A greedy approach for two-dimensional simulations of fault gouge particles.
详细信息
文摘
Changes in the porosity of deforming rock material within a geologic fault zone (fault zone) is critical to the mechanics of gouge friction and stability of seismically active faults. Samples of experimental and natural fault gouges were obtained. Outlining of gouge particle overlays were made manually on telescopic SEM images of the deformed and undeformed gouge samples. The overlays were used for PSD (Particle Size Distribution), fractal dimension, and particle shape (the number of straight sides per particle) measurements. PSD obtained from the Image Processing method was used as input data by the program designed in this study to determine the gouge porosity.;The objective was to estimate the gouge porosity, understand its effect on a deforming fault zone and identify the changes in coefficient of friction. Two-dimensional computer simulations of fault gouge texture were performed in VC++ to determine porosity in various regions of the gouge. The algorithm was without limitation on size and number of particles and designed to produce maximum packing density also program is able to generate different textures.;The results suggest that particles tend to become more equant ( circular) in shape in regions of extreme comminution along Y and R-shears in the gouge. The sharp decrease in local porosity results in packing density increases. Based on brittle-ductile transition data for porous rock material this porosity reduction could cause local embrittlement and shear fracture of the gouge. (Abstract shortened by UMI.)