Trenchless Technology Methods Research Articles

Comparison of Factors Affecting the Acceptance of the Trenchless Technology and Open-Trench Method Using ANP and AHP: Case Study in Iran

Comparison of Factors Affecting the Acceptance of the Trenchless Technology and Open-Trench Method Using ANP and AHP: Case Study in Iran

Environmental Impacts of Conventional Open-Cut Pipeline Installation and Trenchless Technology Methods: State-of-the-Art Review

With growing concerns about global warming and greenhouse gases (GHG), there is an urgent need to quantify and reduce the environmental impact (EI) of pipeline installation (PI). The most common and popular criterion used to describe sustainability efforts from the environmental perspective is the concept of carbon footprint (CF). A CF is the total set of GHG emissions caused by an organization, event, or product. It is expressed in terms of the amount of carbon dioxide (CO2), or its equivalent of other emitted GHGs. The open-cut pipeline installation (OCPI) method involves digging a trench along the length of the proposed pipeline, placing the pipe in the trench on suitable bedding materials and then embedding and backfilling. The trenchless method (TM) involves methods, materials, and equipment capable of the installation of new, replacing old, or renewing existing pipelines with minimal disruption to surface traffic, business, and subsurface. Choosing an appropriate low-carbon emission method to install or renew pipelines is an important task and may consider environmental concerns due to several energy-consuming activities, including material manufacturing, transportation, and installation. Because essentially, every PI and renewal project impacts the environment, it is of utmost importance for the pipeline project owner and the design engineer to evaluate this impact and take necessary actions to minimize any negative consequence. The objective of this paper is to present a literature review on progress acquired over the years in understanding GHG emissions from OCPI and TMs and to discuss a framework for CF estimation. Published papers were identified that reported GHG emissions and CF of the open-cut (OC) method and TM over a period from 1989 through 2019. This literature review suggests that for most of these PI and renewal projects, the material production phase consumes a large amount of energy and is a major contributor of GHG emissions. Higher GHG emissions in the OCPI method is a result of longer project durations and more equipment requirements compared with TMs where a smaller footprint or excavation area is used. Early phases of project planning should include appropriate ecological decisions consistent with the life cycle cost (LCC) and CF considerations. Pipe material and outside diameter should be considered during the installation phase by OC and TM to allow a detailed evaluation and comparison of their sustainability impacts. Incorporation of additional factors, such as cost and duration of the project, into the environmental analysis is recommended for the development of a comprehensive decision-making model to select the most environment-friendly PI method.

Investigating the use of no-dig technologies for underground utilities in developing countries

Major cities in most of the developing countries are becoming increasingly crowded. Conventional open-trench methods are expensive and lead to traffic disruption. The domestic government is looking at alternative approaches to install and rehabilitate aging underground utilities. The purpose of this study is to investigate the level of awareness and utilization of no-dig (i.e., trenchless technology) methods, the potential of their future growth, and their impact on social costs in a developing country. A survey was first conducted to investigate the use of trenchless technology methods in new construction and rehabilitation of infrastructure projects. The pertaining impact on social costs was then examined. Survey data were analyzed, and the potential of future growth of using trenchless technology methods was investigated. It has been found that “horizontal directional drilling” is the prevalent trenchless method used, while “robotic spot repair” is the least utilized one among all the methods used for new construction or rehabilitation of underground utilities. The results also revealed that using trenchless construction has a maximum impact on the “travel/traffic delay” type of social costs. The “horizontal directional drilling” method has the highest potential of future growth in new construction, while the “lining of pipe” was ranked first among rehabilitation methods. The data analysis results have also revealed that a critical social implication of using trenchless construction methods is their limited disruptions to the society when installing or rehabilitating underground utilities. Such social disruptions include road closures, traffic delays, and detours resulting in noise and loss of access to homes/businesses.

Multi-segment trenchless technology method selection algorithm for buried pipelines

There are many tools, models, and algorithms to aid in the selection of appropriate trenchless methods for pipeline installation or rehabilitation. However, one key concern is which method or technique provides optimum solution to the rehabilitation of multiple pipe segments rather than just a single pipe segment. Therefore, the searching criterion for an optimum decision support system is divided into two parts. First, the selection of the optimum method capable of solving the problem properly. Second, a simultaneous analysis of other parameters such as cost, time, and quality to improve the overall benefits of the project. It is observed that most of the real-world cases involves multiple segments in a single project. Therefore, an optimization of the solution must be made for those multiple pipe segments. Although use of different methods for each segment is a preferable solution, it may not be feasible in a wider consideration of project cost, quality, and time. Hence, one way to determine the optimal solution for multiple line segments is to minimize the number of methods and their anticipated total costs which include direct costs and social costs. This paper presents a mathematical approach to expedite the optimum solution by evaluating all of the trenchless technology methods capable of installing, replacing, or rehabilitating each pipe segment (a solution set) and minimizing the number of methods and their total costs.

Microtunneling decision support system (MDS) using Neural-Autoregressive Hidden Markov Model

Microtunneling is a trenchless technology method used for installing new pipelines. The inherent advantages of this method over open-cut trenching have led to its increasing use. This paper presents a general model for microtunneling decision support system (MDS) that can be used as a basis for developing more effective microtunneling design and construction. The model objectives are to: (1) develop a description of local geology that reflects the uncertainty of the information on which it is based and (2) provide the input data necessary for other decision support systems. MDS is composed of two main modules: (1) geology prediction model (GPM) module which is based on Neural-Autoregressive Hidden Markov Model and (2) excavation method selection module to select appropriate excavation method based on GPM result. In order to validate the proposed model, a microtunneling project: Zhong-he drainage water tunnel in Taiwan, was used as a case study. The result shows that the MDS model achieves these objectives to a satisfactory degrese.

Decision Support System for Microtunneling Applications

Microtunneling is a trenchless technology method used for installing new pipelines. The inherent advantages of this method over open-cut trenching have led to its increasing use since its first introduction into North America in the early 1980s. With this technology, surface disruption can be minimized, especially in urban areas, and high accuracy of installation (usually less than 2cm over 100m) can be achieved in both line and grade. But microtunneling machines are very expensive and few contractors have extensive experience with this technology. Microtunneling can also be risky when unexpected obstacles or soil changes occur. Careful constructability analysis is needed, and an appropriate microtunneling method should be selected in order to achieve successful completion of microtunneling projects. A computerized decision support system (DSS) for microtunneling was developed to support decision making for contractors who want to bid on microtunneling projects. This paper discusses the decision-making pr...

Pipe jacking a sewer under Athens

A deep level sewer installation, employing a trenchless technology method required as a result of excavations for a new freeway in Athens, is described. For the first time, pipes had to be jacked to drive sections over 200 m in length under the city. In addition to its technical merits, the method provided advantages in terms of social and environmental issues. Very little traffic disturbance was caused, together with no disruption of other services or creation of dust pollution during construction. It also did not damage the pavements of the city. This contrasts to the scars left on the roads, due to trenching. Pipe jacking, however, needs the construction of shafts along the alignment, arranged at distances determined by the cost effectiveness of the system to jack the pipes. It was decided to monitor the jacking force requirements as the pipes advanced. This response during driving was then analyzed and compared to the predictions presented by other researchers. Such measurements and analyses may allow for the formation of a database to permit the right choice of an appropriate excavation unit and the successful planning of any future similar projects.