Url https://www.cimne.com/sgp/rtd/Project.aspx?id=849
Project title Predicción de riesgo y diseño seguro en rocas anhydríticas Risk prediction and safe design in anhydritic rocks
Reference RTI2018-094226-J-I00
Principal investigator Anna RAMON TARRAGONA - aramon@cimne.upc.edu
Start date 01/09/2019 End date 31/08/2022
Coordinator CIMNE
Consortium members
Program P.E. de I+D+i Orientada a los Retos de la Sociedad Call Proyectos de I+D+i Retos investigación 2018
Subprogram Retos Investigación Category Nacional
Funding body(ies) MCIU Grant 191.180,00 €
Abstract Experience gained during the analysis of swelling phenomena which damaged Lilla tunnel and Pont de Candí Bridge in Spain, showed that expansions were a result of gypsum crystal growth (Alonso et al., 2013, Alonso and Ramon 2013, Ramon et al., 2017). Lilla tunnel and Pont de Candi viaduct belong to the high-speed railway Madrid-Barcelona. Both field cases involved the development of swelling strains in an active expanding layer in anhydritic rock where gypsum crystals precipitated in discontinuities under water saturated conditions. This experience and subsequent developments define the background and the previous knowledge to build up the research Project. The Project highlights aspects insufficiently known: The process of crystal growth in anhydritic claystones; the kinetics of gypsum precipitation in natural environments; the associated effect of chemical composition of rock/soil and water chemistry; the effect of rock mass structure (pore size distribution, presence of discontinuities) and the rock deformation and pressure against structures and their spatial distribution. Solving this imperfect knowledge is the first objective of the Project. The Project includes also the development of calculation methods accounting for the mentioned phenomena, the proposition of field and laboratory testing and design criteria for a minimization of risks. The Project is divided in four parts. A) A laboratory investigation designed to identify the relevance of the structure and mineralogy of the rock mass on the expansive process. Natural as well as artificial samples will be tested. Specially designed original testing arrangements will be used. A set of quality cores (120 mm diameter) recovered in Lilla tunnel and Pont de Candí is available in the UPC Geotechnical laboratory B) Development of a general computational tool, which includes the fundamental aspects namely: - A rock matrix interpreted by soluble and non-soluble minerals - Multiphase flow - The necessary transport equations for the soluble species - An elastoplastic model to describe mechanical behaviour - The development of discontinuities as a result of construction processes (i.e. excavations). C) The validation of the computational methods developed against monitoring data and additional information from Pont de Candí, Lilla tunnel and Ascó nuclear energy station. The three of them are well documented case histories. D) The proposition of geotechnical field investigations, design of structures (tunnels in particular) and construction processes to minimize risks of rock expansion and its effects.