Thesis (Ph.D.)--Curtin University of Technology. / Includes bibliographical references. Also available as an electronic version via the Internet.

Thesis (Ph.D.)--Memorial University of Newfoundland, 1999. / Bibliography: leaves 360-373.

Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 190-193).

Diss.--Philosophische Fakultät--München--Kudwig-Maximilians-Universität, 1999. / Bibliogr. p. 472-499.

Population grow in recent years requires an extension of the current pipeline sanitary system. For this purpose, granular excavation and landfill works are associated with pedestrian traffic congestion. Therefore, it is necessary to develop an innovative and sustainable alternative to reduce the problems generated during the execution of the conventional process. This research proposes the use of flowable fill due to the multiple advantages offered by this material. On the one hand, it is economical for medium to large trench fill volumes, considering savings in labor (it is done with a small number of workers), in equipment (does not require the rental or purchase of compaction equipment) and in time (the pouring is done by directly pumping the mixture, from the mixing machines to the excavation). On the other hand, being self-compacting and self-leveling decreases the width of the trenches, reducing excavation and filling volumes; which, in turn, incur money savings. Also, this material guarantees work safety, since people are not required inside the excavation and fill in poorly accessible areas without any problem. Dosages were established for ten flowable fill mixtures with cement contents of 50, 60, 70, 80 and 90 kg of cement and a range of admixture from 1.75 to 2.00%; The results indicated that decreasing the fine aggregate - coarse aggregate ratio, the compressive strength of the mixtures increases and the slumps of the mixtures decreases, and the compressive strength increases directly proportional to the cement content.

In the South African gold mining industry, mining is being conducted at depths of over 3 000 m below the surface. Severe fracturing and deformation of the rock occurs making it unlikely that stress analysis which treats the rock as a homogeneous elastic material will yield useful results about the behaviour around the excavation. The excavation, or stope, considered in this study is tabular. The stope occurs in stratified rock with bedding planes at approximately 1 m intervals. The height of the stope is about 1 m to 1.5 m and the length increases to over 100 m as mining progresses. Shear fractures initiate ahead of the advancing stope, which together with the bedding planes separate the rock into distinct blocks of relatively intact material. The stratified nature of the material in the hangingwall (or roof) of the excavation, and the lack of cohesion in the bedding planes, suggests that separation occurs along the bedding planes, with each layer supporting its own weight. The lowest of these layers is referred to as the "hangingwall beam". Stope closure occurs at a distance of around 30 to 40 m behind the stope face. This study focuses on the mechanics of the hangingwall beam with particular emphasis on the conditions for stable closure. In order to do this the stope is first analysed using a finite element model which treats the rock as a homogeneous elastic medium. By treating the hangingwall beam as a separate layer, 1 m thick, its behaviour is compared to that observed in practice. We find that the hangingwall beam does separate from the overlying rock, but that the axial stresses in the beam are tensile, thus contradicting the observed behaviour. In practice, compressive stresses exist in the hangingwall and footwall. It has been suggested that slip along the shear fractures generates the compressive stresses. In constructing a mathematical model of the hangingwall beam we consider the beam to be made up of blocks 1 m deep and 1 m long. The blocks are treated as a homogeneous elastic material. The behaviour of such a beam is different from that of a fully homogeneous beam, because of the possibility of the formation of hinges. By considering a range of simplified models of a beam composed of blocks, various questions regarding its stability can be addressed. These models consider beams of fixed span in which the weight is increased from zero to the full value. The largest unsupported halfspan which can be stably equilibrated is of the order of 31 m. The maximum stable deflection is 0. 4 m, and therefore additional support is required to allow closure to occur statically. The nature of a single supporting spring that will let down the beam in a limiting, stable manner is identified. Once closure has taken place, the hangingwall beam is stable. In order to obtain a realistic picture of the steady state configuration of the hangingwall beam, an analysis is performed which simulates the advancing stope face. The results show that the distance between the face and the point of closure is around 34 m which is in accord with the behaviour observed in practice. The results have shown that the model which treats the hangingwall as a beam composed of blocks provides useful information about the mechanics of the hangingwall.

If soil becomes so polluted that it can be assumed to pose unacceptable risks to health, theenvironment or natural resources, remedial action must be carried out. In 2006, aninventory study was compiled by the Swedish Environmental Protection Agency. The resultsshowed that more than 50% of the projects were completed via excavation of thecontaminated masses. Now 15 years later, the purpose of this report is to study remedialactions completed in Sweden over a 12-year period (2010–2021) and try to investigate howthe distribution of the methods used in practice reflects the development of knowledge onremediation. All 290 municipalities in Sweden were contacted and over 1000 reports ofremedial action were collected. Out of all 1000 reports only 114 was used due to the smallsize and short time allocated for this study. The result showed that in 113 of the 114 cases theremedial action was shown to be excavation, and, thus my conclusion is that excavation stillaccounted for the majority of remedial action methods used. It is not possible, based on theresults in this report, to determine exactly which factor or to what extent each factorcontributes to the majority of ex-situ remediation in Sweden. Probable reasons are the highcommercial availability of excavation remediation and traditions that exist in the industry,which means that it will not be possible for in-situ methods to establish themselves andbecome financially sustainable.

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A fundamental element of the observational method in geotechnical engineering practice is the utilization of a carefully laid out performance monitoring system which provides rapid insight of critical behavioral trends of the work. Especially in tunnels, this is of paramount importance when the contractual arrangements allow an adaptive tunnel support design during construction such as the NATM approach. Utilization of measurements can reveal important aspects of the ground-support interaction, warning of potential problems, and design optimization and forecasting of future behavior of the underground work. The term back-analysis involves all the necessary procedures so that a predicted simulation yields results as close as possible to the observed behavior. This research aims in a better understanding of the back-analysis methodologies by examining both simplified approaches of tunnel response prediction but also more complex numerical methods. Today a wealth of monitoring techniques is available for tunnel monitoring. Progress has also been recorded in the area of back-analysis in geotechnical engineering by various researchers. One of the most frequently encountered questions in this reverse engineering type of work is the uniqueness of the final solution. When possible errors are incorporated during data acquisition, the back analysis problem becomes formidable. Up to the present, various researchers have presented back-analysis schemes, often coupled with numerical methods such as the Finite Element Method, and in some cases the more general approach of neural networks has been applied. The present research focuses on the application of back-analysis techniques that are applicable to various conditions and are directly coupled with a widely available numerical program. Different methods are discussed and examples are given. The strength and importance of global optimization is introduced for geotechnical engineering applications along with the novel implementation of two global optimization algorithms in geotechnical parameter identification. The techniques developed are applied to the back-analysis of a modern NATM highway tunnel in China and the results are discussed. / Ph. D.

In the present research a highway twin tunnel project completed in Japan in 1998 is used as a case study to verify results of numerical analyses with measurement data. Each of the tunnels had approximately 1.1 km of length. For this project a wide geometry of approximately 18.0 m was selected by the designers to facilitate three lanes per tunnel. A sequential tunneling technique known in Japan as the "TBM pilot and enlargement method" was used along with NATM principles. The tunnel was used as a reference project, involving performance testing and extensive monitoring in order to verify and standardize support requirements for other tunnels excavated under similar geologic conditions in the Tomei II expressway. The tunnel was excavated in a region consisting mainly of soft sedimentary rocks, such as locally weathered sandstone, underlain by interbedded sandstone and mudstone. Due to observed non symmetric deformations and loads in the tunnel, the distinct element and the convergence-confinement methods were used during the numerical simulations. A parametric analysis was performed initially in a pseudo-continuum approach to study the behavior of the wide tunnel geometry under various conditions. The effects of rock mass elastic modulus, in situ Ko ratio and boundary conditions are discussed. More complex parametric studies were performed in a stochastically generated model by using joint spatial data from geotechnical investigations. The Barton-Bandis constitutive law was assumed for the behavior of the joints. The sensitivity of the ground "characteristic curves" was examined by statistical variation of the joint shear strength parameters. A final simulation using the code UDEC and the convergence-confinement method yields interesting results which are comparable to the monitored data. / Master of Science