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.

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

Thesis (Ph.D)--Geosystems, Georgia Institute of Technology, 2010. / Committee Chair: Frost, J. David; Committee Member: Burns, Susan E.; Committee Member: Gokhale, Arun; Committee Member: Mayne, Paul W.; Committee Member: Rix, Glenn J. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Pipe jacking, has seen a rise in popularity, particularly in urban areas where infrastructure does not permit cut-and-cover methods. As pipe jacking has becomes more commonplace, engineers are pushing the limits of the technology more and more by designing longer drives in more difficult ground conditions. Lubrication is essential to reduce the frictional resistance generated at the pipe-soil interface. Even though lubrication is widely utilized, there is not a clear understanding of the conditions required to obtain the full benefit of lubrication. This dissertation focuses on bentonite slurry characteristics and interface behavior under different lubricating conditions with the goal to further the understanding of the mechanisms responsible for the large friction reductions observed in the field. An interface shear device capable of measuring interface behavior on pipe surfaces was used to perform tests under two lubricating conditions. Pipes were sheared against a mixture of sand and slurry and the effect of the slurry was quantified. In another series of tests, slurry was injected at the pipe-soil interface. An axisymmetric interface shear device was developed to further investigate the lubrication mechanism associated with injection of slurry into sand. The device was designed to inject slurry through injection ports built into a shaft displaced within a sealed sand-filled chamber. A series of tests were performed on dry sand as well as sand where water or slurry was injected during shearing. The effect of sand type and viscosity are also investigated. Findings from the experimental studies are related back to full-scale behavior with the objective of assessing the lubrication methods and their effectiveness. A rational procedure for predicting non-lubricated and lubricated jacking forces is proposed to optimize design and serve as a framework for evaluating jacking forces in the field.