SONGKLANAKARIN JOURNAL OF SCIENCE & TECHNOLOGY

Volume 41, No. 03, Month MAY, Year 2019, Pages 669 - 678

Shear strengths of fractures in tak granite under orthotropic stresses

Pajeeraporn Weingchanda, Supattra Khamrat, Thanitta Thongprapa, Kittitep Fuenkajorn

Abstract Download PDF

The objective of this study is to determine the shearing resistance of fractures in Tak granite as affected by orthotropic stress states where 123. Triaxial shear tests are performed to obtain the strengths and dilations of tension-induced fractures and smooth saw-cut surfaces under confining pressures up to 18 MPa. The ratios of the lateral stresses vary from 0 to 4. The shearing resistance, dilation and areas of sheared-off asperities of the rough fractures decrease when the lateral stress ratios increase. The shear strengths of smooth saw-cut surfaces tend to be independent of the stress ratios. The distortional strain energy (Wd) required to displace the fractures under various stress states increases linearly with the mean strain energy (Wm). The energy ratio (Wd/Wm) in terms of the strains and dilation can be used as a predictive tool for the movements of faults or fractures in Tak granite.

Keywords

dilation, strain energy, orthotropic stress, fault

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