La Corrélation d'Images Numériques (CIN) a été utilisée pour la première fois dans une galerie so... more La Corrélation d'Images Numériques (CIN) a été utilisée pour la première fois dans une galerie souterraine pour suivre les fissures de dessiccation pendant un cycle climatique annuel. Cette investigation expérimentale a été effectuée sur une zone d'étude de 344×275 mm², située sur le front de galerie EST-96 de la station expérimentale de Tournemire, pendant laquelle le taux d'humidité relative (HR) et la température (T) ont été mesurées en continu pendant plus d'une année (de Mars 2011 à Mars 2012). Nos résultats démontrent la capacité de la méthode non-invasive (CIN) pour surveiller l'ouverture et la fermeture des fissures de dessiccation pendant plus d'un an. Par ailleurs, notre étude donne les résultats suivants phénoménologiques. Tout d'abord, comme on l'observe dans le laboratoire, les déformations hydriques étaient anisotropes, les déformations perpendiculaires aux fissures de dessiccation étaient presque homogènes et beaucoup plus grandes que celles qui sont parallèles aux mêmes fissures. Deuxièmement, les changements dans les ouvertures de fissures calculées à partir des champs de déplacement (avec une précision d'environ 26,9 µm) et les champs de déformations sont clairement corrélés et concomitantes à des changements de HR et T (avec 25%<HR<99% et 6°C<T<14°C). De plus, les fissures principales de dessiccation étaient sub-horizontales et associées à la direction des plans de stratification, notre travail a démontré l'existence de fissures sub-verticales.
ABSTRACT This study reports on the digital image correlation (DIC) procedure and its limitation i... more ABSTRACT This study reports on the digital image correlation (DIC) procedure and its limitation in the case of fracture analysis. A comparison of three different algorithms was carried out for the case of crossing cracks. An improvement of the DIC procedure was proposed to solve the uncertainty problems at the vicinity of the junction of two cracks. This procedure was proposed to perform an evaluation of the displacement when multiple cracks are present in the subset. It was developed using classical minimization process, including Heaviside functions in the kinematical field representation. Some tests were performed to demonstrate the performances of this new algorithm. An application of the multiple fractures on Argillite rock is shown to validate the efficiency and the robustness of the proposed method.
International Workshop on Geomechanics and Energy, 2013
Digital image correlation was used for the first time in an underground gallery to monitor the ar... more Digital image correlation was used for the first time in an underground gallery to monitor the argillaceous rock deformations during an annual climatic cycle. This experimental in situ investigation was carried out on a study area of 34.4×27.5 cm², located on the East96 gallery front at the Tournemire experimental station, during which the relative humidity (RH) and temperature (T) were continuously measured for more than one year and fluctuate naturally.Our results demonstrate the ability of the non-invasive DIC method to monitor clay-rock strains and the opening and closure of desiccation cracks. Moreover, our study provides the following results. First, the hydric strains were anisotropic; the strains perpendicular to the desiccation cracks were almost homogeneous and much larger than those parallel to the same cracks. Second, the changes in crack apertures calculated from the displacement fields and the strain fields were clearly correlated and concomitant with changes in RH and T. Third, contrary to direct measurements acquired at the Mont-Terri site, the crack apertures of the desiccation cracks were reversible after one year of data acquisition. Moreover, although the main desiccation cracks were sub-horizontal and associated with the direction of bedding planes, our work demonstrated the existence of sub-vertical cracks.
ABSTRACT Digital image correlation (DIC) was used for the first time in an underground gallery to... more ABSTRACT Digital image correlation (DIC) was used for the first time in an underground gallery to monitor desiccation cracks during an annual climatic cycle. This experimental in situ investigation was carried out on a study area of 344×275 mm², located on the East96 gallery front at the Tournemire experimental station, during which the relative humidity (RH) and temperature (T) were continuously measured for more than one year (from March 2011 to March 2012). Our results demonstrate the ability of the non-invasive DIC method to monitor the opening and closure of desiccation cracks for more than one year. Moreover, our study provides the following phenomenological results. First, as observed in the laboratory, the hydric strains were anisotropic; the strains perpendicular to the desiccation cracks were almost homogeneous and much larger than those parallel to the same cracks. Second, the changes in crack apertures calculated from the displacement fields (at an accuracy of approximately 26.9 μm) and the strain fields were clearly correlated and concomitant with changes in RH and T (with 25%&lt;RH&lt;99% and 6°C&lt;T&lt;14°C). Moreover, although the main desiccation cracks were sub-horizontal and associated with the direction of bedding planes, our work demonstrated the existence of sub-vertical cracks.
This study reports on the digital image correlation (DIC) procedure and its limitation in the cas... more This study reports on the digital image correlation (DIC) procedure and its limitation in the case of fracture analysis. A comparison of three different algorithms was carried out for the case of crossing cracks. An improvement of the DIC procedure was proposed to solve the uncertainty problems at the vicinity of the junction of two cracks. This procedure was proposed to perform an evaluation of the displacement when multiple cracks are present in the subset. It was developed using classical minimization process, including Heaviside functions in the kinematical field representation. Some tests were performed to demonstrate the performances of this new algorithm. An application of the multiple fractures on Argillite rock is shown to validate the efficiency and the robustness of the proposed method.
RÉSUMÉ — La Corrélation d'Image Numérique (CIN) a été utilisée dans une galerie souterraine p... more RÉSUMÉ — La Corrélation d'Image Numérique (CIN) a été utilisée dans une galerie souterraine pour étudier les fissures de dessiccation pendant un cycle climatique annuel. Cette expérience expérimentale a été effectuée sur une zone d'étude de 344x275 mm², situé sur le front de la galerie EST96 dans la station expérimentale de Tournemire où l'humidité relative (HR) et la température (T) ont été mesurées en continu pendant plus d'un an (à partir de Mars 2011 à Mars 2012). Nos résultats ont montré la capacité de la méthode non invasive (CIN) pour quantifier (a) les déformations spatialisées de la roche argileuse et (b) les ouvertures et les fermetures de fissures de dessiccation pendant plus d'un an. Notre étude donne les résultats suivants : tout d'abord, comme on l'observe sur des échantillons carottés de roche argileuse, les déformations hydriques étaient anisotropes: les déformations perpendiculaires aux fissures de dessiccation étaient presque homogènes e...
La Corrélation d'Images Numériques (CIN) a été utilisée pour la première fois dans une galerie so... more La Corrélation d'Images Numériques (CIN) a été utilisée pour la première fois dans une galerie souterraine pour suivre les fissures de dessiccation pendant un cycle climatique annuel. Cette investigation expérimentale a été effectuée sur une zone d'étude de 344×275 mm², située sur le front de galerie EST-96 de la station expérimentale de Tournemire, pendant laquelle le taux d'humidité relative (HR) et la température (T) ont été mesurées en continu pendant plus d'une année (de Mars 2011 à Mars 2012). Nos résultats démontrent la capacité de la méthode non-invasive (CIN) pour surveiller l'ouverture et la fermeture des fissures de dessiccation pendant plus d'un an. Par ailleurs, notre étude donne les résultats suivants phénoménologiques. Tout d'abord, comme on l'observe dans le laboratoire, les déformations hydriques étaient anisotropes, les déformations perpendiculaires aux fissures de dessiccation étaient presque homogènes et beaucoup plus grandes que celles qui sont parallèles aux mêmes fissures. Deuxièmement, les changements dans les ouvertures de fissures calculées à partir des champs de déplacement (avec une précision d'environ 26,9 µm) et les champs de déformations sont clairement corrélés et concomitantes à des changements de HR et T (avec 25%<HR<99% et 6°C<T<14°C). De plus, les fissures principales de dessiccation étaient sub-horizontales et associées à la direction des plans de stratification, notre travail a démontré l'existence de fissures sub-verticales.
ABSTRACT This study reports on the digital image correlation (DIC) procedure and its limitation i... more ABSTRACT This study reports on the digital image correlation (DIC) procedure and its limitation in the case of fracture analysis. A comparison of three different algorithms was carried out for the case of crossing cracks. An improvement of the DIC procedure was proposed to solve the uncertainty problems at the vicinity of the junction of two cracks. This procedure was proposed to perform an evaluation of the displacement when multiple cracks are present in the subset. It was developed using classical minimization process, including Heaviside functions in the kinematical field representation. Some tests were performed to demonstrate the performances of this new algorithm. An application of the multiple fractures on Argillite rock is shown to validate the efficiency and the robustness of the proposed method.
International Workshop on Geomechanics and Energy, 2013
Digital image correlation was used for the first time in an underground gallery to monitor the ar... more Digital image correlation was used for the first time in an underground gallery to monitor the argillaceous rock deformations during an annual climatic cycle. This experimental in situ investigation was carried out on a study area of 34.4×27.5 cm², located on the East96 gallery front at the Tournemire experimental station, during which the relative humidity (RH) and temperature (T) were continuously measured for more than one year and fluctuate naturally.Our results demonstrate the ability of the non-invasive DIC method to monitor clay-rock strains and the opening and closure of desiccation cracks. Moreover, our study provides the following results. First, the hydric strains were anisotropic; the strains perpendicular to the desiccation cracks were almost homogeneous and much larger than those parallel to the same cracks. Second, the changes in crack apertures calculated from the displacement fields and the strain fields were clearly correlated and concomitant with changes in RH and T. Third, contrary to direct measurements acquired at the Mont-Terri site, the crack apertures of the desiccation cracks were reversible after one year of data acquisition. Moreover, although the main desiccation cracks were sub-horizontal and associated with the direction of bedding planes, our work demonstrated the existence of sub-vertical cracks.
ABSTRACT Digital image correlation (DIC) was used for the first time in an underground gallery to... more ABSTRACT Digital image correlation (DIC) was used for the first time in an underground gallery to monitor desiccation cracks during an annual climatic cycle. This experimental in situ investigation was carried out on a study area of 344×275 mm², located on the East96 gallery front at the Tournemire experimental station, during which the relative humidity (RH) and temperature (T) were continuously measured for more than one year (from March 2011 to March 2012). Our results demonstrate the ability of the non-invasive DIC method to monitor the opening and closure of desiccation cracks for more than one year. Moreover, our study provides the following phenomenological results. First, as observed in the laboratory, the hydric strains were anisotropic; the strains perpendicular to the desiccation cracks were almost homogeneous and much larger than those parallel to the same cracks. Second, the changes in crack apertures calculated from the displacement fields (at an accuracy of approximately 26.9 μm) and the strain fields were clearly correlated and concomitant with changes in RH and T (with 25%&lt;RH&lt;99% and 6°C&lt;T&lt;14°C). Moreover, although the main desiccation cracks were sub-horizontal and associated with the direction of bedding planes, our work demonstrated the existence of sub-vertical cracks.
This study reports on the digital image correlation (DIC) procedure and its limitation in the cas... more This study reports on the digital image correlation (DIC) procedure and its limitation in the case of fracture analysis. A comparison of three different algorithms was carried out for the case of crossing cracks. An improvement of the DIC procedure was proposed to solve the uncertainty problems at the vicinity of the junction of two cracks. This procedure was proposed to perform an evaluation of the displacement when multiple cracks are present in the subset. It was developed using classical minimization process, including Heaviside functions in the kinematical field representation. Some tests were performed to demonstrate the performances of this new algorithm. An application of the multiple fractures on Argillite rock is shown to validate the efficiency and the robustness of the proposed method.
RÉSUMÉ — La Corrélation d'Image Numérique (CIN) a été utilisée dans une galerie souterraine p... more RÉSUMÉ — La Corrélation d'Image Numérique (CIN) a été utilisée dans une galerie souterraine pour étudier les fissures de dessiccation pendant un cycle climatique annuel. Cette expérience expérimentale a été effectuée sur une zone d'étude de 344x275 mm², situé sur le front de la galerie EST96 dans la station expérimentale de Tournemire où l'humidité relative (HR) et la température (T) ont été mesurées en continu pendant plus d'un an (à partir de Mars 2011 à Mars 2012). Nos résultats ont montré la capacité de la méthode non invasive (CIN) pour quantifier (a) les déformations spatialisées de la roche argileuse et (b) les ouvertures et les fermetures de fissures de dessiccation pendant plus d'un an. Notre étude donne les résultats suivants : tout d'abord, comme on l'observe sur des échantillons carottés de roche argileuse, les déformations hydriques étaient anisotropes: les déformations perpendiculaires aux fissures de dessiccation étaient presque homogènes e...
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