The effects of discontinuity surface roughness on the shear strength of weathered granite joints

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. © 2013 Springer-Verlag Berlin Heidelberg

A new empirical correlation between pressuremeter modules (EM) and shear wave velocity (Vs) for clay soils

The pressuremeter (PMT) and standard penetration (SPT) tests are the most common in situ tests used for determining the engineering properties of soils and rocks. PMT method can be used to determine the deformation and strength properties of soil or very blocky rock masses. PMT procedure is time-consuming and expensive, and it requires advanced testing equipment. Both SPT and PMT methods also require drilling to be performed in the area. The shear wave velocity (Vs) is a parameter obtained using active and passive seismic methods and provides insight into the strength properties of the soil and rock. Vs is easy to obtain with these methods and can be determined in all kinds of field conditions. Due to the difficulties experienced during many types of in-situ tests, numerous empirical equations for the soil or rock units have been proposed in the literature that are based on Vs. In this paper, correlations of Menard Deformation Modules (EM) with the corrected SPT blow counts (SPT-N60) and shear wave velocity (Vs) data were conducted. For this purpose, parameters of the pressuremeter were defined as a function of two variables. In order to determine the relationship between the results of these field tests and the results obtained from high-consolidated clayey soils with high and low plasticity properties, 10 boreholes with a depth of 15 m were drilled and in-situ tests were carried out at diverse depths. In addition, seismic measurements were performed at the same locations and depth-based Vs velocity data was obtained. It was concluded that EM could be predicted as a function of SPT-N60 and Vs values, and the predictions had relatively high R2 values of 0.77 and 0.75, respectively. This study thereby introduces to the literature empirical equations between EM and Vs for the first time. As soil properties are heterogeneous and anisotropic, it has been shown that it is more appropriate to use the equations produced from logarithmic and exponential relations in both single and multiple statistical analysis. © 2019 Elsevier B.V

A study of the relationship between the pressuremeter modulus and the preconsolidation pressure around a thrust fault

The study area is in a zone under the influence of the Lake Van water changes and the Van fault, which caused a destructive earthquake in 2011. Due to the level changes of Lake Van, sediments with different thicknesses as well as grain sizes were deposited in this region and the characteristics of these sediments were significantly affected by the morphology and lake water fluctuations in the past. A total of six boreholes were drilled along a 3-km line within the study area to determine the preconsolidation pressure (?pc) and the pressuremeter test values of the clayey levels of old lake deposits—which are known to have different physical and mechanical properties—with hopes to gain an insight on how they influence the mechanical tests performed in the field and in laboratory conditions. The relationship between these values was also statistically evaluated. When both datasets were evaluated together, it was determined that the stresses in the area close to the Van Thrust Fault plane caused deformations in the soil, which in turn affected the hanging-wall block of the thrust fault in particular. The inspection of EM and ?pc values for the area within the primary compression zone of the Van Fault revealed that both values of the boreholes on the footwall block were higher compared to other boreholes close to the lake (southwest). This finding indicates that the fault stresses at the footwall block of the fault plane enhance the mechanical characteristics of the soil. The data obtained were also evaluated using regression analysis. Relationships between all available data were investigated and a high coefficient of determination was derived between the Menard deformation modulus (EM) and the preconsolidation (?pc) pressure. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.2017-FBA-6347The Scientific Research Projects Office of Van Yüzüncü Yıl University (YYU-BAP, Project Number 2017-FBA-6347) financially supported this study. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations

Evaluation of availability of delihalil basalt levels (Eastern mediterranean) for rubble mound breakwater [Kıyı koruma yapıları için delihalil bazalt seviyelerinin (Doğu Akdeniz) kullanılabilirliğinin değerlendirilmesi]

Rubble mound breakwater is one of the most important structures for shore and harbor. Durable and high quality natural rocks are commonly used to protect coastal engineering structures from the waves. In this study, numerous laboratory tests were performed for the quality assessment of different basalt levels for rubble mound breakwater in the Yumurtalik (Eastern Mediterranean) region in this study. Two different basalt types were observed in study area. These levels were evaluated with different rock quality classification systems. Basalts were grouped into two classes as massive and vesicular. Idding site is a product of alteration of olivine minerals, which are commonly observed in the vesicular basalt. Vesicular basalt levels showed poor rock material strength due to alteration. The vesicular basalt levels in the study area should not be used for armourstones. © 2015, TMMOB - Jeoloji Muhendisleri Odasi. All Rights Reserved

Quality assessment of geo-materials for coastal structures (Yumurtalik, Turkey)

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. © Taylor & Francis Group, LLC

Modeling of the angle of shearing resistance of soils using soft computing systems

Precise determination of the effective angle of shearing resistance (?{symbol}') value is a major concern and an essential criterion in the design process of the geotechnical structures, such as foundations, embankments, roads, slopes, excavation and liner systems for the solid waste. The experimental determination of ?{symbol}' is often very difficult, expensive and requires extreme cautions and labor. Therefore many statistical and numerical modeling techniques have been suggested for the ?{symbol}' value. However they can only consider no more than one parameter, in a simplified manner and do not provide consistent accurate prediction of the ?{symbol}' value. This study explores the potential of Genetic Expression Programming, Artificial Neural Network (ANN) and Adaptive Neuro Fuzzy (ANFIS) computing paradigm in the prediction of ?{symbol}' value of soils. The data from consolidated-drained triaxial tests (CID) conducted in this study and the different project in Turkey and literature were used for training and testing of the models. Four basic physical properties of soils that cover the percentage of fine grained (FG), the percentage of coarse grained (CG), liquid limit (LL) and bulk density (BD) were presented to the models as input parameters. The performance of models was comprehensively evaluated some statistical criteria. The results revealed that GEP model is fairly promising approach for the prediction of angle of shearing resistance of soils. The statistical performance evaluations showed that the GEP model significantly outperforms the ANN and ANFIS models in the sense of training performances and prediction accuracies. © 2009 Elsevier Ltd. All rights reserved