A comprehensive review of the published work is presented on field, laboratory modelling and theoretical data relating to ground movements associated with trenchiess pipelaying techniques. Due to the similarities with convergent trenchiess techniques, soft ground tunnelling work is also reviewed. The factors that influence these ground movements are isolated and the ability to investigate these considered in terms of model tests. A test facility based on a l.5m long,l.5m high and l.Om wide steel tank has been developed and this is described together with the philosophy behind its use. The development of appropriate methods of simulating both pipejacking and pipebursting trenchiess techniques using the test facility, based on the installation of a 200mm diameter semicircular steel pipe section, are described. The use of a stereo-photogrammetry technique for the ground movement data acquisition is also reported and assessed. Three programmes of model tests were conducted: open shield pipejacking, closed shield pipejacking and pipebursting. The test programmes included investigations into the effects on the soil movements of variations in cover depth, overcut ratio (pipejacking tests), bursting ratio (pipebursting tests) and the effect of using different dry sands at different densities. From the photographs obtained during the tests, the sand displacements were determined in both the longitudinal and perpendicular planes to the pipe installation. These displacements allowed contour plots to be produced for the horizontal and vertical components of these displacements. This allowed the interaction of the various areas of sand movement to be appreciated, and the extents and magnitudes to be investigated for the changes in the factors made between each test. The extension of the results to other test conditions not directly investigated and also to the limited field data available, is made by using interpolation and extrapolation of graphical plots of the test data. These graphical plots also allowed trends in the data to be highlighted. This project involved a fundamental study of ground movements. However, guidance is given on how the results obtained from the tests can be used to determine the effects on adjacent services and structures. This is presented bearing in mind that the test results were for laboratory model simulations rather than prototype operations. Two simple theoretical analyses are described, one based on the error function curve and one using a fluid flow method. The error function analysis is used to predict ground movements in the perpendicular plane to the installation, while the fluid flow analysis, with dilation and compression capabilities, is developed to enable ground movements to be predicted in both the perpendicular and longitudinal planes. The analyses were applied to the laboratory model tests and the results correlated very well. The results of the laboratory model tests and the theoretical analyses developed, considerably extend the understanding and knowledge on the ground movements associated with trenchless pipelaying techniques.

The trenchless technology known as pipe ramming for construction of culverts and buried pipes under roadways or other infrastructure has gained significant popularity due to its cost-effectiveness and ability to alleviate surface disruptions associated with open-cut trenching. Although the experience with pipe ramming is increasing, there has been remarkably little technical guidance available for engineers to appropriately specify aspects of a pipeline or culvert installation, including the planning of feasible layouts, rates of penetration, pipe diameters, and hammers. This research provides a comprehensive engineering framework for evaluation of culvert installations at the planning phase to address the gaps in knowledge associated with pipe ramming. Presently there are no existing and proven techniques for prediction of settlement, vibration, driving stresses, soil resistance to ramming, and drivability for pipe ramming installations. This study has adopted existing drivability, soil resistance, settlement, and vibration prediction models from pipe jacking, microtunneling, and pile driving models and examined their applicability in pipe ramming installations, resulting in new and technology-specific design guidance. The development of this comprehensive engineering guidance is based on engineering calculations empirically tuned using a database of actual performance measurements. Field observations of five production installations and a full-scale experiment were conducted to form the performance database employed to understand the mechanics associated with pipe ramming installations, ranging from vertical ground movements, ground vibrations, and installation performance. Settlement prediction was evaluated using the inverted normal probability distribution based models, and these methods over-estimated the observed settlements close to the center of the pipes and under-estimated settlements at radial distances away from the pipe. A pipe-ramming-specific hyperbolic model was developed for better prediction of the vertical settlement induced by pipe ramming in granular soils. Attenuation of observed pipe ramming-induced vibrations was modeled using a simple semi-empirical approach, and the calibrated model resulted in reasonable predictions of the ground vibrations for granular soils. The static soil resistance to ramming was evaluated using the traditional quasi-static pipe jacking models and the models resulted in inaccurate predictions for instrumented pipe ramming installations. Therefore pipe ramming-specific static soil resistance models were developed for both the face and casing resistance in granular soils. Principles of stress wave theory routinely applied in the drivability analyses for pile foundations were adopted for the evaluation of the dynamic response pipes during ramming. Reliable estimates of the static soil resistance and dynamic soil parameters were obtained through signal matching processes. Data-informed drivability analysis were performed to simulate the magnitude of driving stresses and develop drivability curves which relate the penetration resistance of a given pipe and hammer to the range of static soil resistances. The study culminates in the first comprehensive framework and recommendations for the installation of pipes by ramming, and should help owners, consultants, and contractors to appropriately plan pipe ramming installations. / Graduation date: 2013

abstract: Trenchless technology is a group of techniques whose utilization allows for the installation, rehabilitation, and repair of underground infrastructure with minimal excavation from the ground surface. As the built environment becomes more congested, projects are trending towards using trenchless technologies for their ability to quickly produce a quality product with minimal environmental and social costs. Pilot tube microtunneling (PTMT) is a trenchless technology where new pipelines may be installed at accurate and precise line and grade over manhole to manhole distances. The PTMT process can vary to a certain degree, but typically involves the following three phases: jacking of the pilot tube string to achieve line and grade, jacking of casing along the pilot bore and rotation of augers to excavate the borehole to a diameter slightly larger than the product pipe, and jacking of product pipe directly behind the last casing. Knowledge of the expected productivity rates and jacking forces during a PTMT installation are valuable tools that can be used for properly weighing its usefulness versus competing technologies and minimizing risks associated with PTMT. This thesis outlines the instrumentation and monitoring process used to record jacking frame hydraulic pressures from seven PTMT installations. Cyclic patterns in the data can be detected, indicating the installation of a single pipe segment, and enabling productivity rates for each PTMT phase to be determined. Furthermore, specific operations within a cycle, such as pushing a pipe or retracting the machine, can be observed, allowing for identification of the critical tasks associated with each phase. By identifying the critical tasks and developing more efficient means for their completion, PTMT productivity can be increased and costs can be reduced. Additionally, variations in depth of cover, drive length, pipe diameter, and localized ground conditions allowed for trends in jacking forces to be identified. To date, jacking force predictive models for PTMT are non-existent. Thus, jacking force data was compared to existing predictive models developed for the closely related pipe jacking and microtunneling methodologies, and the applicability of their adoption for PTMT jacking force prediction was explored. / Dissertation/Thesis / M.S. Civil Engineering 2013

No description available.

Water distribution system pipes span thousands of miles and form a significant part of the total infrastructure of the country. Rehabilitation of this underground infrastructure is one of the biggest challenges currently facing the water industry. Water main deterioration is twofold: the main itself loses strength over time and breaks; also, there is degradation of water quality and hydraulic capacity due to build of material within a main. The increasing repair and damage costs and degrading services demand that a deteriorating water main be replaced at an optimal time instead of continuing to repair it. In addition, expanding business districts, indirect costs, and interruptions including protected areas, waterways and roadways require examination of trenchless technologies for pipe installation. In this thesis a new threshold break rate criterion for the optimal replacement of pipes is provided. As opposed to the traditional present worth cost (PWC) criterion, the derived method uses the equivalent uniform annualized cost (EUAC). It is shown the EUAC based threshold break rate subsumes the PWC based threshold break rate. In addition, practicing engineers need a user-friendly decision support system to aid in the optimal pipeline replacement process. They also need a task-by-task cost evaluation in a project. As a part of this thesis a comprehensive decision support system that includes both technology selection knowledge base and cost evaluation spreadsheet program within a graphical user interface framework is developed. Numerical examples illustrating the theoretical derivations are also included. / Master of Science

Submitted in fulfillment of the requirements of the Degree of Magister Technologiae: Civil Engineering, Durban University of Technology, 2013. / The urgent need to rehabilitate or replace ageing deteriorated buried potable water pipeline networks is one of the many critical service utility provision challenges faced within the municipalities in South Africa. The majority of these unreliable deteriorated pipeline networks consist of un-dipped (not coated with bitumen) AC piping which have long passed their planned economic and technical lifespan. Traditionally, the open trenching method has been utilised for the replacement of aged and deteriorated piping. However, this traditional open trenching method has shown to be expensive and difficult to implement, particularly in congested high traffic use urban areas. The need to rehabilitate or replace the ageing deteriorated buried potable water pipelines in South Africa, taking into account the above mentioned expensive factors has a solution. This solution is termed ‘trenchless technology’ and sometimes also termed ‘no dig’. Recent advancements in trenchless technologies now include innovative methods such as pipe bursting, close-fit lining and sliplining. Close-fit compact pipe manufactured by Wavin Overseas B.V. was newly introduced in South Africa in 2010 for the rehabilitation of deteriorated pipelines. These trenchless methods require further research into their technical application merits, drawbacks and costs in relation to the traditional open trenching method in order to determine which method is more expensive and also least suitable. Traditionally, the ‘total cost’ associated with pipe rehabilitation or replacement projects consisted only of the direct costs. The indirect and socio-economic inconvenience costs were often ignored and resulted in costly expenses to the municipalities. However, this research will show that these indirect and socio-economic inconvenience costs must form part of the total cost of a project as it assists with the successful completion of the project without expensive unforeseen costs to the municipalities. In addition, this research will provide insight as to which indirect and socio-economic inconveniences are dominantly experienced by the public. To achieve this, a quantitative socio-economic survey questionnaire was developed. This questionnaire was aimed at residents and business owners who were affected during a project of this nature. This research study will serve as a support tool to municipalities of South Africa when selecting a pipe rehabilitation or replacement method. This support tool will provide key technical merits and drawbacks of the traditional open trenching method, pipe bursting method, close-fit compact pipe method and sliplining method. In addition, this research study will compare the ‘total cost’ of the traditional open trenching method against the trenchless pipe bursting method. The decision making process lies in the hands of the municipal technical managers. Therefore, their knowledge and experience of up to date information on trenchless methods (as well as the traditional open trenching method) is vitally important. This research provides insight as to the knowledge and experience of technical municipal staff on trenchless methods, its application and use in South Africa. A quantitative survey questionnaire was developed by the researcher. This questionnaire was aimed at technical staff in the water departments of district and local municipalities of South Africa. The results of the above questionnaire surveys formed part of the eThekwini Water and Sanitation (EWS) Feasibility study funded by the Dutch Government. When comparing the costs of the trenchless pipe bursting method against the traditional open trenching method, the results revealed that trenchless methods are undoubtedly cheaper and far less disruptive to the public. The results of the socio-economic survey revealed that trenchless methods were preferred by the public since it was less disturbing and the hindrances experienced were also far less than the traditional open trenching method. The results of the technical municipal survey questionnaire revealed that at least 50% of municipal technical staff of South Africa are not adequately informed about trenchless methods, its application and technical merits and drawbacks respectively. This survey questionnaire revealed that South Africa may be advancing over the years on the use of trenchless methods, however, more educating in the form of training, seminars and other methods of marketing must be undertaken starting at a municipal level.

Comparativamente à abertura de valas, os métodos não-destrutivos de instalação, manutenção e substituição de infra-estruturas urbanas subterrâneas apresentam menor duração, necessitam de mínima ou nenhuma escavação na superfície e causam mínima interferência no tráfego, no comércio e em outras atividades locais. Avalia-se, neste trabalho, o potencial dos métodos não-destrutivos para reduzir, significativamente, os custos sociais e, conseqüentemente, o custo total pago pela sociedade, associado, por exemplo, à deterioração precoce dos pavimentos e a problemas ambientais. Os custos sociais, na maioria das vezes, são negligenciados ou até mesmo ignorados, sendo a escolha do método construtivo baseada apenas nos custos diretos. São fatores que contribuem para esse cenário a inexistência de um protocolo padrão para classificar e quantificar tais custos e o desconhecimento das tecnologias não-destrutivas por parte de engenheiros e profissionais responsáveis. Este trabalho apresenta, inicialmente, uma síntese dos principais componentes dos custos sociais e um breve resumo dos métodos não-destrutivos mais utilizados. Com um simulador de tráfego computacional foi realizada análise comparativa entre os métodos construtivos convencional (abertura de valas) e alternativo (não-destrutivo), quanto aos custos sociais referentes à interrupção do tráfego veicular e impactos ambientais. Os resultados mostraram que os custos sociais são consideravelmente menores com o emprego de métodos não-destrutivos, particularmente quanto aos custos com combustível e atrasos decorrente da interrupção ao tráfego veicular. / Compare to trench opening, the trenchless methods for installation, maintenance and substitution of buried urban infrastructure expend less time, need minimum or no excavation and cause minimum disruption of and interference to traffic, business and other local activities. In this work it is evaluated its potential to significantly reduce the social costs and consequently the total cost paid by the society, i.e., early pavement deterioration and environmental problems. The social costs, most of the time, are neglected or even ignored, being the selection of the construction method based on just on direct costs. This scenario is also due to the inexistence of a protocol to classify and quantify those costs and to the unknowing of trenchless technologies by engineers and other responsible professionals. This work presents, initially, a synthesis of the main components of social costs and a brief summary of the most used trenchless methods. With a computer traffic simulator it was performed a comparative analysis of conventional (trench opening) and alternative (trenchless) construction methods in terms of social costs associated to traffic disruption and environmental impacts. The results showed that social costs are much smaller when trenchless technologies are used, mainly due to the reduction of fuel costs and traffic delays.

Horizontal Directional Drilling (HDD) is used around the world when traditional open cut methods are not practical or impossible for installing pipelines. Maxi-sized drill rigs are the largest and most powerful directional drills and are more common in the field than ever before with over 5,000 rigs in operation world wide. The complexity of installations and the design associated with them continues to increase. This research has two main objectives. 1. Develop a real time data acquisition system for monitoring pullback forces on the product pipe; and, 2. Compare data gathered using maxi-sized drill rigs with current modelling methods using BoreAid. The first portion of the research, as listed above, required attaching multiple pressure transducers to the drilling display panel in an American Auger DD-1100 drill rig and recording, in real time, the carriage, rotation, and mud pressure as seen by the operator. This research also describes the various challenges and issues associated with developing real time in-the-bore data acquisition processes. Finally, future recommendations for further development of the in-the-bore data acquisition are discussed. The second portion of this research describes how the gathered data was processed into a workable data set. The field data was then compared to theoretical models by using the drill assistant tool BoreAid. The results of this comparison show that these models are appropriate for all size drill rigs, although some limitations are present.

Baigiamajame darbe pateikiama Jurbarko miesto, Vydūno gatvės vandentiekio ir nuotekų surinkimo tinklų vamzdynų būklės analizė. Tyrimų pradžioje vandentiekio ketinių vamzdžių linija (160 m ilgio) buvo diagnozuota televizinės įrangos GULLYVER pagalba. Nustatyta, kad vamzdyje yra išilginis trūkimas. Ištyrus esamas aplinkybes, priimtas sprendimas renovuoti vamzdyną betranšėjiniu būdu priverstinio įtraukimo metodu. Pasirinktas įrenginys Grundotrack „Mini – Gigant“. Nustatyta, kad norint atstatyti nusidėvėjusį vandentiekio vamzdyną, būtina įtraukti naują PE slėginį vandentiekio vamzdį 200 mm skersmens. Grundotrack „Mini – Gigant“ įrenginiu sulaužius senus ketinius vamzdžius, PE vamzdžiai įtraukti be kliūčių. Suskaičiavus darbų sąmatas nustatyta, kad naujo vamzdžio įtraukimas priverstiniu būdu, naudojant betranšėjas technologijas, kainavo 89168 Lt. Tokio pat vamzdžio paklojimas atviru būdu (iškasant tranšėjas) būtų kainavę 108008 Lt. Nuotakyno sistema (380 m ilgio) iš keramikinių 300 mm skersmens vamzdžių pirmiausia buvo diagnozuojama telekamera TELEMEC 100. Nustatyta, kad vamzdynas labai blogos būklės (išilginiai, skersiniai trūkimai, vamzdžio sandurų prasikeitimai ir trūkimai) ir reikalinga skubi vamzdyno renovacija. Ištyrus esamas aplinkybes, priimtas sprendimas renovuoti vamzdyną betranšėjiniu būdu, taikant rankovės metodą. / The final paper analyses the condition of the water supply and sewerage collection network pipelines of Vydūno street, Jurbarkas. First of all, the line of the cast iron pipes (160 meter long) of the water supply system were diagnosed by the use of the television equipment GULLYVER. Longitudinal split in the pipe was discovered. Upon examination of the existing circumstances, the decision was made to renovate the pipeline by trenchless mode, by applying forced pulling method. The device Grundotrack Muni – Gigant was selected for completion of this task. It was established that in order to restore the worn water supply pipeline, a new PE pressure water supply pipe of 200 mm diameter needs to be installed. After the old cast iron pipes were broken by the device Grundotrack Mini - Gigant, the PE pipes were installed without any problems. Having calculated the work estimates, it was established that installation of the new pipe by forced method, through application of trenchless technologies, cost LTL 89168. Open laying (by excavating trenches) of the same pipe would have cost LTL 108008. The sewerage system (380 meter long) consisting of 300 mm diameter ceramic pipes was initially diagnosed by camera TELEMEC 100. Very poor condition of the pipeline was determined (longitudinal, cross fractures, changes and fractures of the pipe joints) and need for urgent renovation of the pipeline was established. Upon examination of the existing circumstances, the decision was made to... [to full text]

Horizontal Directional Drilling (HDD) is used around the world when traditional open cut methods are not practical or impossible for installing pipelines. Maxi-sized drill rigs are the largest and most powerful directional drills and are more common in the field than ever before with over 5,000 rigs in operation world wide. The complexity of installations and the design associated with them continues to increase. This research has two main objectives. 1. Develop a real time data acquisition system for monitoring pullback forces on the product pipe; and, 2. Compare data gathered using maxi-sized drill rigs with current modelling methods using BoreAid. The first portion of the research, as listed above, required attaching multiple pressure transducers to the drilling display panel in an American Auger DD-1100 drill rig and recording, in real time, the carriage, rotation, and mud pressure as seen by the operator. This research also describes the various challenges and issues associated with developing real time in-the-bore data acquisition processes. Finally, future recommendations for further development of the in-the-bore data acquisition are discussed. The second portion of this research describes how the gathered data was processed into a workable data set. The field data was then compared to theoretical models by using the drill assistant tool BoreAid. The results of this comparison show that these models are appropriate for all size drill rigs, although some limitations are present.