Water Saturation Influences on Engineering Properties of Selected Sedimentary Rocks of Pakistan
Y. Majeed, M. Z. Bakar Abu
University of Engineering and Technology, Lahore, 54890 Pakistan
Keywords: предел прочности на сжатие, предел прочности на растяжение, плотность горной породы, объем порового пространства, пористость, водонасыщенность, корреляция, Uniaxial compressive strength, Brazilian tensile strength, rock density, rock porosity, pore space volume, water saturation, correlation
Abstract
Geomechanical properties of host rock are generally affected by the variation of moisture content present in its fabric or matrix. This study is focused to evaluate the influence of water saturation on the mechanical and physical properties of 34 sedimentary rock units selected from different geological formations in Pakistan. The laboratory testing program comprised the determination of physico-mechanical rock properties of both air-dry as well as fully water saturated rock specimens. Further thin section analyses of all rock samples were also performed to explain their petrography. According to the statistical analyzes overall reductions of around 40% and 50% were found in UCSsat and BTSsat values, respectively, measured on saturated rock samples in comparison to their corresponding dry strength values, i.e. UCSdry and BTSdry. Linear correlations were found between ultrasonic wave velocities as well as density of both dry and saturated rock samples. In addition, the dry and saturated UCS values were exponentially related with the rock porosity. Multiple regression technique was also utilized to develop a predictive linear model of UCSsat with geotechnical rock properties in the dry condition and petrographical characteristics of rock samples. Finally the validity of multiple regression model developed in this study and an existing correlation for the conversion of UCSdry into UCSsat was statistically assessed.
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