M Kianpour; M Sayari; A Uromeihy; M.R Nikudel
Abstract
Shear strength is one of the most important properties of mudrocks and shales in rock engineering and engineering geology. Because of the difficulty to obtain undisturbed samples of shales as required for determination of shear strength parameters, it is also the most difficult to evaluate. This research ...
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Shear strength is one of the most important properties of mudrocks and shales in rock engineering and engineering geology. Because of the difficulty to obtain undisturbed samples of shales as required for determination of shear strength parameters, it is also the most difficult to evaluate. This research investigated properties that can be used to predict the shear strength parameters of Shemshak formation shales. Thirty samples of shales from various depths were collected from boreholes in Shemshak formation in the site of Siahbishe pumped storage powerhouse. Shear strength parameters (c and ϕ), tensile strength (TS), quartz percent (Qz %), porosity (n) and density (ρ) were determined in lab for each sample. Data were analyzed statistically and with fuzzy inference system to determine the relationships between shear strength parameters with other properties. Results show that cohesion and friction angle of shales can be meaningfully predicted from a few engineering properties by fuzzy inference system. The adjusted R2 values between measured and predicted values for cohesion and friction angle are 0.95 and 0.84 respectively. Also the variation of regression coefficient (R2), performance indices (VAF) and root mean square error (RMSE) with were calculated as for the shear strength parameters, obtained from the multiple regression modeland the fuzzyinference system, revealed that the prediction performance and accuracy of the fuzzy models are high and multiple regression equations not have performance in prediction of shear strength parameters of shales.
M. Kianpour; M. Sayari; A. Oromiea
Abstract
The uniaxial compressive strength and modulus of deformability of intact rocks are highly important parameters for rock engineering and engineering geology projects. Because of the difficulty of measuring these parameters and the need for laboratory equipments for their prediction, indirect methods ...
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The uniaxial compressive strength and modulus of deformability of intact rocks are highly important parameters for rock engineering and engineering geology projects. Because of the difficulty of measuring these parameters and the need for laboratory equipments for their prediction, indirect methods are often used. In this study, some predictive models using regression analysis and fuzzy inference system have been developed for the Shales cropping out in the Shemshak formation in Siahbishe area. For this purpose, a series of easy measurable parameters such as density, porosity and point load index were applied. Both multiple regression analyses and the fuzzy inference system exhibited good performance in prediction of the uniaxial compressive strength and modulus of deformability. The variation of regression coefficient (R2), performance indices (VAF) and root mean square error (RMSE) were calculated as for the uniaxial compressive strength and the modulus of deformability obtained from the multiple regression model and the fuzzy inference system revealed that the prediction performances and accuracy of the fuzzy model are higher than those of multiple regression equations in prediction of uniaxial compressive strength and modulus of deformability.
A. Bayet goll; M. Hosseini-Barzi
Abstract
Geochemical analysis of major elements from 12 sampels from Shirgesht Formation sandstones and shales with Ordovicien age in sections of kuh-Asheghan and Kuh-Rahdar at Kalmard block in Central Iran zone, and plotting these data on silisiclastic rocks classification diagrams, show that they are quartzarenite ...
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Geochemical analysis of major elements from 12 sampels from Shirgesht Formation sandstones and shales with Ordovicien age in sections of kuh-Asheghan and Kuh-Rahdar at Kalmard block in Central Iran zone, and plotting these data on silisiclastic rocks classification diagrams, show that they are quartzarenite and shale. Moreover, the use of discrimination, biplot triangular diagrams determined the quartzose recycled provenance (craton and recycled orogen) and passive margin tectonic setting for these deposites. These data suggest the quartzose sedimentary provenace for sandstones and intermediate to felsic ignious provenance for shale. Furthermore, determination of weathering influence in source area, by using CIA index, indicated that the source area of these deposites has been exposed to intense weathering. This can be explained by humid weather in source area of passive continental margin.
