Topology optimisation techniques help designers to nd the best layout of structural members. When followed by shape and sizing optimisation, these techniques result in far greater savings than shape and sizing optimisation alone. During the last three decades extensive research has been carried out in the topology optimisation area. Consequently topology optimisation techniques have been considerably improved and successfully applied to a range of physical problems. These techniques are now regarded as invaluable tools in mechanical, aerostructural and structural design. In spite of great potential in geomechanical problems, however, the application of topology optimisation techniques in this eld has not been studied thoroughly. This thesis explores the state-of-the-art topology and shape optimisation methods in excavation design. The main problems of concern in this thesis are to nd the optimum shape of an underground opening and to optimise the reinforcement distribution around it. To tackle these problems, new formulations for some topology optimisation techniques are proposed in this thesis to match the requirements in excavation problems. Although linear elastic material models have limited applications in excavation design, these models are used in the rst part of this thesis to introduce the proposed optimisation technique and to verify it. Simultaneous shape and reinforcement optimisation is considered as well. Using the proposed optimisation techniques, it is shown that the computational effort needed for this mixed optimisation problem is almost the same as the effort required to solve each of shape or reinforcement optimisation problems alone. In the next part of this thesis, reinforcement optimisation of tunnels in massive rocks is addressed where the behaviour of the rock mass is in uenced by few major discontinuities. Although discontinuities exist in the majority of rock masses, due to its complexities, optimising the excavations in these types of rocks has not been considered by any other researcher before. A method for reinforcement optimisation of tunnels in such rock masses is proposed in this thesis and its capability is demonstrated by means of numerical examples. Lastly, shape optimisation of excavations in elasto-plastic soil is addressed. In this problem the excavation sequence is also taken into account. A stressbased parameter is dened to evaluate the efficiency of the soil elements assuming Mohr-Coulomb material model. Some examples are solved to illustrate and verify the application of the proposed technique. Being one of the rst theses on the topic, this work concentrates on the theoretical background and the possibility of applying topology optimisation techniques in excavation designs. It has been demonstrated that a properly tailored topology optimisation technique can be applied to nd both the optimum shape and the optimum reinforcement design of openings. Optimising the excavations in various types of grounds including elastic homogeneous rock masses, massive rocks, and elasto-plastic soil and rock media have been considered. Different objective functions, namely, mean compliance, oor heave, and tunnel convergence have been selected and successfully minimised using the proposed techniques. The results obtained in this thesis illustrate that the proposed topology optimisation techniques are very useful for improving excavation designs.

Thesis (M.A. Sc.)--University of Toronto, 2006. / Source: Masters Abstracts International, Volume: 44-06, page: 2869. Includes bibliographical references.

Thesis (M. Sc.)--University of Hong Kong, 2004. / Also available in print.

Thesis (M. Sc.)--University of Hong Kong, 2004.

Thesis (M. Sc.)--University of Hong Kong, 2006.

The creation of the University of Chicago archaeological field schools in 1934 at the Kincaid site in southern Illinois resulted in the dissemination of a standard excavation method, often referred to as the "Chicago Method", across the United States, primarily in the East. Before the field schools, there was no standard practice for excavating Eastern archaeological sites and little was written about the excavation methods that were used. During and after the field schools, archaeologists began to use similar excavation methods and also began to keep better records of their fieldwork. This thesis determines exactly what the "Chicago Method" of excavation was and how it changed over the years of the field schools between 1934 and 1941. This thesis also examines the history and theoretical background of archaeology prior to the formation of the Chicago field schools, the creation and history of the Chicago field schools, the relationship between the field methods and the anthropological goals of the Chicago archaeologists, and the influence of the field schools on archaeologists throughout the eastern United States because of the subsequent spread of methodology by the Chicago field school alumni.

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Student Number : 0400188H - MSc(Eng) Dissertation - School of Mining - Faculty of Engineering and the Built Environment / The occurrence of fracturing due to high stress levels is a major factor with regard to hangingwall stability in deep level gold mine stopes. However, rock falls cannot be the result of these fractures alone. Blocks in the hangingwall strata must be defined by a combination of the stress induced fractures and naturally occurring geological planes of weakness. These planes include bedding planes and joint planes. The importance of the natural joints and bedding planes in defining the instability has not been given the attention that it deserves, to the extent that there are apparently no documented, published data available on joint set characteristics. This is perhaps an indication that such data do not exist on the mines. To remedy this situation, detailed scan-line joint mapping exercises have been carried out in several geological environments in two gold mines. The joint data collected on joint geometry included orientation, spacing and length. The results presented in this dissertation are believed to be the first such data available on jointing in gold mines. The main conclusions from the interpretation of these data are that there are two dominant joint sets in stope hangingwalls and at least one of these sets is shallow dipping. In development tunnels there is one predominant set of shallow dipping bedding planes. Both in stope hangingwalls and in development tunnels, steeply dipping random joints constitute half of the mapped joints. The statistical joint data obtained was used to investigate and analyse the potential for rock falls in stopes. This involved the prediction of characteristic block parameters such as expected block sizes and rock fall thicknesses. These predictions show good agreement with measurements made of actual rockfalls (generic results). Most unstable blocks in stope hangingwalls are less than a cubic meter in size. These blocks are more likely to fall between support elements than fail the supports, whilst failure of the fewer large blocks (20%) usually involves failure of support elements. It is concluded that failure probabilities are largely related to joint geometry. Common failure modes for small blocks are single plane sliding and ‘dropping out’ whilst larger blocks usually fail by rotation. The study increases understanding of rock fall mechanisms and the support-block interaction. The results of the analyses of block stability that have been reported in this dissertation show disturbingly high probabilities of failure in the stope face area (or working area), particularly for blocks that are smaller than about 1.5 cubic metres in size. The study has demonstrated the important influence that natural joints have on hangingwall block stability, and the importance of joint mapping to produce statistical joint data that can be used in the assessment of stability against rock falls. Although joint mapping may be a tedious exercise in mines, it has been shown to give similar results regarding heights of rock falls to that interpreted from collection of empirical incident and accident record data over a ten-year period. It is considered that this could provide good input data for the design of stope support.