TY - GEN
T1 - Microstructural degradation of Maastrichtian limestones
AU - Ngan-Tillard, D. J.M.
AU - Verwaal, W.
AU - Maurenbrecher, P. M.
AU - Van Paassen, L. A.
PY - 2010/12/1
Y1 - 2010/12/1
N2 - The Maastrichtian in The Netherlands is composed of a series of calcarenites and calcisiltites with layers of flints. At some locations, boreholes have revealed the presence of carbonate sands rather than rock. Several scenarios are proposed to explain the observed lack of cohesion and better predict the spatial distribution of the carbonate sands in the Maastrichtian. A 3D Leica microscope, an Environmental Electronic Microscope (ESEM) and a desktop micro-Computerized Tomography scanner (micro-CT scan) have been used to characterize differences in the micro-structures of limestone and carbonate sands samples. Grain crushing, the presence of a mud matrix binding up grains and the lack of a well developed calcite fringe cementation are observed in the carbonate sands and not in the calcarenites. Degradation during core recovery cannot be excluded. Cone penetration and pressuremeter tests in between rigid layers are recommended to detect any layer with an extremely weak cementation and high deformability.
AB - The Maastrichtian in The Netherlands is composed of a series of calcarenites and calcisiltites with layers of flints. At some locations, boreholes have revealed the presence of carbonate sands rather than rock. Several scenarios are proposed to explain the observed lack of cohesion and better predict the spatial distribution of the carbonate sands in the Maastrichtian. A 3D Leica microscope, an Environmental Electronic Microscope (ESEM) and a desktop micro-Computerized Tomography scanner (micro-CT scan) have been used to characterize differences in the micro-structures of limestone and carbonate sands samples. Grain crushing, the presence of a mud matrix binding up grains and the lack of a well developed calcite fringe cementation are observed in the carbonate sands and not in the calcarenites. Degradation during core recovery cannot be excluded. Cone penetration and pressuremeter tests in between rigid layers are recommended to detect any layer with an extremely weak cementation and high deformability.
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M3 - Conference contribution
AN - SCOPUS:84859893593
SN - 9780415804813
T3 - Rock Engineering in Difficult Ground Conditions - Soft Rocks and Karst - Proceedings of the Regional Symposium of the International Society for Rock Mechanics, EUROCK 2009
SP - 321
EP - 326
BT - Rock Engineering in Difficult Ground Conditions - Soft Rocks and Karst - Proceedings of the Regional Symposium of the International Society for Rock Mechanics, EUROCK 2009
T2 - Regional Symposium of the International Society for Rock Mechanics: Rock Engineering in Difficult Ground Conditions - Soft Rocks and Karst, EUROCK 2009
Y2 - 29 October 2009 through 31 October 2009
ER -