463 research outputs found
Advanced Underground Space Technology
The recent development of underground space technology makes underground space a potential and feasible solution to climate change, energy shortages, the growing population, and the demands on urban space. Advances in material science, information technology, and computer science incorporating traditional geotechnical engineering have been extensively applied to sustainable and resilient underground space applications. The aim of this Special Issue, entitled “Advanced Underground Space Technology”, is to gather original fundamental and applied research related to the design, construction, and maintenance of underground space
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Structural behaviour of concrete segmental lining tunnels: towards design optimisation
The deployment of engineering models and design methods divorced from the effect that mechanised shield tunnelling with tunnel boring machines (TBMs) has on concrete segmental linings (CSLs) can lead to either material waste or structural damage within the tunnel design life. Most research to date on CSL behaviour during construction neglects the sequential ring loading and TBM-lining transverse interactions, which this thesis proved to be key in the short and long term behaviour of CSLs and whose study is essential if the design and maintenance of CSL structures is ever to be optimised.
This thesis investigates the longitudinal and transverse behaviour of CSL structures simultaneously backfilled with bicomponent grouts (BGs) during tunnelling, and how this early response influences long term behaviour. The research work is drawn on three pillars that enable cross-validation of conclusions: analytical models, three-dimensional numerical simulations and the interpretation of the Crossrail’s Thames tunnel (CTT) field data, which included distributed fibre optic strain (DFOS) data. A theoretical framework ranging from construction loading scenarios to the mechanisms underlying structural damage is described for the future development of limit state design methods. Analytical models of longitudinal behaviour are also proposed. The study of joint geometries, temporary spear bolts and DFOS sensing in CSL construction monitoring is included as ancillary research.
The solution developed for a sequential elastic rod subjected to a trilinear temperature profile and in shear interaction with the elastic ground predicts accurately the early tunnel pre-stressing relaxation caused by grout hardening, e.g. ≈50% in the CTT. The proposed sequential elastic beam model, which incorporates the effects of stage-varying net TBM moments, transverse loads and lining pressure gradients within the tunnel unsupported length, estimates satisfactorily the history of tunnel beam response during construction for a realistic expression of the lining stiffness. A potential damage assessment method for the early detection of tunnel sections prone to ring joint damage was proposed.
The TBM-lining transverse interaction determines the CSL ring behaviour at the early stages of tunnelling. The ring response resultant from this interaction is irrecoverable and contributes to the long term total deformations and internal forces; in tunnels excavated in grounds with Ko≈1, it becomes the major source of ring distortion. The main transverse actions are the sealing pressures, which are inversely related to the tail clearance, and the transverse load of oblique hydraulic jacks. When the non-bedded rings are eccentric with respect to the shield tail, the ring distortion increases the risk of cracking near the rear corners and spalling at the ram pad interspaces of constrained segments. The ring distortion is directly related to the pressure gradients, the unsupported length and the ring flexibility. When individual segments rotate outwards under the action of transverse ram loads, e.g. the outer springline segment during pronounced TBM steering around a horizontal curve, the localised action of the sealing pressures can result in longitudinal cracking at the intrados of the segment front.
This study represents a qualitative leap towards the optimisation of CSL design, shifting the attention of researchers and designers to TBM-lining transverse interactions as the most determinant factor of structural response during construction in CSLs simultaneously backfilled with BGs.Engineering and Physical Science Research (EPSRC): grant number 135734
Cost studies of multipurpose large launch vehicles. Volume 3 - Resource implications Final report
Manpower resources and costs for multistage, multipurpose large launch vehicle
Análise da subsidencia xerada pola escavación de dous túneles utilizando máquinas tuneladoras EPB (Earth Pressure Balance). Estudio da relación entre as variables de perforación e os asentamentos inducidos.
Currently the development in the use of underground space in urban environments is being instrumental in the planning and management of cities.
This use of underground space arises as a result of the growth of cities, demanding infrastructure that accommodate and respond to all that the city needs demand.
One of the key pieces to carry out sustainable urban development is improving its transport and communication. For this, new rail and road networks are being designed and implemented using the latest technologies in underground excavations.
An example of development of underground space for improving the transport network is the one that is running in London; Crossrail.
Crossrail is the largest underground construction project that is currently underway in Europe. It is the development of a new railway network that would connect the West Zone (Reading) with the East (Abbey Wood and Shenfield) London area, through the British capital.
A total of 42 km of tunnels have been excavated tunnel boring machines used. 10 sections of tunnels have been dug with 8 TBMs that have passed under the city, sharing space with the underground network in London, the Thames river, large Racacielos, old foundations, stations, collectors and underground rivers at depths up 40 m. This urban environment requires absolute control of the subsidence that may arise.
The objective is to determine the influence that the excavation of two tunnels by EPB, has generated over the seats and set a proceeding that, depending on the evolution of the excavation, anticipate the possibility of generating a seat surface.Actualmente el desarrollo en el uso del espacio subterraneo en entornos urbanos esta siendo pieza clave en la planificacion y gestion de las ciudades.
Este uso del espacio subterrano surge como la consecuencia del crecimiento de las ciudades, demandando infraestructuras que den cabida y respuesta a todas las necesidades que la ciudad demanda.
Una de las piezas clave para poder llevar a cabo un desarrollo urbano sostenible es la mejora de su red de transporte y comunicacion. Para ello, nuevas redes ferroviarias y viarias se estan diseñando y ejecutando, utilizando las ultimas tecnologias en excavaciones subterraneas.
Un ejemplo de desarrollo del espacio subterraneo para la mejora de la red de transporte es el que se esta ejecutando en Londres; Crossrail.
Crossrail es el mayor proyecto de construccion subterraneo que se esta realizando actualmente en Europa. Consiste en el desarrollo de una nueva red ferroviaria que conectara la la zona Oeste (Reading) con la zona Este (Abbey Wood y Shenfield) de Londres, atravesando la capital britanica.
Un total de 42 km de tuneles han sido excavados utilizado maquinas tuneladoras. 10 tramos de tuneles se han excavado con 8 tuneladoras que han pasado por debajo de la ciudad, compartiendo el espacio con la red de metro de Londres, el rio Thames, grandes racacielos, antiguas cimentaciones, estaciones, colectores y rios subterraneas a profundidades de hasta 40 m. Este entorno urbano exige un control absoluto de las subsidencias que se puedan generar.
El objetivo es determinar la influencia que la excavacion de dos tuneles mediante EPB, tiene sobre los asientos generados y establecer un procedimento que, en funcion de la evolucion de la excavacion, anticipe la posibilidad de generar un asiento en superficie.Actualmente o desenvolvemento no uso do espazo subterráneo en ambientes urbanos está fundamental para a planificación e xestión das cidades.
Este uso subterrano espazo xorde como resultado do crecemento das cidades, esixindo infraestrutura que acomodar e responder a todo o que a cidade ten demanda.
Unha das pezas clave para levar a cabo o desenvolvemento urbano sostible e mellorar o seu transporte e comunicación. Para iso, novas redes ferroviarias e estradas están sendo deseñados e implementados utilizando as recentes tecnoloxías en escavacións subterráneas.
Un exemplo de desenvolvemento do espazo subterráneo para mellorar a rede de transporte é o que está a ser executado en Londres; Crossrail.
Crossrail é o maior proxecto de construción subterránea que está actualmente en curso en Europa. É o desenvolvemento dunha nova rede ferroviaria que ligaría a Zona Oeste (Reading) co Oriente (Abbey Wood e Shenfield) Área de Londres, a través da capital británica.
Un total de 42 km de túneles foron excavados túnel máquinas de perforación usados. 10 seccións de túneles foron escavados con 8 TBM que pasaron baixo a cidade, dividindo espazo coa rede de metro de Londres, o río Támesis, gran Racacielos, fundacións antigas, estacións, recolectores e ríos subterráneos en profundidades de ata 40 m. Este ambiente urbano esixe control absoluto da subsidência que poida xurdir.
O obxectivo é determinar a influencia que a escavación de túneles por dous EPB, xerou ao longo dos asentos e establecer un proceso que, dependendo da evolución da excavación, prevista a posibilidade de xerar unha superficie de asento
Geotechnical design and construction automation in Taiwan
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996.Includes bibliographical references (leaves 122-125).by Berlin Wu.M.S
Tunnelling
Tunnelling has become a fragmented process, excessively influenced by lawyers'notions of confrontational contractual bases. This prevents the pooling of skills, essential to the achievement of the promoters' objectives. Tunnelling: Management by Design seeks the reversal of this trend. After a brief historical treatment of selected developments, t
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