Browsing by Author "Mekael, Ahmad"
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Item AN INVESTIGATION FOR THE RESIDUAL STRENGTH OF REMOULDED CLAY SPECIMENS RECOVERED FROM ORDUKÖY LANDSLIDE IN NORTHERN TURKEY(2017-01-07) Mekael, Ahmad; Akış, Ebru; Yılmaz, M. TolgaLandslides are among the frequent natural disasters in Turkey. In order to take effective remedial measures for active landslides, their mechanism should be accurately modeled for analyses. The uncertainty regarding the residual shear strength on failure plane is a significant issue to be solved for a reliable model. The residual shear strength can be measured by multi-reversal direct shear tests and ring shear tests in laboratories, and by vane tests on the sites of landslides. In the scope of this study, the residual shear strength of remoulded clay specimens recovered from a landslide in Sinop Province of Turkey is investigated by the multi-reversal direct shear test results. Atterberg limits for clay specimens are LL=64, PI=43 and clay fraction in the specimens is 59.5%. A big consolidation box has been built to reduce the total time necessary for consolidation before shearing, and to solve the issues relevant to squeezing the very soft remoulded clay in direct shear box, and to prepare uniform specimens for testing. Multi-reversal direct shear tests on consolidated specimens were run with shearing rates ranging from 0.0007 mm/min to 0.024 mm/min. The number of shearing cycles was ranging from 5 to 9. The set of normal stress included the figures 51.1, 102.2, and 204.4 kPa. The rate effect on residual shear strength was observed in the tests, and a number of preliminary observations on this effect was explained for consideration in future testing studies. In this study, the residual friction angle is supposed to be the secant friction angle (c=0) during mobilization of residual strength. The secant friction angle is estimated to be ranging from 11.7° to 13.2° . The limitations of this study are criticized. The estimated range of angle of residual strength was observed to be reasonably consistent with empirical relationships presented in literature and with the figures estimated according to the limit-equilibrium analyses of the landslide.