Abstract
Laboratory compressive experiments are regarded as the most accurate method to obtain the strength parameters of rock, and the rocks used for experiments are often dry. However, in geotechnical engineering, the rock masses are often under different hydraulic environments because of which rock strength decreases by varying degrees; consequently, there are considerable differences between laboratory results and engineering practices. Research on the quantitative relationships between rock strength and water content would contribute to the application of laboratory results to engineering practice and can become the basis for engineering rock mass stability analysis and forecasting. On the basis of 14 different groups of rock strength data with different water contents, statistical and numerical methods are used to obtain the least squares fit relationship between rock strength and water content, and the fitting results demonstrate that sandstone strength and water content have a negative exponential relationship. Meanwhile, through parameter analysis, we obtain the physical meaning of each parameter in the three-parameter exponential fitting curves, thus establishing the laws that govern the weakening of rock uniaxial compressive strength. The newly established model takes the rock porosity and water content into account, and the rock strength at a certain water content can be computed according to the experimentally obtained rock strength in dry and completely water-saturated conditions, as well as the rock porosity. The model has been validated by two case studies using comparative analysis between theoretical values and experimental data.
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Acknowledgments
This work was financially supported by the Open Fund (Number: PLN1421) of the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), the SWPU Science & Technology Fund (Number: 2013XJZ029), the scientific fund of the Sichuan Provincial Education Department (Number: 14ZB0060), and the CNPC Key Laboratory of Drilling Engineering.
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Shi, X., Cai, W., Meng, Y. et al. Weakening laws of rock uniaxial compressive strength with consideration of water content and rock porosity. Arab J Geosci 9, 369 (2016). https://doi.org/10.1007/s12517-016-2426-6
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DOI: https://doi.org/10.1007/s12517-016-2426-6