PORE SIZES DISTRIBUTION OF UNCONSOLIDATED GEOMATERIALS

MARCOS MONTORO; LUCAS CERIONI; PUSIOL, DANIEL

Rio de Janeiro

Congreso; 18th ISMAR Meeting; 2013

International Society of Magnetic Resonance

Pore size and pore sizes distribution of soils and rocks control many hydraulic and mechanical properties of natural geomaterials such as hydraulic conductivity and shear resistance. Pore size and sizes distribution of rocks depend on their mineral composition and the geological processes involved in their formation, while for unconsolidated materials such as soils, depend on grain sizes, grain sizes distribution and overburden pressure. The aim of this project is to correlate transversal relaxation time (T2) with grain size of loose sandy soils in systems of single and double porosity. In this research we applied Time Domain Nuclear Magnetic Resonance (TD-NMR) to measure the magnetization decaying curve of samples composed of selected sizes of sand grains, poor graded sands, silty sands, silt and clay. This was performed by a CPMG pulse sequence using a low field (12 MHz) spectrometer (SLK-100). Obtained results show that transversal relaxation time and its distribution are strongly correlated with grain sizes and their distribution. These results allow improving the knowledge about pore sizes distribution when needed for modeling porous materials using numerical techniques such as pore networks.