During soft ground tunnel construction, if the face pressure of a tunnel boring machine is not strictly controlled, excessive ground movements will propagate vertically upwards causing significant damage to adjacent buried infrastructure and surface structures. In order to investigate the face pressure - ground deformation relationship for tunnels in sands, the construction process was modelled using the technique of geotechnical centrifuge modelling and the resulting ground deformations were recorded using digital image correlation. In these tests a unique tunnel face boundary condition was developed which allowed the boundary condition to be initially set as a zero strain condition before it was transformed into a load-controlled boundary to investigate the instability of the face. Tests were preformed at four different burial depths in dry sand, corresponding to cover depths of 0.5, 1, 1.5, and 2 times the tunnel diameter. These results indicate that the face pressure at failure is largely independent of burial depth over the values tested. The ground deformation at the onset of tunnel face instability was found to be very small, and once initiated, the zone of ground deformations was observed to propagate upwards in a narrow chimney in front of the tunnel until it reached the ground surface causing subsidence. Further tests investigated the variation in ground deformations to be expected if a tunnel were to be passing through more complex ground conditions, including unsaturated sand, saturated sand, and the unique case of sand / clay mixed ground conditions. Ground deformations at tunnel face instability were much lower for the case of unsaturated sand, than for either the saturated or dry cases which showed broadly similar responses. In the mixed ground condition of a clay layer over topping a sand layer, the clay layer was found to only influence the tunnel face pressure – deformation response if the bottom of the clay layer was closer than 0.5 diameters above the tunnel crown. / Thesis (Master, Civil Engineering) -- Queen's University, 2007-12-20 15:09:06.156

No description available.

Due to space limitations in urban areas, underground construction has become a common practice worldwide. When using deep excavations, excessive lateral movements are a major concern because they can lead to significant displacements and rotations in adjacent structures. Therefore, accurate predictions of lateral wall deflections and surface settlements are important design criteria in the analysis and design of excavation support systems. This research shows that the current design methods, based on plane strain analyses, are not accurate for designing excavation support systems and that fully three-dimensional (3D) analyses including wall installation effects are needed. A complete 3D finite element simulation of the wall installation at the Chicago and State Street excavation case history is carried out to show the effects of modeling: (i) the installation sequence of the supporting wall, (ii) the excavation method for the wall, and (iii) existing adjacent infrastructure. This model is the starting point of a series of parametric analyses that show the effects of the system stiffness on the resulting excavation-related ground movements. Furthermore, a deformation-based methodology for the analysis and design of excavation support systems is proposed in order to guide the engineer in the different stages of the design. The methodology is condensed in comprehensive flow charts that allow the designer to size the wall and supports, given the allowable soil distortion of adjacent structures or predict ground movements, given data about the soil and support system.

Natural Hazards are a risk to buried gas pipeline infrastructure, but these risks are difficult to assess and quantify. This can often lead to the risks not being properly identified by pipeline owners. The risk to pipelines within landslide areas are particularly difficult to assess given the complex nature of landslide movements and the soil-pipeline interaction mechanisms imposing loads on a pipeline. This thesis research examines the relationship between ground movements and strains/stresses in buried pipelines through field measured ground movements and in-situ measured pipe strains/stresses. The pipe stresses and strains are then used to estimate probability of pipeline failure and risk based on RBDA limit states approaches. Within Manitoba Hydro’s pipeline network, three at-risk landslide areas (riverbank and deep river valleys) were selected for detailed studies. A field investigation and monitoring program was undertaken to assess possible sources of load and stresses on pipelines. Soil, ground, and pipe instrumentation were installed at the sites and monitored over a four year period. Monitoring results identified soil near the pipeline does not freeze, and ground movements at valley sites are slow moving (<50 mm/year) landslides. The monitoring results also showed pipe stresses and behaviour were affected by backfilling, changes in river levels, thermal affects, soil-pipe relaxation, and ground movements. Pipe push tests were conducted in conjunction with FEM modelling to examine pipe adhesion and to possible explain the pipe behaviour observed. Several ultimate and serviceability limit states pipe failure modes were assessed using the measured pipe stresses. Statistical analysis was undertaken to calculate the probability of pipeline failure for the various limit states failure modes and compared against limit states targets for several scenarios (backfill loads, initial stress-state of the pipeline, other pipelines within Manitoba Hydro network). Overall, the probability of failure estimates were generally insignificant or low due to a postulated soil-pipe relaxation mechanism which is causing a repeated release in longitudinal pipe stresses as the landslide continues to accumulate ongoing ground movements. Three mechanisms are presented and discussed. The statistical analysis indicate pipelines within Manitoba Hydro’s network may exceed limit states targets for yielding and local buckling depending on the loading scenario and the class of the pipeline within the landslide area. The outcome of the research was used to develop a risk managements system to examine geotechnical hazards within Manitoba Hydro’s pipeline network. Specifically, risks associated with ground movements along natural slopes and at river crossings are examined within the system. / October 2016

Development in urban areas around the world has steadily increased in recent years. This rapid development has not been matched by the ever decreasing open space commonly associated with urban centers. Vertical construction, thus, lends itself a very useful solution to this problem. Deep excavation is often required for urban construction. Unfortunately, the ground movements associated with deep excavation can result in damage to adjacent buildings. Thus, it is critically important to accurately predict the damage potential of nearby deep excavations and designing adequate support systems. A new design method is proposed, as an attempt, to address the problem. The method is semi-empirical and directly links excavation-induced distortions experienced by nearby buildings and the components of the excavation support system. Unlike, the traditional limit equilibrium approach, the method is driven by the distortions in adjacent buildings. It goes further to propose a preliminary cost chart to help designers during the design phase. The benefit is that initial cost is known real time and will help speed up making business decisions. A new design flowchart is proposed to guide the designer through a step-by-step procedure. The method is validated using 2D Plaxis (the finite element program) simulation. Though the nature of deep excavation is three-dimensional, a plane strain condition is valid when the length of the excavation is long. Hence, two-dimensional finite element simulation was considered appropriate for this effort. Five hypothetical cases were compared and the model performed very well. The lack of available literature on this approach made verification difficult. It is hoped that future case histories will be used to ascertain the veracity of the deformation-based design method.

This diploma thesis discusses and compares the current technologies and systems that are used to monitor and control movements on the airport surface. The paper presents the basic characteristics, operational principles and possibilities. Comparison provides an overview of their strengths and limitations in operational use. It also deals with this issue at the Ostrava Leos Janacek Airport, describes current situation and suggests how to solve problems associated with the introduction of CAT III precision approach and landing as well as monitoring and controlling of movements on the airfield under poor weather conditions.

Das Institut für Markscheidewesen und Geodäsie der TU Bergakademie Freiberg beschäftigt sich bereits seit vielen Jahren mit der Analyse und dem Monitoring der vertikalen Bodenbewegungen im ehemaligen Steinkohlerevier Oelsnitz/Erzgebirge. Aktuelle Bestrebungen gehen dahin, die Potentiale der Radarinterferometrie zur Detektion vertikaler Bodenbewegungen bestmöglich auszunutzen um zukünftig, im Vergleich zu Nivellement Messungen in großen zeitlichen Abständen, auch zeitlich besser aufgelöste Aussagen zur Bewegungsdynamik zu erhalten. Nach einer grundsätzlichen Darstellung des Ablaufs einer PSI-Analyse unter Nutzung weitgehend freier Softwarelösungen, werden am Beispiel des Oelsnitzer Reviers verschiedene aus der Anwendung des Verfahrens resultierende praktische Fragestellungen analysiert. / The Institute for Mine Surveying and Geodesy of the TU Bergakademie Freiberg has been working for many years on the analysis and monitoring of vertical ground movements in the former coal mine area Oelsnitz/Erzgebirge. Recent efforts are aimed at making the best possible use of the potentials of radar interferometry for the detection of these vertical ground movements. In the future, for example, it would be possible to obtain temporally better-resolved statements on the dynamics of ground movements in comparison to levelling measurements at long time intervals. After a general presentation of the workflow of a PSI analysis using widely free software solutions, various practical questions resulting from the application of the method are analyzed using the example of the former mining area Oelsnitz/Erzgebirge.

Dans ce travail, les risques naturels considérés concernent des mouvements de terrains qui résultent de deux phénomènes principaux : retrait et gonflement des sols argileux et l'affaissement à grand rayon lié à la présence des cavités souterraines. Ceux-ci provoquent des tassements différentiels du sol qui génèrent des désordres sur les constructions environnantes : dégâts et fissuration des murs porteurs en maçonnerie, particulièrement aux angles du bâti. Ces dégradations structurales induisent des conséquences économiques importantes dans le cas des maisons individuelles ; elles résultent d'un manque de résistance des maçonneries, du peu de raideur de leur système de fondation et du peu d'efficacité de leur système de contreventement. Cette recherche a pour objectif d'analyser la vulnérabilité du bâti et de proposer des méthodes de renforcement pour les constructions existantes ainsi que des recommandations de dimensionnement pour les constructions. Ces questions nécessitent une connaissance approfondie du phénomène des mouvements des terrains et des modalités de transfert de ces actions à une structure. Pour y répondre, quatre étapes principales ont été effectuées : une étude bibliographique, une analyse de l'interaction sol-structure, un développement d'une justification d'endommagement et d'une méthode de renforcement ou de dimensionnement ainsi qu'une analyse probabiliste des risques. L'étude bibliographique avec des analyses fonctionnelles et statistiques, d'abord, propose un profil de la maison sensible à l'aléa naturel et des cas typiques des désordres sur la construction. Le développement des modélisations par éléments finis ensuite permet d'étudier les phénomènes d'interaction sol-structure. L'analyse de l'interaction sol - structure, au moyen de modélisations par éléments finis, permet d'obtenir des sollicitations dans la maçonnerie. D'abord, des modèles analytique et numérique simplifiés ont été développés pour modéliser des structures simples telles une semelle filante, un système de semelles d'une fondation filante ou un mur en maçonnerie sur un sol élastique de type Winkler ou Boussinesq. Ensuite, des modélisations de structures plus complexes avec tous les éléments du bâti ont été effectuées en développant un code aux éléments finis particulier qui a permis de calculer des bâtiments en maçonnerie sur un sol de type Pasternak. En vue de développer une justification d'endommagement ainsi qu'une méthode de renforcement et de dimensionnement adaptée pour risque «mouvement de terrains », les travaux de recherche focalisent sur la distribution des sollicitations obtenues par des modélisations et analysent les domaines de validité de la démarche proposée par les Eurocodes EC6 et EC8 pour les murs de contreventement en maçonnerie confinée (chainée) ou armée. L'analyse probabiliste des risques, couplant les modèles aux éléments finis développés avec la méthode des simulations de Monte-Carlo, a permis d'étudier la vulnérabilité des maisons individuelles selon les caractéristiques structurales représentatives du bâti existant, dans les régions les plus touchées par les mouvements de terrains. Les résultats de cette analyse ont été unifiés, au sein d'une méthodologie globale de l'évaluation de la vulnérabilité de structures, à l'usage, d'une part, des pouvoirs publics dans l'établissement de cartographies SIG des risques, et d'autre part de la capacité des procédés de renforcement à l'usage des industries / In the present work, the considered natural hazards concern to ground movements resulting from two main phenomena : shrinkage and swelling of clay soils and ground subsidence due to the presence of underground cavities. These phenomena cause differential ground settlements which generate disorders on the structures erected in their neighborhood : damage and cracking of masonry load-bearing walls, especially at the building corners. These structural degradations cause important economic consequences and losses in the case of dwelling houses. These damages result from a lack of masonry resistance or a small stiffness of the foundation system as well as a limited effectiveness of bracing system.This research aims to analyze the vulnerability of buildings and to propose a reinforcement method for the existing constructions as well as design recommendations for structures. These topics require a thorough understanding of the ground movements phenomenon and their transfer as actions on a structure. For this purpose, four main steps were performed : a literature review, an analysis of soil-structure interaction, a development of a damage justification and a method for reinforcement or design, as well as a probabilistic analysis of risk.The literature review with functional and statistical analysis, as a first step, provides a profile of the house susceptible to natural hazard effects and typical cases of building disturbances. The development of finite element method is therefore considered in order to study soil-structure interaction.The analysis of the soil-structure interaction using finite element modeling provides stresses in the masonry. First, simplified analytical and numerical models have been developed for simple structures such as a strip footing, a system of strips foundation or a masonry wall lying on elastic soil (Winkler or Boussinesq). Afterwards, modeling of more complex structures with the whole building elements was made by developing a particular finite element code that allowed the calculation of masonry buildings on a Pasternak soil. To develop a damage justification as well as the reinforcement and design building methods suitable for risk of “ground movements”, this work focuses on the stresses distribution obtained by numerical models and analyzes the validity domain of the approach proposed by Eurocodes EC6 and EC8 for confined masonry or reinforced masonry. By coupling the developed finite element models with the Monte-Carlo method, the probabilistic analysis of risk allows to study the vulnerability of dwelling houses having representative structural characteristics of existing buildings, erected in areas that are the most affected by ground movements. The results of this analysis have been unified into a global methodology for assessing the vulnerability of structures. This methodology is used, in one hand, for the development of GIS mapping of risks and, in other hand, for the reinforcement processes

The topic of this thesis relates to the state-of-art technologies and systems used for airport ground movements monitoring and guidance. Emphasis is placed on mode S of SSR, its characteristics, applications and avionics requirements. This thesis further comprises analysis of Brno - Turany Airport and it presents a new multilateration system including economical analysis, which would be used for aerodrome ground movements monitoring.

Les structures en maçonnerie représentent une proportion importante des maisons individuelles et sont plus vulnérables notamment lorsqu'elles sont soumises à des mouvements de terrain. Pour faire face aux conséquences de ce problème, une plate-forme d'essais a été développée pour simuler des mouvements de terrain et leur effet sur des modèles de structure en surface. Ce travail de thèse s'appuie sur un modèle physique réduit et développe des méthodes d'évaluation des dommages des structures maçonnées à l'aide de l'expérimentation physique. Dans un premier temps, un modèle physique à échelle réduite sous gravité terrestre (1g) a été conçu pour reproduire ce phénomène. Ce modèle d'interaction sol-fondation-maçonnerie est à l'échelle de 1/40. Le sol analogique est constitué d'un sable de Fontainebleau. La fondation de la structure est fabriquée à partir de silicone liquide, et les murs en maçonnerie sont constitués de petits blocs en bois. Pour mesurer les champs de déplacement du sol et de la structure, une technique de corrélation d'images numériques (DIC) est utilisée. Des discussions à propos de l'usage de cette technique lors de la réalisation d'un essai, notamment la prise en compte des erreurs de mesures, ont été également abordées. Dans un deuxième temps, on évalue les dommages par les méthodes conventionnelles basées sur des indicateurs de dommages et des abaques. Ensuite, des nouveaux outils basés sur la technique DIC sont proposés pour réaliser une évaluation de dommages plus efficace, et plus aisée. Le premier outil se basant sur le modèle d'interaction sol-structure de Winkler permet d'identifier les modes de rupture dans la structure. Pour cela, le problème inverse de l'interaction sol-structure a été résolu et les modes de rupture du mur, basés sur les efforts internes, ont été identifiés. Ensuite, un modèle DIC-M est proposé pour reproduire les fissures dans la maçonnerie. Le point clé de ce modèle concerne les mouvements des blocs qui sont simulés par un système d'éléments distincts. Par ce moyen, la reproduction des fissures, puis l'identification et la quantification des fissures deviennent aisées. Plus précisément, un nouvel indicateur de dommages lié à la longueur des fissures permet de mieux quantifier les dommages et de cartographier les fissures. L'incertitude de mesure est déterminée par une simulation de Monte-Carlo des erreurs de déplacements. Dans un troisième temps, la performance des outils développés est évaluée au travers d'un exemple d'évaluation des dommages potentiels. Une maison individuelle en maçonnerie soumise aux mouvements de terrain a été étudiée à l'aide de l'expérimentation physique. Une campagne d'essais considérant les positions les plus sensibles par rapport à la cuvette d'affaissement est réalisée. L'évaluation du niveau de dommage a été réalisée à l'aide des mesures de déformations et des caractéristiques de fissures observées. La comparaison entre les méthodes conventionnelles et la méthode développée montre la pertinence de l'indicateur longueur des fissures, et cet indicateur peut être considéré comme un nouvel outil lors d'évaluation des dommages dans la pratique. Pour conclure, des recommandations opérationnelles ont été suggérées afin d'obtenir une meilleure estimation du niveau de dommages de la structure. / Masonry structures present a significant proportion of individual houses and are especially more vulnerable when subjected to ground movements. To deal with consequences of this problem, a test-platform has been developed in order to simulate ground movements and their effect on structure models on the surface. This thesis is based on a reduced physical model and develops damage assessment methods for masonry structures using physical modelling. Firstly, a small-scaled physical model under Earth's gravity (1g) has been developed to reproduce this phenomenon. This model of soil-foundation-masonry interaction has a scale factor of 1/40. The analogue soil consists of the Fontainebleau sand. The foundation part of the structure is made of liquid silicon and masonry walls are made from small wooden blocks. To measure displacements fields of the soil and the structure, a digital image correlation (DIC) technique is used. Discussions about the use of this technique when performing a test, especially the consideration of measurement errors, are also addressed. Secondly, we first assess the damage through conventional methods based on damage indicators and graphs. Then, new easy to use tools based on the DIC technique are proposed to carry out a more effective damage assessment. The first tool helps identify failure modes in the structure, based on the Winkler soil-structure interaction model. To do this, the inverse problem of soil-structure interaction is resolved, and the failure modes, based on internal forces, are identified. Then, a DIC-M model is proposed to reproduce the crack propagation in the masonry wall. The key point of this model consists in the simulation of the block movements in a discrete element system (DES). Consequently, cracks can appear easily, and then the crack identification and quantification become easier. More precisely, a new damage indicator related to the cumulated length of cracks allows to better quantify the damage and the cartography the cracks. The measurement uncertainty is determined by Monte-Carlo simulation. Thirdly, the performance of proposed tools is discussed through an example of assessing potential damages. An individual house in masonry subjected to ground movements was studied using physical experimentation. A test campaign related to the most sensitive positions of the structure with respect to the subsidence centre is performed. Damage assessment is conducted using deformation measurement and crack characteristics. The comparison between conventional and developed methods shows the relevance of the damage indicator related to the cumulated length of cracks, and this indicator can be considered as a new tool for damage assessment in practice. Finally, operational recommendations are suggested in order to obtain a better estimation of the damage level of the structure.