Earth pressure balance (EPB) tunnelling machines are commonly used for the construction of tunnels in soft soils. These machines use the excavated soil in a pressurised head chamber to apply a support pressure to the tunnel face during excavation. How well an unstable face is supported in an EPB machine depends on effectively transferring a constant pressure from the support medium to the surface of the face. If the support pressure is not constant, but instead changes, the varying pressure inevitably leads to collapse of the face or heave on the surface ground. A machine may be designed to work in “Ideal ground” conditions. However, natural soils rarely have these properties, and conditioning of the soil is usually necessary to change its properties to suit the machine. Effective soil conditioning significantly improves the machine performance and control of the soil flow through the screw conveyor. However, for soil conditioning as commonly used in practice, the effects of different conditioning treatments on soil properties and the machine performance are not clearly understood, and problems with EPB machine operations related to the soil properties are often encountered. This thesis presents experimental investigations of direct shear box tests on conditioned sands, compressibility tests on conditioned sands and a model EPB screw conveyor operating with sandy soils. Index tests were performed to investigate effects of foam and polymer conditioning treatments on the plastic fluidity of different Leighton Buzzard (L.B.) sands and Thanet sand. The index tests allowed assessment of conditioning treatments for sandy soils, and optimum ranges of treatments for Leighton Buzzard sand and Thanet sand are suggested. In the series of shear box tests, performed on conditioned Thanet sand and conditioned L.B. sands, one of the most important findings was that the pore water pressure controls the strength of the sand foam mixtures. An increase in foam injection ratio (FIR) might produce an increase of pore water pressure and a decrease of shear stress. In the series of compressibility tests, performed on conditioned Thanet sand and conditioned L.B. fine sand, one of the most important findings was that increasing FIR does not increase maximum gas expelled. The FIR and the initial relative density of the specimen have to be related to the capability of the specimen to retain the gas and establish a coexistence between grains of soil, water and gas bubbles. Finally, from the series of model (1:10 scale), screw conveyor tests, performed on conditioned Thanet sand, conditioned L.B. fine sand and conditioned Garside sand, it can be concluded that the Oxford screw conveyor model can be used as a trial machine to study the effects of different operating conditions on conditioned sand specimens similar to those used on site. This can allow choice of conditioning methods to improve the performance of an EPB machine at a given site.

Three-dimensional scour propagation along offshore pipelines is a major reason to pipeline failures in an offshore environment. Although the research on scour in both numerical and experimental aspect has been extensive over the last three decades, the focus of the investigation has been limited to the two-dimensional aspect. The knowledge on three-dimensional scour is still limited. This dissertation presents the results of an experimental investigation on threedimensional scour along offshore pipelines in (1) steady currents (2) waves only and (3) combined waves and current. The major emphasis of the investigation is to investigate the propagation of the scour hole along the pipeline after the initiation of scour. Physical experiments conducted were used to quantify the effects of various parameters on scour propagation velocities along the pipeline. The problem of monitoring real time scour below a pipeline was solved by using specifically developed conductivity scour probes. Effects of various parameters such as pipeline embedment depth, incoming flow Shields parameter, Keuglegan- Carpenter (KC) number and flow incident angle to the pipeline on scour propagation velocities along the pipeline were investigated. The investigations clearly reveal that scour propagation velocities generally increase with the increase of flow but decrease with the increase of the pipeline embedment depth. A general predictive formula for scour propagation velocities is proposed and validated against the experimental results. There are still some common issues related to pipeline scour that is lacking in the literature to date. One of these issues is the effects of Reynolds number on two-dimensional scour beneath pipelines. A numerical approach was adopted to investigate the Reynolds-number dependence of two-dimensional scour beneath offshore pipelines in steady currents. A novel wall function is proposed in calculating the suspended sediment transport rate in the model. The effects of Reynolds number were investigated by simulating the same undisturbed Shields parameters in both model and prototype but with different values of Reynolds number in two separate calculations. The results revealed that scour depths for prototype pipelines are about 10~15% smaller than those for model pipelines. The normalized time scales was found to be approximately the same, and the simulated scour profiles for the model pipelines agree well with the experimental results from an independent study. The backfilling of pipeline trenches is also an important issue to the design and management of offshore pipelines. A numerical model is developed to simulate the self-burial of a pipeline trench. Morphological evolutions of a pipeline trench under steady-current or oscillatory-flow conditions are simulated with/without a pipeline inside the trench. The two-dimensional Reynolds-averaged continuity and Navier-Stokes equations with the standard k-e turbulence closure, as well as the sediment transport equations, are solved using finite difference method in a curvilinear coordinate system. Different time-marching schemes are employed for the morphological computation under unidirectional and oscillatory conditions. It is found that vortex motions within the trench play an important role in the trench development.

Infiltration facilities are source control mechanisms that are implemented in urban developments with reduced natural permeable surfaces. Despite the development of design criteria for infiltration facilities, these systems continue to fail due to headloss development, overflow, or chemical breakthrough. The limited research on the long-term performance of these systems has emphasized the role of physical filtration mechanisms within porous media filters to address concerns surrounding system failure, namely filter clogging. A continuous macroscopic depth filtration model was developed to investigate the clogging potential of the underlying sand filter. This continuous model furthers the understanding of temporal and spatial changes in system performance for the development of more appropriate design criteria and more suitable maintenance regimes. The characterization of long-term system performance by defining three different failure modes and a probabilistic approach comprises a comprehensive methodology by considering several performance criteria rather than assuming that one criterion dictates the overall system performance.

Sewer trenches usually contain material with a higher hydraulic conductivity then the adjacent soil. Thus they can serve as paths of preferential flow in a polluted area. Wastewater from factories can also leak from wastewater pipes and pollute the soil in the sewer trenches. The purpose of this project was to investigate pollutions in sewer trenches and in sewer pipes in the industrial area of Köpmanholmen, 20 km south of Örnsköldsvik in the north of Sweden. To make an estimation concerning the potential of transport of pollutions in sewer trenches, hydrological calculations were performed. Leakage to any greater extent did not seem to be a problem in the area. This is the case both for the concrete and the wooden pipes that have served as factory wastewater pipes. A large transport in the lengthwise direction of the sewer trenches was not shown to exist. Instead the greatest risk of transport from a polluted area seems to come from infiltration into wastewater pipes, where the pollutants can flow readily to the recipient or wastewater treatment plant. / Rörgravar innehåller ofta grövre material med högre hydraulisk konduktivitet än omgivande jord och kan därför tjäna som spridningsvägar från förorenade områden. Avloppsvatten från fabriksområden kan också misstänkas ge upphov till föroreningar i rörgravar via läckage från avloppsrören. Detta arbete har haft som mål att utreda föroreningssituationen i ledningsgravar och avloppsledningar på Köpmanholmens industriområde, ca 2 mil söder om Örnsköldsvik. För att bedöma ledningsgravarnas potential att sprida föroreningar har också hydrologiska beräkningar har gjorts. Läckage i någon större omfattning från avloppsledningar har inte kunnat påvisas. Detta gäller både betongledningar och den trätub som har utgjort fabriksavlopp på området. Inte heller har någon föroreningsspridning kunnat påvisas i ledningsgravarnas längdriktning. Den största risken för spridning av föroreningar verkar istället vara via infiltration till avloppsledningarna. Detta ger en snabb transport från förorenade områden till recipient eller reningsverk.

Infiltration facilities are source control mechanisms that are implemented in urban developments with reduced natural permeable surfaces. Despite the development of design criteria for infiltration facilities, these systems continue to fail due to headloss development, overflow, or chemical breakthrough. The limited research on the long-term performance of these systems has emphasized the role of physical filtration mechanisms within porous media filters to address concerns surrounding system failure, namely filter clogging. A continuous macroscopic depth filtration model was developed to investigate the clogging potential of the underlying sand filter. This continuous model furthers the understanding of temporal and spatial changes in system performance for the development of more appropriate design criteria and more suitable maintenance regimes. The characterization of long-term system performance by defining three different failure modes and a probabilistic approach comprises a comprehensive methodology by considering several performance criteria rather than assuming that one criterion dictates the overall system performance.

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Magistratūros studijų baigiamajame darbe analizuojama melioruotų žemių ir melioracijos statinių būklė. Tyrimai buvai atliekami Trakų rajone. Trakų rajono savivaldybės duomenimis 2007 m. sausio 1d., nusausintas plotas sudaro 13980,40 ha, iš jos drenažu- 9794,30 ha žemių. Pirmoji nusausinta žemės būklės inventorizacija Trakų rajono savivaldybėje buvo atliekama 1985 m. gegužės- lapkričio mėn.. Tuo metu rajone buvo nusausinta 17740 ha, iš jų drenažu 14292 ha. Inventorizacijos metu nustatyta, kad patenkinamos būklės 1265 ha, blogos būklės iš viso- 514 ha ir numatyta išbraukti iš apskaitos – 987 ha. Antroji nusausintų žemių inventorizacija 2000 m. balandžio- lapkričio mėn.. Tų metų duomenimis rajone nusausinamas plotas buvo 22250,5 ha, iš jos drenažu 17827,8 ha. 2001 m. įvykus administraciniam rajono padalijimui buvo įkurta Elektrėnų savivaldybė ir Trakų rajone liko nusausintos žemės 13830,7 ha, normalios techninės būklės- 11209,1 ha. Remiantis naujausiais 2006 metų inventorizavimo duomenimis, neveikiančio ar blogai veikiančio drenažo plotas- 687,68 ha, rekomenduojamas išbraukti iš apskaitos-287,17 ha. Šiuo metu magistralinių griovių ilgis Trakų rajone yra 487,88 km, iš kurių 403,63 km blogos būklės. Kaip ir visi melioraciniai statiniai, taip ir grioviai, nėra amžini. Nuslinkus šlaitams, nusėdus dugne nešmenims, priaugus žolių, patekus įvairiems kliuviniams, sugriuvus pralaidoms ir drenažo žiotims, grioviai praranda savo paskirtį ir patvenkia drenažo sistemas, sumažina drenažo... [toliau žr. visą tekstą] / In the article there is analyzed the condition state of drained lands and land reclamation structures in Trakai district. The area of drained lands in Trakai district by January 1st, 2007 facts covers 13980,40 ha and 9794,30 ha of the land with drainage. The first land structures in Trakai district was accomplished in May-November, 1985. at that point 17740 ha was drain and 14292 ha of the land with drainage in Trakai district. At the time of inventory satisfactory structures 1265 ha, in bad condition 514 ha and Schedule efface from the records 987 ha. The second specification of the land inventory was in April- November 2000. by that time records the area of drained lands was 22250,5 ha and 17827,8 ha of the land with drainage. In 2001 whaen accomplished administrative district partition was foundationed Elektrenai municipality and for the Trakai district leftover of drained lands 13830,7 ha with the good technical condition- 11209,1 ha. In 2006 the drained lands in bad condition was 687,68 ha and recommended efface from the records- 287,17 ha. Have no means for the proper use and maintenance of land reclamation structures arranged in their lands, therefore their technical condition is worsening repidly. Farmers, who do not want or are not able, to maintain or take care of drainage are doing much harm to neighbos‘s drained lands.

Magistrantūros studijų baigiamasis darbas 50 puslapių, 36 paveikslų, 3 lentelės, 29 literatūros šaltiniai, lietuvių kalba. Tiriamojo darbo objektas: Marijampolės r. sausinimo sistemos, melioracijos statiniai. Tiriamojo darbo tikslas: ištirti naudojamų sausinimo sistemų efektyvumą, sausinamų žemių naudojimą ir eksploatacijos priemonių efektyvumą sąlygojančius pagrindinius veiksnius Marijampolės rajone. Pagal gautus tyrimų rezultatus sudaryti rodiklių sistemą naudojimo priemonių ekonominiam efektyvumui nustatyti. Tiriamojo darbo uždaviniai: 1. Atlikti dabartinių sausinimo sistemų techninio – ekonominio efektyvumo nustatymo metodų literatūrinę analizę, parengiant rodiklių sistemą sausinimo sistemų būklei bei jų eksploatacijos efektyvumui nustatyti; 2. Atlikti sausinimo sistemų techninės būklės, sausinimo efektyvumo tyrimus, nustatant įvertinimo rodiklių reikšmes bei skaičiavimo priklausomybes; 3. Atlikti sausinamų ariamų žemių derlingumo ir jo sumažėjimo dėl neefektyvaus sausinimo tyrimus, nustatant sausinimo sistemų naudojimo priemonių ekonominio efektyvumo rodiklių reikšmes bei skaičiavimo priklausomybes. Tiriamojo darbo metodika: tyrimai buvo atlikti Marijampolės rajone. Šiems tyrimams panaudoti matematinės statistikos metodai – duomenų grupavimas, sistemingumas, tyrimo duomenų grafinės išraiškos metodai. Tiriamojo darbo rezultatai: atlikus Marijampolės rajono sausinimo sistemų remonto efektyvumo tyrimus, buvo nustatyta kaip keičiasi sausinimo sistemų remonto... [toliau žr. visą tekstą] / Master Thesis: 50 pages, 36 pictures, 3 tables, 29 references, written in Lithuanian language. Main words: constructions, drainage, drain system, trenches. The subject of the research work: drain systems of Marijampole region, melioration constructions. The aim of the study: to investigate the efectivity of draining systems, usage of drainable lands and the main factors determinating the efectivity of exploitation of drainage devices in Marijamplole region. The specific aims of this study: 1. To perform the literary analysis of determination methods of technical – economical efectivity of present draining systems; 2. To accomplish the analysis of the technical condition of draining systems and drainage efectivity by estimating the index values and mathematical subjections; 3. To establish the investigation of richness of drained arable lands and the reduction of richness due to inefective draining, by determinating the values of economical efectivity rates of exploitation of drainage devices and mathematical subjections. The methodology of the study: the analysis was carried out in Marijampole region Mathematical methods (data grouping, mathematical organization, the methods of mathematical graph expression) of statistics were used in this study. Results: Determined the efectivity of drained lands by growing different agricultural plants; The highest efectivity index was estimated by growing potatoes and wheat. Slightly lower efectivity index obtained for buckwheat and... [to full text]

Pipejacking is a tunnel construction technique which is increasing in popularity, but fundamental research is necessary to fully understand the extent of its possible uses and limitations. This dissertation reports on laboratory research into the performance of reinforced concrete pipes, assessment of pipe joints and the use of joint packing materials. The research has addressed specific problems which the tunnelling fraternity have raised. Model pipes have been constructed at scales of 1:6 and 1:10.5 using reinforced microconcrete and they have been tested in either a sand filled chamber or between supporting yokes. Current British Standard tests have been used as a control on the quality of pipe manufacture. Data have been recorded of changes in soil pressures, pipe geometry and strains induced in the pipes. The tests have investigated deformation of pipes, deflection angles between consecutive pipes, distribution of stress concentrations and the effects of the use of joint packing materials on allowable jacking loads and induced stress magnitudes in the pipes. A review of current pipejacking practice is presented and recommendations for the control and supervision of pipejacking operations are made. The conclusions include recommendations for fieldwork monitoring and implications of this stage of the research to industry. Recommendations are made for maximum installation jacking loads for any given deflection angle between pipes. The prediction of friction angles at the pipe soil interface have been assessed at different soil stress levels and new recommendations are made. The effects of cyclic loading on the pipejacking system and transfer from jacking load to ground loading once the pipes are installed are presented. The criteria used in the selection of a recommended joint packing material for use in jacking operations have been included. Failure modes of pipes are stated and recommendations are made for pipe design, installation and monitoring to predict and prevent such failures. This dissertation is the report on the first stage of an overall programme of research which is now set to progress with monitoring of pipejacking operations on several construction sites.

Pipe jacking is a trenchless construction technique for the installation of underground pipelines. Although pipe jacking is widely used, fundamental research is still needed to understand fully the factors affecting the process and to prevent unexpected failure. With the time and financial limitation, it is difficult to explore all aspects of these factors with experiments; and it is also difficult to study them by analytical methods because of the complexity of the problem. This thesis describes the use of the finite element technique to study the pipe performance under different environments and the laboratory tests of several different joint designs. The emphasis of the current research is on the performance of the concrete pipes during jacking under working conditions and to seek possible improvements in the design of pipes and pipe joints by numerical modelling. In the finite element modelling, a simplified two-dimensional model is used for a preliminary study, then the analyses are carried out with three-dimensional models A, B and C representing a complete pipe, a pipe with surrounding soil and a symmetric three-pipe system respectively. Several factors affecting the pipe performance have been examined, for example, the properties of the packing material, the stiffness of the surrounding soil, the misalignment angle at the pipe joint, and the interaction between the pipe and surrounding soil. The numerical results show that the misalignment of the pipe is the dominating factor inducing both tensile stresses and localized compressive stresses in the concrete pipe, especially with a high misalignment angle which results in separation between packing material and the pipe. The packing materials with high Poisson's ratio and high stiffness also induce higher tensile stresses in the pipe, and the influence of Poisson's ratio is significant. Under 'diagonal' loading, both the stiffness of the surrounding soil and the interaction between the pipe and the surrounding soil have a significant effect on the stresses within the concrete pipe. Under 'edge' loading, the greatest potential damage is at the pipe joint due to the tensile stresses in the hoop direction; while under 'diagonal' loading, the damage is most likely the cracking on the external surface of the pipe along a line connecting the two diagonal loaded corners. The results show that the Australian model gives somewhat good prediction about the maximum normal stress and the diametrical contact width at pipe joint. Based on the numerical results, several different joint designs for improving the pipe strength have been proposed and tested in the laboratory. Both the laboratory tests and the back analyses suggest that the local reinforcement and the local prestressed band at the pipe joint will improve the pipe strength.