http://hdl.handle.net/10045/2083 Thu, 23 May 2013 02:39:34 GMT 2013-05-23T02:39:34Z http://rua.ua.es:80/dspace/retrieve/19813/LogoINTERES.jpg http://hdl.handle.net/10045/2083 http://hdl.handle.net/10045/22915 Título: Forensic analysis of buildings affected by mining subsidence based on Differential Interferometry (Part III) Autor/es: Herrera García, Gerardo; Álvarez Fernández, Martina Inmaculada; Tomás Jover, Roberto; González Nicieza, Celestino; López Sánchez, Juan Manuel; Álvarez Vigil, Arturo Ernesto Resumen: This work presents a forensic analysis of buildings affected by mining subsidence, which is based on deformation data obtained by Differential Interferometry (DInSAR). The proposed test site is La Union village (Murcia, SE Spain) where subsidence was triggered in an industrial area due to the collapse of abandoned underground mining labours occurred in 1998. In the first part of this work the study area was introduced, describing the spatial and temporal evolution of ground subsidence, through the elaboration of a cracks map on the buildings located within the affected area. In the second part, the evolution of the most significant cracks found in the most damaged buildings was monitored using biaxial extensometric units and inclinometers. This article describes the work performed in the third part, where DInSAR processing of satellite radar data, available between 1998 and 2008, has permitted to determine the spatial and temporal evolution of the deformation of all the buildings of the study area in a period when no continuous in situ instrumental data is available. Additionally, the comparison of these results with the forensic data gathered in the 2005–2008 period, reveal that there is a coincidence between damaged buildings, buildings where extensometers register significant movements of cracks, and buildings deformation estimated from radar data. As a result, it has been demonstrated that the integration of DInSAR data into forensic analysis methodologies contributes to improve significantly the assessment of the damages of buildings affected by mining subsidence. Wed, 18 Apr 2012 00:00:00 GMT http://hdl.handle.net/10045/22915 2012-04-18T00:00:00Z http://hdl.handle.net/10045/21703 Título: Relationship between piezometric level and ground deformations measured by means of DInSAR in the Vega Media of the Segura River (Spain) Autor/es: Tomás Jover, Roberto; Márquez Moreno, Yolanda; López Sánchez, Juan Manuel; Delgado Marchal, José; Blanco Sánchez, Pablo; Mallorquí Franquet, Jordi J.; Navarrete, D.; Duque Biarge, Sergi Resumen: Differential SAR Interferometry (DInSAR) is a remote sensing method with the well demonstrated ability to monitor geological hazards like earthquakes, landslides and subsidence. Among all these hazards, subsidence involves the settlement of the ground surface affecting wide areas. Frequently, subsidence is induced by overexploitation of aquifers and constitutes a common problem that affects developed societies. The excessive pumping of underground water decreases the piezometric level in the subsoil and, as a consequence, increases the effective stresses with depth causing a consolidation of the soil column. This consolidation originates a settlement of ground surface that must be withstood by civil structures built on these areas. In this paper we make use of an advanced DInSAR approach - the Coherent Pixels Technique (CPT) [1] - to monitor subsidence induced by aquifer overexploitation in the Vega Media of the Segura River (SE Spain) from 1993 to the present. 28 ERS-1/2 scenes covering a time interval of about 10 years were used to study this phenomenon. The deformation map retrieved with CPT technique shows settlements of up to 80 mm at some points of the studied zone. These values agree with data obtained by means of borehole extensometers, but not with the distribution of damaged buildings, well points and basements, because the occurrence of damages also depends on the structural quality of the buildings and their foundations. The most interesting relationship observed is the one existing between piezometric changes, settlement evolution and local geology. Three main patterns of ground surface and piezometric level behaviour have been distinguished for the study zone during this period: 1) areas where deformation occurs while ground conditions remain altered (recent deformable sediments), 2) areas with no deformation (old and non-deformable materials), and 3) areas where ground deformation mimics piezometric level changes (expansive soils). The temporal relationship between deformation patterns and soil characteristics has been analysed in this work, showing a delay between them. Moreover, this technique has allowed the measurement of ground subsidence for a period (1993-1995) where no instrument information was available. Sun, 01 Jan 2006 00:00:00 GMT http://hdl.handle.net/10045/21703 2006-01-01T00:00:00Z http://hdl.handle.net/10045/21702 Título: Advanced interpretation of subsidence in Murcia (SE Spain) using A-DInSAR data – modelling and validation Autor/es: Herrera García, Gerardo; Fernández, J.A.; Tomás Jover, Roberto; Cooksley, Geraint; Mulas de la Peña, Joaquín Resumen: Subsidence is a natural hazard that affects wide areas in the world causing important economic costs annually. This phenomenon has occurred in the metropolitan area of Murcia City (SE Spain) as a result of groundwater overexploitation. In this work aquifer system subsidence is investigated using an advanced differential SAR interferometry remote sensing technique (A-DInSAR) called Stable Point Network (SPN). The SPN derived displacement results, mainly the velocity displacement maps and the time series of the displacement, reveal that in the period 2004–2008 the rate of subsidence in Murcia metropolitan area doubled with respect to the previous period from 1995 to 2005. The acceleration of the deformation phenomenon is explained by the drought period started in 2006. The comparison of the temporal evolution of the displacements measured with the extensometers and the SPN technique shows an average absolute error of 3.9±3.8 mm. Finally, results from a finite element model developed to simulate the recorded time history subsidence from known water table height changes compares well with the SPN displacement time series estimations. This result demonstrates the potential of A-DInSAR techniques to validate subsidence prediction models as an alternative to using instrumental ground based techniques for validation. Thu, 01 Jan 2009 00:00:00 GMT http://hdl.handle.net/10045/21702 2009-01-01T00:00:00Z http://hdl.handle.net/10045/21701 Título: Procedimiento gráfico para la obtención de los parámetros de corrección del SMR a través de la proyección estereográfica Autor/es: Tomás Jover, Roberto; Delgado Marchal, José; Cuenca Payá, Artemio Resumen: El Slope Mass Rating (SMR, Romana, 1985) constituye una clasificación geomecánica de uso muy extendido para la caracterización de taludes en roca. Se obtiene por adición al índice RMR básico, calculado a partir de valores característicos del macizo rocoso, de una serie de factores de corrección dependientes del paralelismo discontinuidad-talud, del buzamiento de las discontinuidades, del buzamiento relativo entre las discontinuidades y el talud, así como del método de excavación empleado. En este trabajo se propone un método gráfico que permite obtener los parámetros de corrección del SMR (F1, F2 y F3) representando en proyección estereográfica los planos de discontinuidad y del talud a estudiar.; Slope Mass Rating (SMR, Romana, 1985) is a very used geomechanic classification for the characterization of rock slopes. It is obtained adding to basic RMR index, calculated by characteristic values of the rock mass, several correction factors depending of the discontinuity-slope parallelism, discontinuity dip, relative dip between discontinuity and slope and the employed excavation method. In this work it is presented a graphical method that allow us to obtain correction parameters of the SMR (F1, F2 y F3) representing in stereographic projection the discontinuity and slope surfaces to study. Sat, 01 Jan 2005 00:00:00 GMT http://hdl.handle.net/10045/21701 2005-01-01T00:00:00Z