TUNNELS

Author: ASSIS E SILVA SILMARA CRISTINA DE.
Year: 2004.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: E.T.S.I DE CAMINOS, CANALES Y PUERTOS.
Place of preparation: E.T.S.I. DE CAMINOS, CANALES Y PUERTOS.

Summary: Making a review by the technical literature on the global stage has been verified that there are no jobs that correlations between different systems of treatments to protect ground foundations compared to the digging of tunnels. Because of this gap and the need felt by professionals in the engineering, it is proposed here to a study whose primary objective is to establish a procedure for calculating relative to treatment with jet-grouting prior to the digging of a tunnel considering different profiles ground based on previous theoretical study of the behavior of the pressures and movements on the surface induced by them. The design of treatments jet-grouting should focus depending on the quality of ground, trying to reproduce numerically their influence on the ground and the result of these operations in buildings nearby. First there was a theoretical review of the types of treatment of the land more employees: jet-grouting, injections and micropilotes, with special emphasis on engineering practice Spanish. It also provides, in Appendix I, a study conducted previously on the geology of the soil forming the ground of the city of Madrid, because the validation of the proposed methodology has been made considering real situations for the expansion Subway Madrid (1996-1999, 1999-2003). Once presented and discussed different injection techniques and improving the ground, the fundamental objective of the research has involved the development of a methodology for the numerical analysis of the treatment of the land through columns jet-grouting. In the process of study and development of this methodology have distinguished four phases: A-representation of models with a single column. B-Models with columns in which considers the presence of buildings on the surface. C-Analysis of the simulation of the effect of pressure on the ground to run the column jet-grouting. D-Definition of the "equivalent" in deformation, in order to take into account the effect of its construction in the field. To represent the effect of pressure on the ground, in the execution of columns jet-grouting, we used an increase in volume, which is an option available in the code Plaxis. Analysis of the pressure, surrounding the columns, this increase in volume (in the range recital) has helped define the width of a column equivalent with different elastic properties as we move away from the axis of the column. The definition of these areas has been possible from the relationship between pressure and the effective module edométrico for different tests edométricos in soils tosquizos Madrid (De la Fuente and Oteo, 1985). The development of this study, allows some recommendations regarding the calculation and design treatments columns dejet-grouting, both numerically and in the situation on a practical level. Note that the numerical methodology developed here, simulating the execution of columns jet-grouting, associated or not the existence of buildings and underground works is a three-dimensional problem, while the "approximation" we are making through a two-dimensional model. In order to verify the soundness of the proposed numerical methodology, this has been applied to actual cases, compared to the measures reported by the author of this research for the expansion of the Madrid Metro, particularly in Metrosur (tranche of Leganes and Alcorcón) and on the Line 8 (Paseo de La Habana), which involve working with the team of advisers of the Madrid Metro. It tries therefore numerically reproduce the 8 inf 4a5 cia treatment jet-grouting interacting with a tunnel on the ground and to quantify the outcome of these operations in the upcoming structures. Finally, it presents an approach to risk that for similar situations in the areas of Madrid, allows us to obtain an order of magnitude of the influence of treatment with columns jet-grouting in the environment closest depending on the quality of ground and pitch columns, as the treatment is far from the buildings.