Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Hydraulic characterization of carbonatic rock |
| Abstract | The hydraulic conductivity, K(?), and the water retention, ?(h), are needed to predict the flow of water and solute transport in unsaturated porous media. During recent decades methods have been developed to determine these hydraulic properties for rock. We have developed a methodology, based on Wind's evaporation method for soils, to measure in the laboratory the water retention and hydraulic conductivity in coherent porous rock. This methodology requires matric potential and water content estimation at three depths of the rock sample during a transient evaporation process. We applied this methodology to calcarenite, a sedimentary carbonate rock of marine environment. Little compacted, with a granular skeleton constituted by equal quantities of lithoclasts and bioclasts soaked in a matrix, this rock is widely represented in the Mediterranean basin, and often constitutes a thick layer of the vadose zone. Samples of three different lithotypes of calcarenites have been used for the tests: two of them (lithotypes A and B) came from the same place but different depths and the third lithotype, M, from an outcrop in another area. The water retention curves show similar values near saturation, indicating similar total porosity for the different lithotypes. For matric potential below -20 cm the curves differ; at the same matric potential the water content of lithotype M exceeds that of lithotypes A and B; moreover, at higher matric potential the curve of M shows smaller slope than those of A and B. Therefore M has a greater water retention capacity and spread of pore-size distribution. The results for hydraulic conductivity show greater values for A and B than for M over the entire range of matric potential investigated, though at high water content the differences are small. Therefore the hydraulic behaviour of the analysed rocks is very similar near the saturation while it differs in unsaturated conditions. These considerations point out the need of accurate studies on unsaturated hydraulic behaviour of carbonatic rocks. |
| Source | EGS-AGU-EUG Joint Assembly -Quantifying soil structural effects on hydraulic and transport processes from the microscale to field observations, Nizza, 6-11 april |
| Year | 2003 |
| Type | Poster |
| Authors | (1) CAPUTO M.C., (2) BASILE A., (2) DE MASCELLIS R., (3) NIMMO J.R., (1) VURRO M., (4) WALSH N. |
| Text | 119133 2003 Hydraulic characterization of carbonatic rock 1 CAPUTO M.C., 2 BASILE A., 2 DE MASCELLIS R., 3 NIMMO J.R., 1 VURRO M., 4 WALSH N. 1 CNR IRSA 2 CNR ISAFOM 3 US Geology Survey 4 Dipartimento di Geologia e geofisica , UNIBA The hydraulic conductivity, K , and the water retention, h , are needed to predict the flow of water and solute transport in unsaturated porous media. During recent decades methods have been developed to determine these hydraulic properties for rock. We have developed a methodology, based on Wind s evaporation method for soils, to measure in the laboratory the water retention and hydraulic conductivity in coherent porous rock. This methodology requires matric potential and water content estimation at three depths of the rock sample during a transient evaporation process. We applied this methodology to calcarenite, a sedimentary carbonate rock of marine environment. Little compacted, with a granular skeleton constituted by equal quantities of lithoclasts and bioclasts soaked in a matrix, this rock is widely represented in the Mediterranean basin, and often constitutes a thick layer of the vadose zone. Samples of three different lithotypes of calcarenites have been used for the tests two of them lithotypes A and B came from the same place but different depths and the third lithotype, M, from an outcrop in another area. The water retention curves show similar values near saturation, indicating similar total porosity for the different lithotypes. For matric potential below 20 cm the curves differ; at the same matric potential the water content of lithotype M exceeds that of lithotypes A and B; moreover, at higher matric potential the curve of M shows smaller slope than those of A and B. Therefore M has a greater water retention capacity and spread of pore size distribution. The results for hydraulic conductivity show greater values for A and B than for M over the entire range of matric potential investigated, though at high water content the differences are small. Therefore the hydraulic behaviour of the analysed rocks is very similar near the saturation while it differs in unsaturated conditions. These considerations point out the need of accurate studies on unsaturated hydraulic behaviour of carbonatic rocks. EGS AGU EUG Joint Assembly Quantifying soil structural effects on hydraulic and transport processes from the microscale to field observations Nizza 6 11 april Poster Hydraulic characterization of carbonatic rock Poster_EGS_2003.pdf Poster angelo.basile BASILE ANGELO mariaclementina.caputo CAPUTO MARIA CLEMENTINA roberto.demascellis DE MASCELLIS ROBERTO michele.vurro VURRO MICHELE |