected service life of the overall transportation system. During the service life of culverts, they deteriorate due to many reasons such as corrosion caused by road salt, blockage by debris and sediment, poor construction techniques, etc. Trenchless technologies have been used by several State Departments of Transportation (DOTs) to rehabilitate deteriorated drainage structures without disrupting the traffic and within a relatively short span of time. These technologies provide many benefits in terms of cost, time, quality, and expected service life. However, the safety aspects of these techniques have not been discussed and documented in detail probably due to the complexity and the lack of safety standards and specifications directly associated with the techniques. This paper discusses the application of a risk assessment framework to assess potential safety issues of currently available trenchless technologies for culvert rehabilitation. The findings of the study will provide additional information to improve the decision making process in selecting and planning culvert rehabilitation projects.     

The optimum choice of trenchless pipe laying technologies

A mathematical model AZ-01, which enables the choice of optimum trenchless pipe laying technology for given input data, has been presented. In the framework of AZ-01 presentation, a classification of trenchless methods applied in the model has been given, together with the assumptions, limiting conditions, input and output quantities. The algorithm of the model has been also discussed.     

非开挖技术在天然气管道铺设中的应用

通过介绍顶管施工法和导向钻进法的特点、设备、施工方法,阐述了非开挖技术在天然气管道铺设中的应用,并对非开挖法施工的经济效益进行了分析,指出其具有先进性和优越性,以及良好的社会经济效益。     

非开挖技术在城市基础设施建设中的应用

对非开挖技术的应用现状进行了较为系统的阐述,分析了非开挖技术方法及其优缺点,针对非开挖技术在应用过程中存在的问题提出了进一步需解决的问题,以更好地发挥非开挖技术在现代城市基础设施建设中的作用。     

Survey questionnaire results of the current level of knowledge on trenchless technologies in China

With a growing population and densely populated urban environments, China is looking at alternative methods of underground pipeline installation and replacement of their aging infrastructure. Conventional open trench activities result in disruption to these urban centers through road closures, traffic delays, traffic detours, loss of access to homes and business, unsightliness, noise and general disruption for everyone. Trenchless technologies are a viable and sustainable solution to China’s buried infrastructure. Numerous challenges are present when promoting trenchless technologies in China including minimal local engineering knowledge, lack of trained contractors, lack of specifications, and system impact concerns raised by government owners. This paper presents the results of a survey questions obtained from a cross-section of 209 Chinese engineers from Shanghai, Beijing, Shengyang, Chongqing, and Guangzhou to gain a snapshot of the current level of knowledge on trenchless construction methods. The results reveal an understanding of trenchless technology in general; however, a lack of understanding of technologies such as lining of pipe, trenchless grouting, auger boring, and pipe bursting. Pipe jacking and horizontal directional drilling are currently by far the most recognized and understood trenchless technologies in China.     

市政污水管道工程中非开挖敷管技术的应用

介绍了市政污水管道工程中非开挖敷管技术的前期准备工作,论述了非开挖敷管技术的优缺点,并从材料选择、导向孔施工、泥浆配比、钻导向孔等方面研究了非开挖敷管技术的施工要点,以提高施工效率。     

Chemical and biological technologies for hydrogen sulfide emission control in sewer systems: a review

Biogenic corrosion of sewers represents a cost of about 10% of total sewage treatment cost in Flanders (Belgium) and is further increasing. In the past, research has resulted in a number of prevention methods, such as injection of air, oxygen, H(2)O(2), NaClO, FeCl(3) and FeSO(4). The possibility of biological oxidation of sulfide using nitrate as the electron acceptor has also been explored in sewer systems. However, all of these methods have a problem with the high cost (euro 1.9-7.2 kg(-1)S removal). In this review, new approaches for hydrogen sulfide emission control in sewer systems are discussed. The control of hydrogen sulfide emission by using a microbial fuel cell (MFC) can be cost-effective while the BOD is removed partially. The use of phages that target sulfate-reducing bacteria (SRB) can possibly inhibit sulfide formation. Novel inhibitors, such as slow release solid-phase oxygen (MgO(2)/CaO(2)) and formaldehyde, warrant further study to control hydrogen sulfide emission in sewer systems.     

非开挖定向钻技术在城市燃气建设中的应用

结合燃气管道非开挖定向钻穿越快速公路的工程实例,分析了定向钻技术决定工程成败的技术关键点,总结了穿越工程中轨迹设计、泥浆配置、管线探测、管材连接、导向钻进、扩孔护壁、回拖等方面的实践经验。     

A survey of heavy metals in municipal wastewater in combined sewer systems during wet and dry weather periods

During wet weather, combined sewer system overflows affect the quality of water in watercourses. For planning overflows, the lowest possible load of priority substances according to Directive 2008/105/EC is crucial and the knowledge of variability in concentrations of elements in the sewer system is necessary. The behaviour of heavy metals in a sewer system was observed in the course of dry weather flow (DWF) and wet weather flow (WWF). We found, from the comparison of concentration medians for the WWF and DWF that during wet weather periods, an increase in the concentrations of As, Cr, Cd, Pb, Mn and Fe occurs in the sewer system and the effect of nonpoint sources manifests itself. Zn, Cu and Ni concentrations decreased during wet weather periods, and Hg concentrations did not significantly change. During the WWF period, a considerable nonhomogeneity of the sewage system was demonstrated.     

Assessing the performance of sewer rehabilitation on the reduction of infiltration and inflow

Inflow and Infiltration (I/I) into sewer systems is generally unwanted, because, among other things, it decreases the performance of wastewater treatment plants and increases combined sewage overflows. As sewer rehabilitation to reduce I/I is very expensive, water managers not only need methods to accurately measure I/I, but also they need sound approaches to assess the actual performance of implemented rehabilitation measures. However, such performance assessment is rarely performed. On the one hand, it is challenging to adequately take into account the variability of influential factors, such as hydro-meteorological conditions. On the other hand, it is currently not clear how experimental data can indeed support robust evidence for reduced I/I. In this paper, we therefore statistically assess the performance of rehabilitation measures to reduce I/I. This is possible by using observations in a suitable reference catchment as a control group and assessing the significance of the observed effect by regression analysis, which is well established in other disciplines. We successfully demonstrate the usefulness of the approach in a case study, where rehabilitation reduced groundwater infiltration by 23.9%. A reduction of stormwater inflow of 35.7%, however, was not statistically significant. Investigations into the experimental design of monitoring campaigns confirmed that the variability of the data as well as the number of observations collected before the rehabilitation impact the detection limit of the effect. This implies that it is difficult to improve the data quality after the rehabilitation has been implemented. Therefore, future practical applications should consider a careful experimental design. Further developments could employ more sophisticated monitoring methods, such as stable environmental isotopes, to directly observe the individual infiltration components. In addition, water managers should develop strategies to effectively communicate statistically not significant I/I reduction ratios to decision makers.     

Quality assurance and quality control practices for rehabilitation of sewer and water mains

As part of the US Environmental Protection Agency (EPA)'s Aging Water Infrastructure Research Program, several areas of research are being pursued including a review of quality assurance and quality control (QA/QC) practices and acceptance testing during the installation of rehabilitation systems (USEPA 2011). The objectives of this research effort were to collect, analyze and summarize information on the installation and QA/QC practices for the trenchless rehabilitation of sewer and water transmission mains. In addition, consideration was given to practices related to water service lines, sewer service laterals, force mains, siphons, sewer manholes, pumping stations, associated wet wells and other appurtenances. This review was accomplished primarily by conducting interviews directly with rehabilitation technology vendors, design engineers and water and wastewater utilities that have a track record of using trenchless rehabilitation technologies within their network. This paper provides an overview of how QA/QC issues have been handled in North America for trenchless rehabilitation technologies.     

住宅智能化系统中的网络通讯技术分析

本文在讨论住宅智能化系统的基本功能和结构基础上 ,对当前主流的几种智能控制网络和通讯配置方案进行了评价和分析     

非开挖关键技术在穿越武汉长江砂层中的应用

针对长距离穿越松散砂层会塌孔抱钻的危险，综合应用了精确导向、合理设计钻孔轨迹、扩孔级配、补浆短接和优质泥浆的技术，使该铺管施工顺利完成，为今后同类工程施工提供了经验和指导。     

The comparative analysis of standards used in Poland for trenchless rehabilitation of sewage pipes and the problems in design of resin liners

The paper presents not only the comparative analysis of the three standards (German, Danish and American) commonly used in Poland for the design of resin liners, but also the chosen problems involved with the design. The attached examples of calculations give a chance to investigate the influence of noticed differences in basic assumptions on the final results including the minimum, acceptable wall thickness of the linings used for trenchless renovation of gravitational sewers.     

福州市老城区污水管道检测结果分析及修复技术选择探讨

采用闭路电视检测（CCTV）技术对福州市三八泵站上游片区污水管道进行监测,结果表明片区污水管道缺陷多,管道破裂,错口和沉积严重,急需进行修复和养护。简要介绍了国内外非开挖修复技术,综合分析各修复技术特点、适用条件、造价和国内使用情况,推荐福州市污水管道非开挖修复技术采用原位固化内衬法、折叠管内衬和螺旋缠绕内衬法。     

深层搅拌法在污水管软土地基中的应用

通过具体工程实例，探讨了深层搅拌法在污水管软土地基中的应用，介绍了深层搅拌法的施工工艺，提出了保证施工质量的措施，进行了复合地基静载试验及铝芯法试验，积累了深层搅拌法工程施工经验。     

复杂施工条件下非开挖拖拉管的施工

介绍了跨河拖拉管在没有入土位置角度的施工流程,重点叙述了木桩围堰、钢板桩井的施工及管道拖拉施工的几个注意点,并指出通过采用非开挖拖拉管施工技术,可以促进非开挖牵引铺管技术的良好发展。     

Development and applications of trenchless technology in China

Trenchless technology has developed for almost 10 years in China since the first symposium on trenchless technology was held in Beijing (Peking) in 1996 and the China Society for Trenchless Technology-CSTT was established in 1998. Driven by the dramatically increased demand for underground pipeline installation throughout the nation, China has made significant progress in research and development in trenchless technology in the past 10 years. For example, there are more than 200 contractors engaged in trenchless construction, using more than 2000 horizontal directional drilling machines, among which approximately 700 have been introduced in the last year, and the biggest HDD rig in the world is now in China. In addition, China has made many achievements in education, research, and new products development and has accomplished many challenging projects in terms of complexity, diameter and distance in this field. There is a huge market potential for trenchless technology in mainland China.This paper presents the latest research, education, training, marketing and technical status of trenchless technology in China, and discusses the potential market, trends and factors that will influence trenchless technology in the next decade in China.     

建筑新技术在工程中的应用

结合新技术示范工程应用实例 ,阐明了新技术优势 ,提倡广泛推广应用新技术 ,使科技成果转化为生产力 ,推动建筑新技术在工程中的发展     

混凝土施工中新技术的应用

介绍了泵送混凝土的施工工艺、注意事项及其特点 ,结合滨河小区A1号～A10号高层住宅楼混凝土工程应用实例 ,指出该技术既能保证工程质量、提高工效 ,又节约了材料 ,具有很好的推广前景。