An integrated study on stability assessment of the Seyrantepe underground openings (Gaziantep, Turkey)

In view of the geotechnical engineering and engineering geology, the Seyrantepe underground openings have important characteristics. Although these underground openings have thin roof thickness, large parallel span, thin pillars and low rock mass strength, they are standing up for years. Due to the rock masses being complicated and inhomogeneous material and containing discontinuities, it is commonly difficult to obtain the required mechanical parameters for the analyses. In this paper, a combined analysis, including failure-based back analysis, Hoek–Brown and Mohr–Coulomb failure criteria, was executed to determine the cohesion, frictional angle and tensile strength of the rock mass. Integrated numerical, analytical and empirical analyses were performed to assess the stability of the underground openings, which were excavated from limestone. The effects of the adjacent openings on the stability and failure zones were also investigated. The analysis shows that considerably important parameter for the roof stability is the tensile strength of the rock mass. While the lowest tensile strength is obtained from Hoek–Brown criterion, Mohr–Coulomb criterion gives the highest tensile strength. Numerical analysis shows that adjacent openings affect the stability and failure process. According to the bending theory, the limit of the roof span ranges between 11 and 22.5 m depending on roof thicknesses of 9 and 25 m, respectively. Although these underground openings are standing for a long time, results of the analyses show that some protective measures against instability are necessary. © 2021, Saudi Society for Geosciences

Çimento Esaslı Enjeksiyon Harcının Farklı Su-Çimento Oranlarında Pirinç Kabuğu Tozunun Reolojik Özelliklerine Etkisi

Pirinç kabuğu tozu (RHP) ilave edilmiş grout karışımlarının akışkanlık ve reolojik özellikleri incelenmiştir. Deneyler farklı su/ çimento oranları (0.75, 1.00, 1.25 ve 1.50) ve farklı pirinç kabuğu tozu (sırasıyla, % 4,% 8,% 12,% 16 ve % 20) kullanılarak gerçekleştirilmiştir. Bu deney atık malzemelerin depolama alanlarına bertarafı hakkında çözüm bulmak ve çevre tasarrufunda pirinç sanayisine yardımcı olmak,çevreyi atık maddeden kurtarmak, belediyeleri bu maddenin kullanılmasında teşvik etmek ve geliştiriciler için yeni bilgi sağlamak ve grout yöntemlerini geliştirmek amaçlanmaktadır. Yapılan araştırma için testlerden kesin veriler toplanmış ve tamamen laboratuarda test sonuçları alınmıştırThe fluidity and rheological properties of the grout mixtures treated with rice husk powder (RHP) were studied. The experiments were done by using different RHP content (%4, %8, %12, %16 and %20 respectively) with cement grouts proportioned with different water to cement ratio (0.75, 1.00, 1.25 and 1.50). This experiment aims to help contribute to the industry in saving the environment, to encourage the municipality to find solutions regarding the disposal to landfills of waste materials and save the environment, to provide new knowledge to the contractors and developers on how to improve the grout methods and services by using rice husk, and to sustain good product performance and meet recycling goals. Observations from the tests performed were conducted in the laboratory where precise data were gathered and completely attaine

Thermoluminescence studies of calcite conducted by bacterial CaCO3 precipitation in organic soil

In this study, the thermoluminescence (TL) properties of the calcite conducted by bacterial calcium carbonate (CaCO3) precipitation (BCCP) in organic soils were investigated. The bacterial calcium carbonate (CaCO3) precipitation (BCCP) is a popular technique and has been applied in a variety of civil and geotechnical engineering applications. For example, bacterial calcium carbonate precipitation fills the gaps on the organic ground and makes cementing it with the biological method using bacteria. The study reveals that the calcium carbonate mineral called as calcite has a clear TL glow curve with four main peaks located around 90, 140, 210 and 240 °C, a wide linear dose response region between 140Gy and 2.3 kGy is observed. In addition, a good reusability is seen in the high temperature peaks. The TL glow curve peaks are not affected by reusability. Although the dosimetric peaks at 210 and 240 °C appear to be nearly constant, the TL peak intensities at 90 °C and 140 °C completely faded after 24 and 336 h storage time, respectively. The activation energies (Ea) and frequency factors (s) for peaks at 90 °C, 140 °C, 210 °C and 240 °C were evaluated via variable heating rate (VHR). The activation energy of the peaks in the TL glow curve is lying between 0.57eV and 1.04 eV. © 2022 Elsevier Lt