Development of an Index to Quantify Rock Texture for Qualitative Assessment of Intact Rock Properties

Abstract

A dimensionless quantitative measure of rock texture, describing grain shape, orientation, degree of grain interlocking, and relative proportions of grains and matrix (packing density) has been developed. Data required for the model are obtained by image analysis of thin sections and concern percentage areas of grains and matrix, length, breadth, perimeter, orientation, and area of each grain in the viewing window. The results of intact mechanical property tests in eleven sedimentary and crystalline rocks are reported and correlated with the developed texture coefficient. The texture coefficient returns highly statistically significant correlations with mechanical property data and is superior to the Schmidt hammer rebound test number in this regard. Observational and correlated data are supportive of the suggestion that the texture coefficient is a qualitative measure of the resistance of the microstructure of a rock to crack propagation, whether it be integranular or intragranular. The texture coefficient can be used as a predictive tool for the assessment of mechanical rock performance. On a fundamental level it provides an insight into texture-crack propagation mechanical performance relationships.

Mechanical properties and X-ray diffraction analyses of clay/sand pellets for CO2 adsorption: the effects of sand content and humidity

“…The lower porosities of C-304 S 15% and C-304 S 25% could be related to the sand content since these particles fill the void space. According to Howarth and Rowlands (1986), high porosity is responsible for creating microfracture networks that distribute stress under compression. The porosity percentage values are summarized in Table 1.…”

Texture and index properties of rocks from Malekhu-Thopal Khola area, Central Nepal Lesser Himalaya

“…Texture coefficient (TC) was originally devised to assess the rock fabric for rock mechanics (Howarth and Rowlands, 1986 Stöcklin andBhattarai, 1977 andStöcklin, 1980) number of grains whose aspect ratio is below a pre-set discrimination level (2 in this study), N1 is the number of grains whose aspect ratio is above a pre-set discrimination level, SF0 is the arithmetic mean of discriminated shape factors 4.p.Area/(Perimeter) 2 , AR1 is the arithmetic mean ofdiscriminated aspect ratios of N1 grains calculated using Major Axis/Minor Axis, and AF1 is the angle factor, quantifying grain orientation. Grain packing AW considers intergranular space in sedimentary rocks.…”

“…Foliated rocks also have low value except in 'Kn1'. Howarth and Rowlands, 1986 developed the theory of texture coefficient (TC), which made it possible to understand the variations of mechanical properties of rocks with rock textural properties. Texture Coefficient considers grain packing weighting (AW), shape factor kg/m 3 is considered average for road construction (AASHTO, 1993).…”

Formation of synthetic structures and textures of rocks when simulating in COMSOL Multiphysics

“…Коэффициент текстуры предложен двумя австралийскими исследователями, Ховартом и Роулендсом в 1986 г. [12,13] для количественной оценки текстуры, учитывающей форму, размеры и расположение минеральных зерен, составляющих горные породы, отмечается в [14]. Связь между инженерными свойствами и текстурой горных пород была исследована на карбонатных породах [15].…”