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

The majority of faults display a layer of crushed wear material ("fault gouge") between the fault blocks, which influences the strength and stability of faults. This thesis describes the results of a numerical model used to investigate the process of comminution in a sheared granular material. The model, based on the Discrete Element Method, simulates a layer of 2-D circular grains subjected to normal stress and sheared at constant velocity. An existing code was modified to allow grains to break when subjected to stress conditions that generate sufficient internal tensile stresses. A suite of five numerical runs was performed using the same initial system of grains with sizes randomly chosen from a pre-defined Gaussian distribution. A range of confining pressures was explored from 4.5 MPa to 27.0 MPa (in case of quartz grains with average diameter of 1 mm). The average effective friction coefficients of the five simulations were relatively unaffected by comminution and displayed a constant value of about 0.26. The amount of breakage was directly related to both the applied confining pressure and logarithm of the displacement along the fault. The particle size distribution evolved during the runs, but it was apparently determined only by the cumulative number of grain breakage events: two runs with the same number of breakage events had identical particle size distributions, even if they deformed to different extents under different stress conditions. These results suggest that the knowledge of both the local displacement and stress state on a fault can be used to infer the local particle size distribution of the gouge.

H-removable sequences, for arbitrary H, under &Lambda^* construction are presented here. In the first part we investigate Neighborhood Distinct (ND) graphs and ask some natural questions concerning disconnected H and H complement. In the second part, we introduce property * and investigate graphs that satisfy property *. Consequently we find $H$-removable sequences for all graphs H with up to 6 vertices except for G60. G60 is the only graph with up to 6 vertices for which neither it nor its complement satisfies property *. The last part of our work focuses on good and bad copies of arbitrary graphs $H$ and how to interchange from one to the other. The number of ways to count all possible copies of H in H_{pn} ^ &Lambda^* is also presented via examples.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第17864号 / 工博第3773号 / 新制||工||1577(附属図書館) / 30684 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 後藤 仁志, 教授 戸田 圭一, 准教授 原田 英治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18934号 / 工博第3976号 / 新制||工||1613(附属図書館) / 31885 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 後藤 仁志, 教授 戸田 圭一, 准教授 原田 英治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

This study investigates the February 17th, 2006 massive rockslide that occurred in the island of Leyte, Philippines following heavy rainfall and four minor earthquakes. The rockslide is considered one of the largest and most catastrophic slides in the last few decades as it completely inundated the village of Guinsaugon, taking the lives of approximately 1,400 of the 1,800 residents of the village. The distinct element simulation of the rockslide is performed using 3DEC (Three-Dimensional Distinct Element Code) in order to investigate the underlying triggering mechanism of the slide as well as the behavior of the debris flow. The 3DEC models were established based on field observations from the U.S. Reconnaissance team and material and joint properties based on in-situ and laboratory test results. The possible triggering mechanisms considered in the distinct element analyses were the rainfall-induced hydraulic pressurization of the fault forming part of the main scarp, as well as the seismic acceleration due to the minor earthquakes that occurred the morning of the slide. The results of the analyses and simulations indicate that the rainfall-induced hydraulic pressurization of the fault was potentially the main trigger for the initiation of the slide. The minor earthquakes, which occurred before and around the time of the slide initiation, appeared to have very little effect on the triggering mechanism and the debris flow are comparable to witness accounts and field observations. The results presented in this study are expected to provide better understanding of rockslides such as the one that occurred in the Philippines on February 17, 2006. With further improvements in computational capabilities in the future, distinct element simulations can have the potential to reliably predict the initiation and behavior of slides, and help mitigate their impact. / Master of Science

<p>The equivalent continuum approach uses equivalent propertiesof rock mass as the input data for a continuum analysis. Thisis a common modeling method used in the field of rock mechanicsand hydrogeology. However, there are still unresolvedquestions; how can the equivalent properties be determined andis the equivalent continuum approach suitable for modeling thediscontinuous fractured rock mass.</p><p>The purpose of this paper is to establish a methodology todetermine the equivalent hydraulic and mechanical properties offractured rock masses by explicit representations of stochasticfracture systems, to investigate the scale-dependency of theproperties, and to investigate the conditions for theapplication of the equivalent continuum approach for thefractured rock masses. Geological data used for this study arefrom the site characterization of Sellafield, Cumbria, UK. Aprogram for the generation of stochastic Discrete FractureNetwork (DFN) is developed for the realization of fractureinformation and ten parent DFN models are constructed based onthe location, trace length, orientation and density offractures. Square models with the sizes varying from 0.25 m× 0.25 m to 10 m × 10 m are cut from the center ofthe each parent network to be used for the scale dependencyinvestigation. A series of the models in a parent network arerotated in 30 degrees interval to be used for investigation oftensor characteristic. The twodimensional distinct elementprogram, UDEC, was used to calculate the equivalentpermeability and compliance tensors based on generalizedDarcy’s law and general theory of anisotropic elasticity.Two criteria for the applicability of equivalent continuumapproach were established from the investigation: i) theexistence of properly defined REV (Representative ElementaryVolume) and ii) existence of the tensor in describing theconstitutive equation of fractured rock The equivalentcontinuum assumption cannot be accepted if any one of the abovetwo criteria is not met. Coefficient of variation and meanprediction error is suggested for the measures toquantitatively evaluate the errors involved in scale dependencyand tensor characteristic evaluation.</p><p>Equivalent permeability and mechanical properties (includingelastic modulus and Poisson’s ratios) determined onrealistic fracture network show that the presence of fracturehas a significant effect on the equivalent properties. Theresults of permeability, elastic moduli and Poisson's ratioshow that they narrow down with the increase of scale andmaintain constant range after a certain scales with someacceptable variation. Furthermore, Investigations of thepermeability tensor and compliance tensor in the rotated modelshow that their tensor characteristics are satisfied at acertain scale; this would indicate that the uses of theequivalent continuum approach is justified for the siteconsidered in this study.</p><p>The unique feature of the thesis is that it gives asystematic treatment of the homogenization and upscaling issuesfor the hydraulic and mechanical properties of fractured rockswith a unified approach. These developments established a firmfoundation for future application to large-scale performanceassessment of underground nuclear waste repository byequivalent continuum analysis.</p><p><b>Keywords :</b>Equivalent continuum approach, Equivalentproperty, Representative Elementary Volume (REV), DistinctElement Method, Discrete Fracture Network (DFN)</p>

The Distinct Element Method (DEM) and Discontinuous Deformation Analysis (DDA) are the two most commonly used discrete element methods in rock mechanics. Discrete element approaches are computationally expensive as they involve the interaction of multiple discrete bodies with continuously changing contacts. Therefore, it is very important to ensure that the method selected for the analysis is computationally efficient. In this research, a general assessment of DDA and DEM is performed from a computational efficiency perspective, and relevant enhancements to DDA are developed. The computational speed of DDA is observed to be considerably slower than DEM. In order to identify reasons affecting the computational efficiency of DDA, fundamental aspects of DDA and DEM are compared which suggests that they mainly differ in the contact mechanics, and the time integration scheme used. An in-depth evaluation of these aspects revealed that the openclose iterative procedure used in DDA which exhibits highly nonlinear behavior is one of the main reasons causing DDA to slow down. In order to improve the computational efficiency of DDA, an alternative approach based on a more realistic rock joint behavior is developed in this research. In this approach, contacts are assumed to be deformable, i.e., interpenetrations of the blocks in contact are permitted. This eliminated the computationally expensive open-close iterative procedure adopted in DDA-Shi and enhanced its speed up to four times. In order to consider deformability of the blocks in DDA, several approaches are reported. The hybrid DDA-FEM approach is one of them, although this approach captures the block deformability quite effectively, it becomes computationally expensive for large-scale problems. An alternative simplified uncoupled DDA-FEM approach is developed in this research. The main idea of this approach is to model rigid body movement and the block internal deformation separately. Efficiency and simplicity of this approach lie in keeping the DDA and the FEM algorithms separate and solving FEM equations individually for each block. Based on a number of numerical examples presented in this dissertation, it is concluded that from a computational efficiency standpoint, the implicit solution scheme may not be appropriate for discrete element modelling. Although for quasi-static problems where inertia effects are insignificant, implicit schemes have been successfully used for linear analyses, they do not prove to be advantageous for contact-type problems even in quasi-static mode due to the highly nonlinear behavior of contacts.

Esse trabalho trata do problema de interação dinâmica entre veículos de carga e estruturas de pontes rodoviárias, incluindo o aprimoramento de um modelo veicular de oito graus de liberdade usualmente utilizado na modelagem de veículos classe 3C, introduzindo o nono grau de liberdade, referente à rotação em torno de seu eixo longitudinal ou movimento roll. Foram calculados os carregamentos provenientes do veículo modelado sobre pavimento inicialmente indeslocável, com perfis iguais ou distintos de rugosidade e diferentes sob cada linha de pneus, assim como a participação da energia modal do veículo para cada caso. Tais carregamentos foram condensados estaticamente e aplicados em modelo estrutural simplificado (unifilar) de uma ponte em seção celular, visando a identificar as flutuações dos esforços de torção provenientes da diferença de perfil de rugosidade sob cada linha de pneus do veículo estudado. Ainda foram confrontados resultados para duas situações de tráfego, sendo a primeira para veículo isolado trafegando sobre estrutura e a segunda para um comboio de veículos. Também, verificou a aproximação implícita na adoção de pavimento indeslocável para a obtenção dos esforços da interação veículo-pavimento, utilizando um método iterativo até que se garantisse convergência para os deslocamentos. / This work is concerned with the problem of dynamic interaction between heavy vehicles and bridges structures and also with the improvement of an eight-degree-of-freedom model of a 3C class vehicle, by introducing the ninth degree of freedom referring to the rotation about the vehicle longitudinal axis, or roll movement. The loads applied by the vehicle to the bridge deck were evaluated, assuming initially a rigid structure under the pavement, for both equal and distinct roughness profiles under each tire line, as well as the vehicle modal energy participation for each case. Such loads were statically condensed and applied to a simplified (unifilar) structural model of a girder box bridge, aiming at estimating the fluctuation of the torsion moments due to the differences in the roughness profiles under each tire line. The differences in the dynamic response were evaluated considering two traffic situations, namely a single vehicle or an ensemble of vehicles moving along the bridge. It was further checked the approximation implied in the assumption of a rigid structure under the pavement for the evaluation of the vehicle-structure interaction loads, by means of an iterative procedure until convergence was obtained for the displacements. Besides, it was compared the dynamic responses considering two different traffic situations. The first situation is a unique vehicle moving on a bridge whereas the second is a train of vehicle moving on the bridge. Ahead, it was verified the error in adopt the hypothesis of unmoved pavement in the vehicles model to obtain iteration forces pavement-vehicle, using an iterative methodology to rebuild the original vehicles displacement.

Orange, turqoise, apricot, brown, dirt, soil, water, sky and sulfur were my first bricks while building this collection. Ifound them in the pictures I took in Yellowstone, in the summer of 2010. While being in Yellowstone I thought aboutthe artist Georgia O´Keffee, an artist I’ve long liked. The landscape of Yellowstone reminded me about her landscapepaintings so I researched her life and work. She was a genuine feminist without saying it, she just lived like she wasequal to other women and men. This led me to a book about forgotten goddesses where I found references todrapings that I’ve developed and interspersed with flat pattern cutting. One of my key objectives, in this project andother projects, has been to push the limits of menswear towards feminine elements. I believe that there’s a certainreason why a woman can wear a suit without anyone looking twice but it’s very striking if a man wears a dress. Inthis collection I’ve looked into various reasons for this and I aim to let men dress the same way as women do aswell as the other way around. / Program: Modedesignutbildningen