Browsing by Author "Acar, Altay"

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The Effects of Discontinuity Surface Roughness on the Shear Strength of Weathered Granite Joints
(Springer Heidelberg, 2014) Ozvan, Ali; Dincer, Ismail; Acar, Altay; Ozvan, Burcu
Surface roughness is one of the most important parameters governing the shear strength of rock discontinuities. Roughness types may vary based on genesis, physico-mechanical, and mineralogical properties of rocks. In this study, granite samples representing three different weathering degrees were selected to evaluate the effects of surface roughness and weathering degree on shear strength. To this aim, we determined the profile roughness coefficient (PRC), profile roughness angle (PRA), and joint roughness coefficient (JRC) for the selected fresh and weathered granite joint samples. Values of PRC were in the range of about 1.043-1.073, and PRA and JRC varied in the ranges of 16.67-21.45 and 12-18, respectively. Weathering led to the increment of joint surface roughness of the selected granitic joints due to the higher resistance of quartz crystals in the weathered matrix. However, the increment in surface roughness did not result in an increase in the shear strength. On the contrary, the shear strength of discontinuities dramatically decreased.
Quality Assessment of Geo-Materials for Coastal Structures (Yumurtalik, Turkey)
(Taylor & Francis inc, 2011) Ozvan, Ali; Dincer, Ismail; Acar, Altay
Rubble mound breakwater is one of the most important coastal engineering structures for shore and harbor protection. Standard rock quality evaluation processes were performed on massive basalt, vesicular basalt, crystallized limestone, and micritic limestone from southeast of Turkey. The rock types were evaluated within five different rock quality classification systems (CIRIA, CUR, CETMEF 2007; Lienhart 1998; Winkler 1986; Fookes et al. 1988; BS 812). The methods of CIRIA, CUR, CETMEF (2007) and Lienhart (1998) were shown to be more successful than other methods, which are insufficient to explain rock quality. Massive basalt and micritic limestone can be used as armourstone, filter layer, and core materials, but vesicular and crystallized limestone provided engineering requirements for only core materials. Vesicular basalt and crystalline limestone exhibited few poor features in terms of strength, such as iddingsite, stylolites, and micro cracks. These features can favorably affect rock strength, and oppositely affect rock quality.